Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Methods](https://developer.android.com/reference/java/nio/file/Files#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/java/nio/file/Files#inhmethods)
# Files
`
public
final
class
Files
`
`
extends https://developer.android.com/reference/java/lang/Object
`
`
`
|---|---|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||
| ↳ | java.nio.file.Files |
*** ** * ** ***
This class consists exclusively of static methods that operate on files,
directories, or other types of files.
In most cases, the methods defined here will delegate to the associated
file system provider to perform the file operations.
## Summary
| ### Public methods ||
|---|---|
| ` static long` | ` https://developer.android.com/reference/java/nio/file/Files#copy(java.nio.file.Path,%20java.io.OutputStream)(https://developer.android.com/reference/java/nio/file/Path source, https://developer.android.com/reference/java/io/OutputStream out) ` Copies all bytes from a file to an output stream. |
| ` static long` | ` https://developer.android.com/reference/java/nio/file/Files#copy(java.io.InputStream,%20java.nio.file.Path,%20java.nio.file.CopyOption[])(https://developer.android.com/reference/java/io/InputStream in, https://developer.android.com/reference/java/nio/file/Path target, https://developer.android.com/reference/java/nio/file/CopyOption options) ` Copies all bytes from an input stream to a file. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#copy(java.nio.file.Path,%20java.nio.file.Path,%20java.nio.file.CopyOption[])(https://developer.android.com/reference/java/nio/file/Path source, https://developer.android.com/reference/java/nio/file/Path target, https://developer.android.com/reference/java/nio/file/CopyOption options) ` Copy a file to a target file. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#createDirectories(java.nio.file.Path,%20java.nio.file.attribute.FileAttribute[])(https://developer.android.com/reference/java/nio/file/Path dir, https://developer.android.com/reference/java/nio/file/attribute/FileAttribute attrs) ` Creates a directory by creating all nonexistent parent directories first. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#createDirectory(java.nio.file.Path,%20java.nio.file.attribute.FileAttribute[])(https://developer.android.com/reference/java/nio/file/Path dir, https://developer.android.com/reference/java/nio/file/attribute/FileAttribute attrs) ` Creates a new directory. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#createFile(java.nio.file.Path,%20java.nio.file.attribute.FileAttribute[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/attribute/FileAttribute attrs) ` Creates a new and empty file, failing if the file already exists. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#createLink(java.nio.file.Path,%20java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path link, https://developer.android.com/reference/java/nio/file/Path existing) ` Creates a new link (directory entry) for an existing file *(optional operation)*. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#createSymbolicLink(java.nio.file.Path,%20java.nio.file.Path,%20java.nio.file.attribute.FileAttribute[])(https://developer.android.com/reference/java/nio/file/Path link, https://developer.android.com/reference/java/nio/file/Path target, https://developer.android.com/reference/java/nio/file/attribute/FileAttribute attrs) ` Creates a symbolic link to a target *(optional operation)*. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#createTempDirectory(java.lang.String,%20java.nio.file.attribute.FileAttribute[])(https://developer.android.com/reference/java/lang/String prefix, https://developer.android.com/reference/java/nio/file/attribute/FileAttribute attrs) ` Creates a new directory in the default temporary-file directory, using the given prefix to generate its name. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#createTempDirectory(java.nio.file.Path,%20java.lang.String,%20java.nio.file.attribute.FileAttribute[])(https://developer.android.com/reference/java/nio/file/Path dir, https://developer.android.com/reference/java/lang/String prefix, https://developer.android.com/reference/java/nio/file/attribute/FileAttribute attrs) ` Creates a new directory in the specified directory, using the given prefix to generate its name. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#createTempFile(java.lang.String,%20java.lang.String,%20java.nio.file.attribute.FileAttribute[])(https://developer.android.com/reference/java/lang/String prefix, https://developer.android.com/reference/java/lang/String suffix, https://developer.android.com/reference/java/nio/file/attribute/FileAttribute attrs) ` Creates an empty file in the default temporary-file directory, using the given prefix and suffix to generate its name. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#createTempFile(java.nio.file.Path,%20java.lang.String,%20java.lang.String,%20java.nio.file.attribute.FileAttribute[])(https://developer.android.com/reference/java/nio/file/Path dir, https://developer.android.com/reference/java/lang/String prefix, https://developer.android.com/reference/java/lang/String suffix, https://developer.android.com/reference/java/nio/file/attribute/FileAttribute attrs) ` Creates a new empty file in the specified directory, using the given prefix and suffix strings to generate its name. |
| ` static void` | ` https://developer.android.com/reference/java/nio/file/Files#delete(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Deletes a file. |
| ` static boolean` | ` https://developer.android.com/reference/java/nio/file/Files#deleteIfExists(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Deletes a file if it exists. |
| ` static boolean` | ` https://developer.android.com/reference/java/nio/file/Files#exists(java.nio.file.Path,%20java.nio.file.LinkOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/LinkOption options) ` Tests whether a file exists. |
| ` static https://developer.android.com/reference/java/util/stream/Stream` | ` https://developer.android.com/reference/java/nio/file/Files#find(java.nio.file.Path,%20int,%20java.util.function.BiPredicate,%20java.nio.file.FileVisitOption[])(https://developer.android.com/reference/java/nio/file/Path start, int maxDepth, https://developer.android.com/reference/java/util/function/BiPredicate matcher, https://developer.android.com/reference/java/nio/file/FileVisitOption options) ` Return a `Stream` that is lazily populated with `Path` by searching for files in a file tree rooted at a given starting file. |
| ` static https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/nio/file/Files#getAttribute(java.nio.file.Path,%20java.lang.String,%20java.nio.file.LinkOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/lang/String attribute, https://developer.android.com/reference/java/nio/file/LinkOption options) ` Reads the value of a file attribute. |
| ` static V` | ` https://developer.android.com/reference/java/nio/file/Files#getFileAttributeView(java.nio.file.Path,%20java.lang.Class,%20java.nio.file.LinkOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/lang/Class type, https://developer.android.com/reference/java/nio/file/LinkOption options) ` Returns a file attribute view of a given type. |
| ` static https://developer.android.com/reference/java/nio/file/FileStore` | ` https://developer.android.com/reference/java/nio/file/Files#getFileStore(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Returns the `https://developer.android.com/reference/java/nio/file/FileStore` representing the file store where a file is located. |
| ` static https://developer.android.com/reference/java/nio/file/attribute/FileTime` | ` https://developer.android.com/reference/java/nio/file/Files#getLastModifiedTime(java.nio.file.Path,%20java.nio.file.LinkOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/LinkOption options) ` Returns a file's last modified time. |
| ` static https://developer.android.com/reference/java/nio/file/attribute/UserPrincipal` | ` https://developer.android.com/reference/java/nio/file/Files#getOwner(java.nio.file.Path,%20java.nio.file.LinkOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/LinkOption options) ` Returns the owner of a file. |
| ` static https://developer.android.com/reference/java/util/Set` | ` https://developer.android.com/reference/java/nio/file/Files#getPosixFilePermissions(java.nio.file.Path,%20java.nio.file.LinkOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/LinkOption options) ` Returns a file's POSIX file permissions. |
| ` static boolean` | ` https://developer.android.com/reference/java/nio/file/Files#isDirectory(java.nio.file.Path,%20java.nio.file.LinkOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/LinkOption options) ` Tests whether a file is a directory. |
| ` static boolean` | ` https://developer.android.com/reference/java/nio/file/Files#isExecutable(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Tests whether a file is executable. |
| ` static boolean` | ` https://developer.android.com/reference/java/nio/file/Files#isHidden(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Tells whether or not a file is considered *hidden*. |
| ` static boolean` | ` https://developer.android.com/reference/java/nio/file/Files#isReadable(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Tests whether a file is readable. |
| ` static boolean` | ` https://developer.android.com/reference/java/nio/file/Files#isRegularFile(java.nio.file.Path,%20java.nio.file.LinkOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/LinkOption options) ` Tests whether a file is a regular file with opaque content. |
| ` static boolean` | ` https://developer.android.com/reference/java/nio/file/Files#isSameFile(java.nio.file.Path,%20java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/Path path2) ` Tests if two paths locate the same file. |
| ` static boolean` | ` https://developer.android.com/reference/java/nio/file/Files#isSymbolicLink(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Tests whether a file is a symbolic link. |
| ` static boolean` | ` https://developer.android.com/reference/java/nio/file/Files#isWritable(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Tests whether a file is writable. |
| ` static https://developer.android.com/reference/java/util/stream/Stream` | ` https://developer.android.com/reference/java/nio/file/Files#lines(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Read all lines from a file as a `Stream`. |
| ` static https://developer.android.com/reference/java/util/stream/Stream` | ` https://developer.android.com/reference/java/nio/file/Files#lines(java.nio.file.Path,%20java.nio.charset.Charset)(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/charset/Charset cs) ` Read all lines from a file as a `Stream`. |
| ` static https://developer.android.com/reference/java/util/stream/Stream` | ` https://developer.android.com/reference/java/nio/file/Files#list(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path dir) ` Return a lazily populated `Stream`, the elements of which are the entries in the directory. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#move(java.nio.file.Path,%20java.nio.file.Path,%20java.nio.file.CopyOption[])(https://developer.android.com/reference/java/nio/file/Path source, https://developer.android.com/reference/java/nio/file/Path target, https://developer.android.com/reference/java/nio/file/CopyOption options) ` Move or rename a file to a target file. |
| ` static https://developer.android.com/reference/java/io/BufferedReader` | ` https://developer.android.com/reference/java/nio/file/Files#newBufferedReader(java.nio.file.Path,%20java.nio.charset.Charset)(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/charset/Charset cs) ` Opens a file for reading, returning a `BufferedReader` that may be used to read text from the file in an efficient manner. |
| ` static https://developer.android.com/reference/java/io/BufferedReader` | ` https://developer.android.com/reference/java/nio/file/Files#newBufferedReader(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Opens a file for reading, returning a `BufferedReader` to read text from the file in an efficient manner. |
| ` static https://developer.android.com/reference/java/io/BufferedWriter` | ` https://developer.android.com/reference/java/nio/file/Files#newBufferedWriter(java.nio.file.Path,%20java.nio.charset.Charset,%20java.nio.file.OpenOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/charset/Charset cs, https://developer.android.com/reference/java/nio/file/OpenOption options) ` Opens or creates a file for writing, returning a `BufferedWriter` that may be used to write text to the file in an efficient manner. |
| ` static https://developer.android.com/reference/java/io/BufferedWriter` | ` https://developer.android.com/reference/java/nio/file/Files#newBufferedWriter(java.nio.file.Path,%20java.nio.file.OpenOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/OpenOption options) ` Opens or creates a file for writing, returning a `BufferedWriter` to write text to the file in an efficient manner. |
| ` static https://developer.android.com/reference/java/nio/channels/SeekableByteChannel` | ` https://developer.android.com/reference/java/nio/file/Files#newByteChannel(java.nio.file.Path,%20java.util.Set,%20java.nio.file.attribute.FileAttribute[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/util/Set options, https://developer.android.com/reference/java/nio/file/attribute/FileAttribute attrs) ` Opens or creates a file, returning a seekable byte channel to access the file. |
| ` static https://developer.android.com/reference/java/nio/channels/SeekableByteChannel` | ` https://developer.android.com/reference/java/nio/file/Files#newByteChannel(java.nio.file.Path,%20java.nio.file.OpenOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/OpenOption options) ` Opens or creates a file, returning a seekable byte channel to access the file. |
| ` static https://developer.android.com/reference/java/nio/file/DirectoryStream` | ` https://developer.android.com/reference/java/nio/file/Files#newDirectoryStream(java.nio.file.Path,%20java.lang.String)(https://developer.android.com/reference/java/nio/file/Path dir, https://developer.android.com/reference/java/lang/String glob) ` Opens a directory, returning a `https://developer.android.com/reference/java/nio/file/DirectoryStream` to iterate over the entries in the directory. |
| ` static https://developer.android.com/reference/java/nio/file/DirectoryStream` | ` https://developer.android.com/reference/java/nio/file/Files#newDirectoryStream(java.nio.file.Path,%20java.nio.file.DirectoryStream.Filter)(https://developer.android.com/reference/java/nio/file/Path dir, https://developer.android.com/reference/java/nio/file/DirectoryStream.Filter filter) ` Opens a directory, returning a `https://developer.android.com/reference/java/nio/file/DirectoryStream` to iterate over the entries in the directory. |
| ` static https://developer.android.com/reference/java/nio/file/DirectoryStream` | ` https://developer.android.com/reference/java/nio/file/Files#newDirectoryStream(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path dir) ` Opens a directory, returning a `https://developer.android.com/reference/java/nio/file/DirectoryStream` to iterate over all entries in the directory. |
| ` static https://developer.android.com/reference/java/io/InputStream` | ` https://developer.android.com/reference/java/nio/file/Files#newInputStream(java.nio.file.Path,%20java.nio.file.OpenOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/OpenOption options) ` Opens a file, returning an input stream to read from the file. |
| ` static https://developer.android.com/reference/java/io/OutputStream` | ` https://developer.android.com/reference/java/nio/file/Files#newOutputStream(java.nio.file.Path,%20java.nio.file.OpenOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/OpenOption options) ` Opens or creates a file, returning an output stream that may be used to write bytes to the file. |
| ` static boolean` | ` https://developer.android.com/reference/java/nio/file/Files#notExists(java.nio.file.Path,%20java.nio.file.LinkOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/LinkOption options) ` Tests whether the file located by this path does not exist. |
| ` static https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/nio/file/Files#probeContentType(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Probes the content type of a file. |
| ` static byte[]` | ` https://developer.android.com/reference/java/nio/file/Files#readAllBytes(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Reads all the bytes from a file. |
| ` static https://developer.android.com/reference/java/util/List` | ` https://developer.android.com/reference/java/nio/file/Files#readAllLines(java.nio.file.Path,%20java.nio.charset.Charset)(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/charset/Charset cs) ` Read all lines from a file. |
| ` static https://developer.android.com/reference/java/util/List` | ` https://developer.android.com/reference/java/nio/file/Files#readAllLines(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Read all lines from a file. |
| ` static A` | ` https://developer.android.com/reference/java/nio/file/Files#readAttributes(java.nio.file.Path,%20java.lang.Class,%20java.nio.file.LinkOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/lang/Class type, https://developer.android.com/reference/java/nio/file/LinkOption options) ` Reads a file's attributes as a bulk operation. |
| ` static https://developer.android.com/reference/java/util/Map` | ` https://developer.android.com/reference/java/nio/file/Files#readAttributes(java.nio.file.Path,%20java.lang.String,%20java.nio.file.LinkOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/lang/String attributes, https://developer.android.com/reference/java/nio/file/LinkOption options) ` Reads a set of file attributes as a bulk operation. |
| ` static https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/nio/file/Files#readString(java.nio.file.Path,%20java.nio.charset.Charset)(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/charset/Charset cs) ` Reads all characters from a file into a string, decoding from bytes to characters using the specified [charset](https://developer.android.com/reference/java/nio/charset/Charset). |
| ` static https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/nio/file/Files#readString(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Reads all content from a file into a string, decoding from bytes to characters using the `https://developer.android.com/reference/java/nio/charset/StandardCharsets#UTF_8` `https://developer.android.com/reference/java/nio/charset/Charset`. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#readSymbolicLink(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path link) ` Reads the target of a symbolic link *(optional operation)*. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#setAttribute(java.nio.file.Path,%20java.lang.String,%20java.lang.Object,%20java.nio.file.LinkOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/lang/String attribute, https://developer.android.com/reference/java/lang/Object value, https://developer.android.com/reference/java/nio/file/LinkOption options) ` Sets the value of a file attribute. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#setLastModifiedTime(java.nio.file.Path,%20java.nio.file.attribute.FileTime)(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/attribute/FileTime time) ` Updates a file's last modified time attribute. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#setOwner(java.nio.file.Path,%20java.nio.file.attribute.UserPrincipal)(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/nio/file/attribute/UserPrincipal owner) ` Updates the file owner. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#setPosixFilePermissions(java.nio.file.Path,%20java.util.Set)(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/util/Set perms) ` Sets a file's POSIX permissions. |
| ` static long` | ` https://developer.android.com/reference/java/nio/file/Files#size(java.nio.file.Path)(https://developer.android.com/reference/java/nio/file/Path path) ` Returns the size of a file (in bytes). |
| ` static https://developer.android.com/reference/java/util/stream/Stream` | ` https://developer.android.com/reference/java/nio/file/Files#walk(java.nio.file.Path,%20int,%20java.nio.file.FileVisitOption[])(https://developer.android.com/reference/java/nio/file/Path start, int maxDepth, https://developer.android.com/reference/java/nio/file/FileVisitOption options) ` Return a `Stream` that is lazily populated with `Path` by walking the file tree rooted at a given starting file. |
| ` static https://developer.android.com/reference/java/util/stream/Stream` | ` https://developer.android.com/reference/java/nio/file/Files#walk(java.nio.file.Path,%20java.nio.file.FileVisitOption[])(https://developer.android.com/reference/java/nio/file/Path start, https://developer.android.com/reference/java/nio/file/FileVisitOption options) ` Return a `Stream` that is lazily populated with `Path` by walking the file tree rooted at a given starting file. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#walkFileTree(java.nio.file.Path,%20java.nio.file.FileVisitor)(https://developer.android.com/reference/java/nio/file/Path start, https://developer.android.com/reference/java/nio/file/FileVisitor visitor) ` Walks a file tree. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#walkFileTree(java.nio.file.Path,%20java.util.Set,%20int,%20java.nio.file.FileVisitor)(https://developer.android.com/reference/java/nio/file/Path start, https://developer.android.com/reference/java/util/Set options, int maxDepth, https://developer.android.com/reference/java/nio/file/FileVisitor visitor) ` Walks a file tree. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#write(java.nio.file.Path,%20java.lang.Iterable,%20java.nio.charset.Charset,%20java.nio.file.OpenOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/lang/Iterable lines, https://developer.android.com/reference/java/nio/charset/Charset cs, https://developer.android.com/reference/java/nio/file/OpenOption options) ` Write lines of text to a file. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#write(java.nio.file.Path,%20byte[],%20java.nio.file.OpenOption[])(https://developer.android.com/reference/java/nio/file/Path path, byte[] bytes, https://developer.android.com/reference/java/nio/file/OpenOption options) ` Writes bytes to a file. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#write(java.nio.file.Path,%20java.lang.Iterable,%20java.nio.file.OpenOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/lang/Iterable lines, https://developer.android.com/reference/java/nio/file/OpenOption options) ` Write lines of text to a file. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#writeString(java.nio.file.Path,%20java.lang.CharSequence,%20java.nio.file.OpenOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/lang/CharSequence csq, https://developer.android.com/reference/java/nio/file/OpenOption options) ` Write a [CharSequence](https://developer.android.com/reference/java/lang/CharSequence) to a file. |
| ` static https://developer.android.com/reference/java/nio/file/Path` | ` https://developer.android.com/reference/java/nio/file/Files#writeString(java.nio.file.Path,%20java.lang.CharSequence,%20java.nio.charset.Charset,%20java.nio.file.OpenOption[])(https://developer.android.com/reference/java/nio/file/Path path, https://developer.android.com/reference/java/lang/CharSequence csq, https://developer.android.com/reference/java/nio/charset/Charset cs, https://developer.android.com/reference/java/nio/file/OpenOption options) ` Write a [CharSequence](https://developer.android.com/reference/java/lang/CharSequence) to a file. |
| ### Inherited methods |
|---|---|
| From class ` https://developer.android.com/reference/java/lang/Object ` |---|---| | ` https://developer.android.com/reference/java/lang/Object` | ` https://developer.android.com/reference/java/lang/Object#clone()() ` Creates and returns a copy of this object. | | ` boolean` | ` https://developer.android.com/reference/java/lang/Object#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object obj) ` Indicates whether some other object is "equal to" this one. | | ` void` | ` https://developer.android.com/reference/java/lang/Object#finalize()() ` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. | | ` final https://developer.android.com/reference/java/lang/Class` | ` https://developer.android.com/reference/java/lang/Object#getClass()() ` Returns the runtime class of this `Object`. | | ` int` | ` https://developer.android.com/reference/java/lang/Object#hashCode()() ` Returns a hash code value for the object. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#notify()() ` Wakes up a single thread that is waiting on this object's monitor. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#notifyAll()() ` Wakes up all threads that are waiting on this object's monitor. | | ` https://developer.android.com/reference/java/lang/String` | ` https://developer.android.com/reference/java/lang/Object#toString()() ` Returns a string representation of the object. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait(long,%20int)(long timeoutMillis, int nanos) ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait(long)(long timeoutMillis) ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*, or until a certain amount of real time has elapsed. | | ` final void` | ` https://developer.android.com/reference/java/lang/Object#wait()() ` Causes the current thread to wait until it is awakened, typically by being *notified* or *interrupted*. | ||
## Public methods
### copy
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static long copy (Path source,
OutputStream out)
```
Copies all bytes from a file to an output stream.
If an I/O error occurs reading from the file or writing to the output
stream, then it may do so after some bytes have been read or written.
Consequently the output stream may be in an inconsistent state. It is
strongly recommended that the output stream be promptly closed if an I/O
error occurs.
This method may block indefinitely writing to the output stream (or
reading from the file). The behavior for the case that the output stream
is *asynchronously closed* or the thread interrupted during the copy
is highly output stream and file system provider specific and therefore
not specified.
Note that if the given output stream is `https://developer.android.com/reference/java/io/Flushable`
then its `https://developer.android.com/reference/java/io/Flushable#flush()` method may need to invoked
after this method completes so as to flush any buffered output.
| Parameters ||
|---|---|
| `source` | `Path`: the path to the file
|
| `out` | `OutputStream`: the output stream to write to
|
| Returns ||
|---|---|
| `long` | the number of bytes read or written
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs when reading or writing |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file. |
### copy
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static long copy (InputStream in,
Path target,
CopyOption... options)
```
Copies all bytes from an input stream to a file. On return, the input
stream will be at end of stream.
By default, the copy fails if the target file already exists or is a
symbolic link. If the `https://developer.android.com/reference/java/nio/file/StandardCopyOption#REPLACE_EXISTING` option is specified, and the target file already exists,
then it is replaced if it is not a non-empty directory. If the target
file exists and is a symbolic link, then the symbolic link is replaced.
In this release, the `REPLACE_EXISTING` option is the only option
required to be supported by this method. Additional options may be
supported in future releases.
If an I/O error occurs reading from the input stream or writing to
the file, then it may do so after the target file has been created and
after some bytes have been read or written. Consequently the input
stream may not be at end of stream and may be in an inconsistent state.
It is strongly recommended that the input stream be promptly closed if an
I/O error occurs.
This method may block indefinitely reading from the input stream (or
writing to the file). The behavior for the case that the input stream is
*asynchronously closed* or the thread interrupted during the copy is
highly input stream and file system provider specific and therefore not
specified.
**Usage example**: Suppose we want to capture a web page and save
it to a file:
```
Path path = ...
URI u = URI.create("http://java.sun.com/");
try (InputStream in = u.toURL().openStream()) {
Files.copy(in, path);
}
```
| Parameters ||
|---|---|
| `in` | `InputStream`: the input stream to read from
|
| `target` | `Path`: the path to the file
|
| `options` | `CopyOption`: options specifying how the copy should be done
|
| Returns ||
|---|---|
| `long` | the number of bytes read or written
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs when reading or writing |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the file. Where the `REPLACE_EXISTING` option is specified, the security manager's `https://developer.android.com/reference/java/lang/SecurityManager#checkDelete(java.lang.String)` method is invoked to check that an existing file can be deleted. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if `options` contains a copy option that is not supported |
| `https://developer.android.com/reference/java/nio/file/DirectoryNotEmptyException` | the `REPLACE_EXISTING` option is specified but the file cannot be replaced because it is a non-empty directory *(optional specific exception)* \* |
| `https://developer.android.com/reference/java/nio/file/FileAlreadyExistsException` | if the target file exists but cannot be replaced because the `REPLACE_EXISTING` option is not specified *(optional specific exception)* |
### copy
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path copy (Path source,
Path target,
CopyOption... options)
```
Copy a file to a target file.
This method copies a file to the target file with the `options` parameter specifying how the copy is performed. By default, the
copy fails if the target file already exists or is a symbolic link,
except if the source and target are the `https://developer.android.com/reference/java/nio/file/Files#isSameFile(java.nio.file.Path,%20java.nio.file.Path)` file, in
which case the method completes without copying the file. File attributes
are not required to be copied to the target file. If symbolic links are
supported, and the file is a symbolic link, then the final target of the
link is copied. If the file is a directory then it creates an empty
directory in the target location (entries in the directory are not
copied). This method can be used with the `https://developer.android.com/reference/java/nio/file/Files#walkFileTree(java.nio.file.Path,%20java.nio.file.FileVisitor)` method to copy a directory and all entries in the directory,
or an entire *file-tree* where required.
The `options` parameter may include any of the following:
| Option | Description |
| `https://developer.android.com/reference/java/nio/file/StandardCopyOption#REPLACE_EXISTING` | If the target file exists, then the target file is replaced if it is not a non-empty directory. If the target file exists and is a symbolic link, then the symbolic link itself, not the target of the link, is replaced. |
| `https://developer.android.com/reference/java/nio/file/StandardCopyOption#COPY_ATTRIBUTES` | Attempts to copy the file attributes associated with this file to the target file. The exact file attributes that are copied is platform and file system dependent and therefore unspecified. Minimally, the `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes#lastModifiedTime()` is copied to the target file if supported by both the source and target file stores. Copying of file timestamps may result in precision loss. |
| `https://developer.android.com/reference/java/nio/file/LinkOption#NOFOLLOW_LINKS` | Symbolic links are not followed. If the file is a symbolic link, then the symbolic link itself, not the target of the link, is copied. It is implementation specific if file attributes can be copied to the new link. In other words, the `COPY_ATTRIBUTES` option may be ignored when copying a symbolic link. |
|---|---|
[Options]
An implementation of this interface may support additional
implementation specific options.
Copying a file is not an atomic operation. If an `https://developer.android.com/reference/java/io/IOException`
is thrown, then it is possible that the target file is incomplete or some
of its file attributes have not been copied from the source file. When
the `REPLACE_EXISTING` option is specified and the target file
exists, then the target file is replaced. The check for the existence of
the file and the creation of the new file may not be atomic with respect
to other file system activities.
**Usage Example:**
Suppose we want to copy a file into a directory, giving it the same file
name as the source file:
```
Path source = ...
Path newdir = ...
Files.copy(source, newdir.resolve(source.getFileName());
```
| Parameters ||
|---|---|
| `source` | `Path`: the path to the file to copy
|
| `target` | `Path`: the path to the target file (may be associated with a different provider to the source path)
|
| `options` | `CopyOption`: options specifying how the copy should be done
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the path to the target file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the source file, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` is invoked to check write access to the target file. If a symbolic link is copied the security manager is invoked to check `https://developer.android.com/reference/java/nio/file/LinkPermission``("symbolic")`. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the array contains a copy option that is not supported |
| `https://developer.android.com/reference/java/nio/file/DirectoryNotEmptyException` | the `REPLACE_EXISTING` option is specified but the file cannot be replaced because it is a non-empty directory *(optional specific exception)* |
| `https://developer.android.com/reference/java/nio/file/FileAlreadyExistsException` | if the target file exists but cannot be replaced because the `REPLACE_EXISTING` option is not specified *(optional specific exception)* |
### createDirectories
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path createDirectories (Path dir,
FileAttribute... attrs)
```
Creates a directory by creating all nonexistent parent directories first.
Unlike the `https://developer.android.com/reference/java/nio/file/Files#createDirectory(java.nio.file.Path,%20java.nio.file.attribute.FileAttribute[])` method, an exception
is not thrown if the directory could not be created because it already
exists.
The `attrs` parameter is optional `https://developer.android.com/reference/java/nio/file/attribute/FileAttribute` to set atomically when creating the nonexistent
directories. Each file attribute is identified by its `https://developer.android.com/reference/java/nio/file/attribute/FileAttribute#name()`. If more than one attribute of the same name is
included in the array then all but the last occurrence is ignored.
If this method fails, then it may do so after creating some, but not
all, of the parent directories.
| Parameters ||
|---|---|
| `dir` | `Path`: the directory to create
|
| `attrs` | `FileAttribute`: an optional list of file attributes to set atomically when creating the directory
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the directory
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | in the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked prior to attempting to create a directory and its `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` is invoked for each parent directory that is checked. If `dir` is not an absolute path then its `https://developer.android.com/reference/java/nio/file/Path#toAbsolutePath()` may need to be invoked to get its absolute path. This may invoke the security manager's `https://developer.android.com/reference/java/lang/SecurityManager#checkPropertyAccess(java.lang.String)` method to check access to the system property `user.dir` |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the array contains an attribute that cannot be set atomically when creating the directory |
| `https://developer.android.com/reference/java/nio/file/FileAlreadyExistsException` | if `dir` exists but is not a directory *(optional specific exception)* |
### createDirectory
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path createDirectory (Path dir,
FileAttribute... attrs)
```
Creates a new directory. The check for the existence of the file and the
creation of the directory if it does not exist are a single operation
that is atomic with respect to all other filesystem activities that might
affect the directory. The `https://developer.android.com/reference/java/nio/file/Files#createDirectories(java.nio.file.Path,%20java.nio.file.attribute.FileAttribute[])`
method should be used where it is required to create all nonexistent
parent directories first.
The `attrs` parameter is optional `https://developer.android.com/reference/java/nio/file/attribute/FileAttribute` to set atomically when creating the directory. Each
attribute is identified by its `https://developer.android.com/reference/java/nio/file/attribute/FileAttribute#name()`. If more
than one attribute of the same name is included in the array then all but
the last occurrence is ignored.
| Parameters ||
|---|---|
| `dir` | `Path`: the directory to create
|
| `attrs` | `FileAttribute`: an optional list of file attributes to set atomically when creating the directory
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the directory
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs or the parent directory does not exist |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the new directory. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the array contains an attribute that cannot be set atomically when creating the directory |
| `https://developer.android.com/reference/java/nio/file/FileAlreadyExistsException` | if a directory could not otherwise be created because a file of that name already exists *(optional specific exception)* |
### createFile
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path createFile (Path path,
FileAttribute... attrs)
```
Creates a new and empty file, failing if the file already exists. The
check for the existence of the file and the creation of the new file if
it does not exist are a single operation that is atomic with respect to
all other filesystem activities that might affect the directory.
The `attrs` parameter is optional `https://developer.android.com/reference/java/nio/file/attribute/FileAttribute` to set atomically when creating the file. Each attribute
is identified by its `https://developer.android.com/reference/java/nio/file/attribute/FileAttribute#name()`. If more than one
attribute of the same name is included in the array then all but the last
occurrence is ignored.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to create
|
| `attrs` | `FileAttribute`: an optional list of file attributes to set atomically when creating the file
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs or the parent directory does not exist |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the new file. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the array contains an attribute that cannot be set atomically when creating the file |
| `https://developer.android.com/reference/java/nio/file/FileAlreadyExistsException` | if a file of that name already exists *(optional specific exception)* |
### createLink
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path createLink (Path link,
Path existing)
```
Creates a new link (directory entry) for an existing file *(optional operation)*.
The `link` parameter locates the directory entry to create.
The `existing` parameter is the path to an existing file. This
method creates a new directory entry for the file so that it can be
accessed using `link` as the path. On some file systems this is
known as creating a "hard link". Whether the file attributes are
maintained for the file or for each directory entry is file system
specific and therefore not specified. Typically, a file system requires
that all links (directory entries) for a file be on the same file system.
Furthermore, on some platforms, the Java virtual machine may require to
be started with implementation specific privileges to create hard links
or to create links to directories.
| Parameters ||
|---|---|
| `link` | `Path`: the link (directory entry) to create
|
| `existing` | `Path`: a path to an existing file
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the path to the link (directory entry)
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, it denies `https://developer.android.com/reference/java/nio/file/LinkPermission``("hard")` or its `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method denies write access to either the link or the existing file. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the implementation does not support adding an existing file to a directory |
| `https://developer.android.com/reference/java/nio/file/FileAlreadyExistsException` | if the entry could not otherwise be created because a file of that name already exists *(optional specific exception)* |
### createSymbolicLink
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path createSymbolicLink (Path link,
Path target,
FileAttribute... attrs)
```
Creates a symbolic link to a target *(optional operation)*.
The `target` parameter is the target of the link. It may be an
`https://developer.android.com/reference/java/nio/file/Path#isAbsolute()` or relative path and may not exist. When
the target is a relative path then file system operations on the resulting
link are relative to the path of the link.
The `attrs` parameter is optional `https://developer.android.com/reference/java/nio/file/attribute/FileAttribute` to set atomically when creating the link. Each attribute is
identified by its `https://developer.android.com/reference/java/nio/file/attribute/FileAttribute#name()`. If more than one attribute
of the same name is included in the array then all but the last occurrence
is ignored.
Where symbolic links are supported, but the underlying `https://developer.android.com/reference/java/nio/file/FileStore`
does not support symbolic links, then this may fail with an `https://developer.android.com/reference/java/io/IOException`. Additionally, some operating systems may require that the
Java virtual machine be started with implementation specific privileges to
create symbolic links, in which case this method may throw `IOException`.
| Parameters ||
|---|---|
| `link` | `Path`: the path of the symbolic link to create
|
| `target` | `Path`: the target of the symbolic link
|
| `attrs` | `FileAttribute`: the array of attributes to set atomically when creating the symbolic link
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the path to the symbolic link
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, it denies `https://developer.android.com/reference/java/nio/file/LinkPermission``("symbolic")` or its `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method denies write access to the path of the symbolic link. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the implementation does not support symbolic links or the array contains an attribute that cannot be set atomically when creating the symbolic link |
| `https://developer.android.com/reference/java/nio/file/FileAlreadyExistsException` | if a file with the name already exists *(optional specific exception)* |
### createTempDirectory
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path createTempDirectory (String prefix,
FileAttribute... attrs)
```
Creates a new directory in the default temporary-file directory, using
the given prefix to generate its name. The resulting `Path` is
associated with the default `FileSystem`.
This method works in exactly the manner specified by `https://developer.android.com/reference/java/nio/file/Files#createTempDirectory(java.nio.file.Path,%20java.lang.String,%20java.nio.file.attribute.FileAttribute[])` method for the case
that the `dir` parameter is the temporary-file directory.
| Parameters ||
|---|---|
| `prefix` | `String`: the prefix string to be used in generating the directory's name; may be `null`
|
| `attrs` | `FileAttribute`: an optional list of file attributes to set atomically when creating the directory
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the path to the newly created directory that did not exist before this method was invoked
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs or the temporary-file directory does not exist |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the prefix cannot be used to generate a candidate directory name |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access when creating the directory. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the array contains an attribute that cannot be set atomically when creating the directory |
### createTempDirectory
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path createTempDirectory (Path dir,
String prefix,
FileAttribute... attrs)
```
Creates a new directory in the specified directory, using the given
prefix to generate its name. The resulting `Path` is associated
with the same `FileSystem` as the given directory.
The details as to how the name of the directory is constructed is
implementation dependent and therefore not specified. Where possible
the `prefix` is used to construct candidate names.
As with the `createTempFile` methods, this method is only
part of a temporary-file facility. A `https://developer.android.com/reference/java/lang/Runtime#addShutdownHook(java.lang.Thread)`, or the `https://developer.android.com/reference/java/io/File#deleteOnExit()` mechanism may be
used to delete the directory automatically.
The `attrs` parameter is optional `https://developer.android.com/reference/java/nio/file/attribute/FileAttribute` to set atomically when creating the directory. Each
attribute is identified by its `https://developer.android.com/reference/java/nio/file/attribute/FileAttribute#name()`. If more
than one attribute of the same name is included in the array then all but
the last occurrence is ignored.
| Parameters ||
|---|---|
| `dir` | `Path`: the path to directory in which to create the directory
|
| `prefix` | `String`: the prefix string to be used in generating the directory's name; may be `null`
|
| `attrs` | `FileAttribute`: an optional list of file attributes to set atomically when creating the directory
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the path to the newly created directory that did not exist before this method was invoked
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs or `dir` does not exist |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the prefix cannot be used to generate a candidate directory name |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access when creating the directory. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the array contains an attribute that cannot be set atomically when creating the directory |
### createTempFile
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path createTempFile (String prefix,
String suffix,
FileAttribute... attrs)
```
Creates an empty file in the default temporary-file directory, using
the given prefix and suffix to generate its name. The resulting `Path` is associated with the default `FileSystem`.
This method works in exactly the manner specified by the
`https://developer.android.com/reference/java/nio/file/Files#createTempFile(java.nio.file.Path,%20java.lang.String,%20java.lang.String,%20java.nio.file.attribute.FileAttribute[])` method for
the case that the `dir` parameter is the temporary-file directory.
| Parameters ||
|---|---|
| `prefix` | `String`: the prefix string to be used in generating the file's name; may be `null`
|
| `suffix` | `String`: the suffix string to be used in generating the file's name; may be `null`, in which case "`.tmp`" is used
|
| `attrs` | `FileAttribute`: an optional list of file attributes to set atomically when creating the file
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the path to the newly created file that did not exist before this method was invoked
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs or the temporary-file directory does not exist |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the prefix or suffix parameters cannot be used to generate a candidate file name |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the file. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the array contains an attribute that cannot be set atomically when creating the directory |
### createTempFile
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path createTempFile (Path dir,
String prefix,
String suffix,
FileAttribute... attrs)
```
Creates a new empty file in the specified directory, using the given
prefix and suffix strings to generate its name. The resulting
`Path` is associated with the same `FileSystem` as the given
directory.
The details as to how the name of the file is constructed is
implementation dependent and therefore not specified. Where possible
the `prefix` and `suffix` are used to construct candidate
names in the same manner as the `https://developer.android.com/reference/java/io/File#createTempFile(java.lang.String,%20java.lang.String,%20java.io.File)` method.
As with the `File.createTempFile` methods, this method is only
part of a temporary-file facility. Where used as a *work files* ,
the resulting file may be opened using the `https://developer.android.com/reference/java/nio/file/StandardOpenOption#DELETE_ON_CLOSE` option so that the
file is deleted when the appropriate `close` method is invoked.
Alternatively, a `https://developer.android.com/reference/java/lang/Runtime#addShutdownHook(java.lang.Thread)`, or the
`https://developer.android.com/reference/java/io/File#deleteOnExit()` mechanism may be used to delete the
file automatically.
The `attrs` parameter is optional `https://developer.android.com/reference/java/nio/file/attribute/FileAttribute` to set atomically when creating the file. Each attribute
is identified by its `https://developer.android.com/reference/java/nio/file/attribute/FileAttribute#name()`. If more than one
attribute of the same name is included in the array then all but the last
occurrence is ignored. When no file attributes are specified, then the
resulting file may have more restrictive access permissions to files
created by the `https://developer.android.com/reference/java/io/File#createTempFile(java.lang.String,%20java.lang.String,%20java.io.File)`
method.
| Parameters ||
|---|---|
| `dir` | `Path`: the path to directory in which to create the file
|
| `prefix` | `String`: the prefix string to be used in generating the file's name; may be `null`
|
| `suffix` | `String`: the suffix string to be used in generating the file's name; may be `null`, in which case "`.tmp`" is used
|
| `attrs` | `FileAttribute`: an optional list of file attributes to set atomically when creating the file
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the path to the newly created file that did not exist before this method was invoked
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs or `dir` does not exist |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the prefix or suffix parameters cannot be used to generate a candidate file name |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the file. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the array contains an attribute that cannot be set atomically when creating the directory |
### delete
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static void delete (Path path)
```
Deletes a file.
An implementation may require to examine the file to determine if the
file is a directory. Consequently this method may not be atomic with respect
to other file system operations. If the file is a symbolic link then the
symbolic link itself, not the final target of the link, is deleted.
If the file is a directory then the directory must be empty. In some
implementations a directory has entries for special files or links that
are created when the directory is created. In such implementations a
directory is considered empty when only the special entries exist.
This method can be used with the `https://developer.android.com/reference/java/nio/file/Files#walkFileTree(java.nio.file.Path,%20java.nio.file.FileVisitor)`
method to delete a directory and all entries in the directory, or an
entire *file-tree* where required.
On some operating systems it may not be possible to remove a file when
it is open and in use by this Java virtual machine or other programs.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to delete
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkDelete(java.lang.String)` method is invoked to check delete access to the file |
| `https://developer.android.com/reference/java/nio/file/DirectoryNotEmptyException` | if the file is a directory and could not otherwise be deleted because the directory is not empty *(optional specific exception)* |
| `https://developer.android.com/reference/java/nio/file/NoSuchFileException` | if the file does not exist *(optional specific exception)* |
### deleteIfExists
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static boolean deleteIfExists (Path path)
```
Deletes a file if it exists.
As with the `https://developer.android.com/reference/java/nio/file/Files#delete(java.nio.file.Path)` method, an
implementation may need to examine the file to determine if the file is a
directory. Consequently this method may not be atomic with respect to
other file system operations. If the file is a symbolic link, then the
symbolic link itself, not the final target of the link, is deleted.
If the file is a directory then the directory must be empty. In some
implementations a directory has entries for special files or links that
are created when the directory is created. In such implementations a
directory is considered empty when only the special entries exist.
On some operating systems it may not be possible to remove a file when
it is open and in use by this Java virtual machine or other programs.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to delete
|
| Returns ||
|---|---|
| `boolean` | `true` if the file was deleted by this method; `false` if the file could not be deleted because it did not exist
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkDelete(java.lang.String)` method is invoked to check delete access to the file. |
| `https://developer.android.com/reference/java/nio/file/DirectoryNotEmptyException` | if the file is a directory and could not otherwise be deleted because the directory is not empty *(optional specific exception)* |
### exists
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static boolean exists (Path path,
LinkOption... options)
```
Tests whether a file exists.
The `options` parameter may be used to indicate how symbolic links
are handled for the case that the file is a symbolic link. By default,
symbolic links are followed. If the option `https://developer.android.com/reference/java/nio/file/LinkOption#NOFOLLOW_LINKS` is present then symbolic links are not followed.
Note that the result of this method is immediately outdated. If this
method indicates the file exists then there is no guarantee that a
subsequent access will succeed. Care should be taken when using this
method in security sensitive applications.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to test
|
| `options` | `LinkOption`: options indicating how symbolic links are handled .
|
| Returns ||
|---|---|
| `boolean` | `true` if the file exists; `false` if the file does not exist or its existence cannot be determined.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` is invoked to check read access to the file. |
**See also:**
- `https://developer.android.com/reference/java/nio/file/Files#notExists(java.nio.file.Path,%20java.nio.file.LinkOption[])`
### find
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Stream find (Path start,
int maxDepth,
BiPredicate matcher,
FileVisitOption... options)
```
Return a `Stream` that is lazily populated with `Path` by searching for files in a file tree rooted at a given starting
file.
This method walks the file tree in exactly the manner specified by
the `https://developer.android.com/reference/java/nio/file/Files#walk(java.nio.file.Path,%20int,%20java.nio.file.FileVisitOption[])` method. For each file encountered, the given
`https://developer.android.com/reference/java/util/function/BiPredicate` is invoked with its `https://developer.android.com/reference/java/nio/file/Path` and `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes`. The `Path` object is obtained as if by
`https://developer.android.com/reference/java/nio/file/Path#resolve(java.nio.file.Path)` the relative path against `start` and is only included in the returned `https://developer.android.com/reference/java/util/stream/Stream` if
the `BiPredicate` returns true. Compare to calling `https://developer.android.com/reference/java/util/stream/Stream#filter(java.util.function.Predicate)` on the `Stream`
returned by `walk` method, this method may be more efficient by
avoiding redundant retrieval of the `BasicFileAttributes`.
The returned stream contains references to one or more open directories.
The directories are closed by closing the stream.
If an `https://developer.android.com/reference/java/io/IOException` is thrown when accessing the directory
after returned from this method, it is wrapped in an `https://developer.android.com/reference/java/io/UncheckedIOException` which will be thrown from the method that caused
the access to take place.
##### API Note:
- This method must be used within a try-with-resources statement or similar control structure to ensure that the stream's open directories are closed promptly after the stream's operations have completed.
| Parameters ||
|---|---|
| `start` | `Path`: the starting file
|
| `maxDepth` | `int`: the maximum number of directory levels to search
|
| `matcher` | `BiPredicate`: the function used to decide whether a file should be included in the returned stream
|
| `options` | `FileVisitOption`: options to configure the traversal
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/stream/Stream` | the `https://developer.android.com/reference/java/util/stream/Stream` of `https://developer.android.com/reference/java/nio/file/Path`
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error is thrown when accessing the starting file. |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the `maxDepth` parameter is negative |
| `https://developer.android.com/reference/java/lang/SecurityException` | If the security manager denies access to the starting file. In the case of the default provider, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the directory. |
**See also:**
- `https://developer.android.com/reference/java/nio/file/Files#walk(java.nio.file.Path,%20int,%20java.nio.file.FileVisitOption[])`
### getAttribute
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Object getAttribute (Path path,
String attribute,
LinkOption... options)
```
Reads the value of a file attribute.
The `attribute` parameter identifies the attribute to be read
and takes the form:
> \[*view-name***:** \]*attribute-name*
where square brackets \[...\] delineate an optional component and the character `':'` stands for itself.
*view-name* is the `https://developer.android.com/reference/java/nio/file/attribute/AttributeView#name()` of a `https://developer.android.com/reference/java/nio/file/attribute/FileAttributeView` that identifies a set of file attributes. If not
specified then it defaults to `"basic"`, the name of the file
attribute view that identifies the basic set of file attributes common to
many file systems. *attribute-name* is the name of the attribute.
The `options` array may be used to indicate how symbolic links
are handled for the case that the file is a symbolic link. By default,
symbolic links are followed and the file attribute of the final target
of the link is read. If the option `https://developer.android.com/reference/java/nio/file/LinkOption#NOFOLLOW_LINKS` is present then symbolic links are not followed.
**Usage Example:**
Suppose we require the user ID of the file owner on a system that
supports a "`unix`" view:
```
Path path = ...
int uid = (Integer)Files.getAttribute(path, "unix:uid");
```
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `attribute` | `String`: the attribute to read
|
| `options` | `LinkOption`: options indicating how symbolic links are handled
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Object` | the attribute value
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the attribute name is not specified or is not recognized |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, its `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method denies read access to the file. If this method is invoked to read security sensitive attributes then the security manager may be invoked to check for additional permissions. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the attribute view is not available |
### getFileAttributeView
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static V getFileAttributeView (Path path,
Class type,
LinkOption... options)
```
Returns a file attribute view of a given type.
A file attribute view provides a read-only or updatable view of a
set of file attributes. This method is intended to be used where the file
attribute view defines type-safe methods to read or update the file
attributes. The `type` parameter is the type of the attribute view
required and the method returns an instance of that type if supported.
The `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributeView` type supports access to the basic
attributes of a file. Invoking this method to select a file attribute
view of that type will always return an instance of that class.
The `options` array may be used to indicate how symbolic links
are handled by the resulting file attribute view for the case that the
file is a symbolic link. By default, symbolic links are followed. If the
option `https://developer.android.com/reference/java/nio/file/LinkOption#NOFOLLOW_LINKS` is present then
symbolic links are not followed. This option is ignored by implementations
that do not support symbolic links.
**Usage Example:**
Suppose we want read or set a file's ACL, if supported:
```
Path path = ...
AclFileAttributeView view = Files.getFileAttributeView(path, AclFileAttributeView.class);
if (view != null) {
List acl = view.getAcl();
:
}
```
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `type` | `Class`: the `Class` object corresponding to the file attribute view
|
| `options` | `LinkOption`: options indicating how symbolic links are handled
|
| Returns ||
|---|---|
| `V` | a file attribute view of the specified type, or `null` if the attribute view type is not available
|
### getFileStore
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static FileStore getFileStore (Path path)
```
Returns the `https://developer.android.com/reference/java/nio/file/FileStore` representing the file store where a file
is located.
Once a reference to the `FileStore` is obtained it is
implementation specific if operations on the returned `FileStore`,
or `https://developer.android.com/reference/java/nio/file/attribute/FileStoreAttributeView` objects obtained from it, continue
to depend on the existence of the file. In particular the behavior is not
defined for the case that the file is deleted or moved to a different
file store.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/FileStore` | the file store where the file is stored
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file, and in addition it checks `https://developer.android.com/reference/java/lang/RuntimePermission``("getFileStoreAttributes")` |
### getLastModifiedTime
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static FileTime getLastModifiedTime (Path path,
LinkOption... options)
```
Returns a file's last modified time.
The `options` array may be used to indicate how symbolic links
are handled for the case that the file is a symbolic link. By default,
symbolic links are followed and the file attribute of the final target
of the link is read. If the option `https://developer.android.com/reference/java/nio/file/LinkOption#NOFOLLOW_LINKS` is present then symbolic links are not followed.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `options` | `LinkOption`: options indicating how symbolic links are handled
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/attribute/FileTime` | a `FileTime` representing the time the file was last modified, or an implementation specific default when a time stamp to indicate the time of last modification is not supported by the file system
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, its `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method denies read access to the file. |
**See also:**
- `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes#lastModifiedTime()`
### getOwner
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static UserPrincipal getOwner (Path path,
LinkOption... options)
```
Returns the owner of a file.
The `path` parameter is associated with a file system that
supports `https://developer.android.com/reference/java/nio/file/attribute/FileOwnerAttributeView`. This file attribute view provides
access to a file attribute that is the owner of the file.
| Parameters ||
|---|---|
| `path` | `Path`: The path to the file
|
| `options` | `LinkOption`: options indicating how symbolic links are handled
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/attribute/UserPrincipal` | A user principal representing the owner of the file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, it denies `https://developer.android.com/reference/java/lang/RuntimePermission``("accessUserInformation")` or its `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method denies read access to the file. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the associated file system does not support the `FileOwnerAttributeView` |
### getPosixFilePermissions
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Set getPosixFilePermissions (Path path,
LinkOption... options)
```
Returns a file's POSIX file permissions.
The `path` parameter is associated with a `FileSystem`
that supports the `https://developer.android.com/reference/java/nio/file/attribute/PosixFileAttributeView`. This attribute view
provides access to file attributes commonly associated with files on file
systems used by operating systems that implement the Portable Operating
System Interface (POSIX) family of standards.
The `options` array may be used to indicate how symbolic links
are handled for the case that the file is a symbolic link. By default,
symbolic links are followed and the file attribute of the final target
of the link is read. If the option `https://developer.android.com/reference/java/nio/file/LinkOption#NOFOLLOW_LINKS` is present then symbolic links are not followed.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `options` | `LinkOption`: options indicating how symbolic links are handled
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/Set` | the file permissions
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, a security manager is installed, and it denies `https://developer.android.com/reference/java/lang/RuntimePermission``("accessUserInformation")` or its `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method denies read access to the file. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the associated file system does not support the `PosixFileAttributeView` |
### isDirectory
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static boolean isDirectory (Path path,
LinkOption... options)
```
Tests whether a file is a directory.
The `options` array may be used to indicate how symbolic links
are handled for the case that the file is a symbolic link. By default,
symbolic links are followed and the file attribute of the final target
of the link is read. If the option `https://developer.android.com/reference/java/nio/file/LinkOption#NOFOLLOW_LINKS` is present then symbolic links are not followed.
Where it is required to distinguish an I/O exception from the case
that the file is not a directory then the file attributes can be
read with the `https://developer.android.com/reference/java/nio/file/Files#readAttributes(java.nio.file.Path,%20java.lang.Class,%20java.nio.file.LinkOption[])` method and the file type tested with the `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes#isDirectory()` method.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to test
|
| `options` | `LinkOption`: options indicating how symbolic links are handled
|
| Returns ||
|---|---|
| `boolean` | `true` if the file is a directory; `false` if the file does not exist, is not a directory, or it cannot be determined if the file is a directory or not.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, its `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method denies read access to the file. |
### isExecutable
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static boolean isExecutable (Path path)
```
Tests whether a file is executable. This method checks that a file exists
and that this Java virtual machine has appropriate privileges to `https://developer.android.com/reference/java/lang/Runtime#exec(java.lang.String)` the file. The semantics may differ when checking
access to a directory. For example, on UNIX systems, checking for
execute access checks that the Java virtual machine has permission to
search the directory in order to access file or subdirectories.
Depending on the implementation, this method may require to read file
permissions, access control lists, or other file attributes in order to
check the effective access to the file. Consequently, this method may not
be atomic with respect to other file system operations.
Note that the result of this method is immediately outdated, there is
no guarantee that a subsequent attempt to execute the file will succeed
(or even that it will access the same file). Care should be taken when
using this method in security sensitive applications.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to check
|
| Returns ||
|---|---|
| `boolean` | `true` if the file exists and is executable; `false` if the file does not exist, execute access would be denied because the Java virtual machine has insufficient privileges, or access cannot be determined
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkExec(java.lang.String)` is invoked to check execute access to the file. |
### isHidden
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static boolean isHidden (Path path)
```
Tells whether or not a file is considered *hidden* . The exact
definition of hidden is platform or provider dependent. On UNIX for
example a file is considered to be hidden if its name begins with a
period character ('.'). On Windows a file is considered hidden if it
isn't a directory and the DOS `https://developer.android.com/reference/java/nio/file/attribute/DosFileAttributes#isHidden()`
attribute is set.
Depending on the implementation this method may require to access
the file system to determine if the file is considered hidden.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to test
|
| Returns ||
|---|---|
| `boolean` | `true` if the file is considered hidden
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file. |
### isReadable
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static boolean isReadable (Path path)
```
Tests whether a file is readable. This method checks that a file exists
and that this Java virtual machine has appropriate privileges that would
allow it open the file for reading. Depending on the implementation, this
method may require to read file permissions, access control lists, or
other file attributes in order to check the effective access to the file.
Consequently, this method may not be atomic with respect to other file
system operations.
Note that the result of this method is immediately outdated, there is
no guarantee that a subsequent attempt to open the file for reading will
succeed (or even that it will access the same file). Care should be taken
when using this method in security sensitive applications.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to check
|
| Returns ||
|---|---|
| `boolean` | `true` if the file exists and is readable; `false` if the file does not exist, read access would be denied because the Java virtual machine has insufficient privileges, or access cannot be determined
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` is invoked to check read access to the file. |
### isRegularFile
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static boolean isRegularFile (Path path,
LinkOption... options)
```
Tests whether a file is a regular file with opaque content.
The `options` array may be used to indicate how symbolic links
are handled for the case that the file is a symbolic link. By default,
symbolic links are followed and the file attribute of the final target
of the link is read. If the option `https://developer.android.com/reference/java/nio/file/LinkOption#NOFOLLOW_LINKS` is present then symbolic links are not followed.
Where it is required to distinguish an I/O exception from the case
that the file is not a regular file then the file attributes can be
read with the `https://developer.android.com/reference/java/nio/file/Files#readAttributes(java.nio.file.Path,%20java.lang.Class,%20java.nio.file.LinkOption[])` method and the file type tested with the `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes#isRegularFile()` method.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `options` | `LinkOption`: options indicating how symbolic links are handled
|
| Returns ||
|---|---|
| `boolean` | `true` if the file is a regular file; `false` if the file does not exist, is not a regular file, or it cannot be determined if the file is a regular file or not.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, its `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method denies read access to the file. |
### isSameFile
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static boolean isSameFile (Path path,
Path path2)
```
Tests if two paths locate the same file.
If both `Path` objects are `https://developer.android.com/reference/java/nio/file/Path#equals(java.lang.Object)`
then this method returns `true` without checking if the file exists.
If the two `Path` objects are associated with different providers
then this method returns `false`. Otherwise, this method checks if
both `Path` objects locate the same file, and depending on the
implementation, may require to open or access both files.
If the file system and files remain static, then this method implements
an equivalence relation for non-null `Paths`.
- It is *reflexive*: for `Path` `f`, `isSameFile(f,f)` should return `true`.
- It is *symmetric*: for two `Paths` `f` and `g`, `isSameFile(f,g)` will equal `isSameFile(g,f)`.
- It is *transitive*: for three `Paths` `f`, `g`, and `h`, if `isSameFile(f,g)` returns `true` and `isSameFile(g,h)` returns `true`, then `isSameFile(f,h)` will return `true`.
| Parameters ||
|---|---|
| `path` | `Path`: one path to the file
|
| `path2` | `Path`: the other path
|
| Returns ||
|---|---|
| `boolean` | `true` if, and only if, the two paths locate the same file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to both files. |
**See also:**
- `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes#fileKey()`
### isSymbolicLink
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static boolean isSymbolicLink (Path path)
```
Tests whether a file is a symbolic link.
Where it is required to distinguish an I/O exception from the case
that the file is not a symbolic link then the file attributes can be
read with the `https://developer.android.com/reference/java/nio/file/Files#readAttributes(java.nio.file.Path,%20java.lang.Class,%20java.nio.file.LinkOption[])` method and the file type tested with the `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes#isSymbolicLink()` method.
| Parameters ||
|---|---|
| `path` | `Path`: The path to the file
|
| Returns ||
|---|---|
| `boolean` | `true` if the file is a symbolic link; `false` if the file does not exist, is not a symbolic link, or it cannot be determined if the file is a symbolic link or not.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, its `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method denies read access to the file. |
### isWritable
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static boolean isWritable (Path path)
```
Tests whether a file is writable. This method checks that a file exists
and that this Java virtual machine has appropriate privileges that would
allow it open the file for writing. Depending on the implementation, this
method may require to read file permissions, access control lists, or
other file attributes in order to check the effective access to the file.
Consequently, this method may not be atomic with respect to other file
system operations.
Note that result of this method is immediately outdated, there is no
guarantee that a subsequent attempt to open the file for writing will
succeed (or even that it will access the same file). Care should be taken
when using this method in security sensitive applications.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to check
|
| Returns ||
|---|---|
| `boolean` | `true` if the file exists and is writable; `false` if the file does not exist, write access would be denied because the Java virtual machine has insufficient privileges, or access cannot be determined
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` is invoked to check write access to the file. |
### lines
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Stream lines (Path path)
```
Read all lines from a file as a `Stream`. Bytes from the file are
decoded into characters using the `https://developer.android.com/reference/java/nio/charset/StandardCharsets#UTF_8`
`https://developer.android.com/reference/java/nio/charset/Charset`.
The returned stream contains a reference to an open file. The file
is closed by closing the stream.
The file contents should not be modified during the execution of the
terminal stream operation. Otherwise, the result of the terminal stream
operation is undefined.
This method works as if invoking it were equivalent to evaluating the
expression:
Files.lines(path, StandardCharsets.UTF_8)
##### API Note:
- This method must be used within a try-with-resources statement or similar control structure to ensure that the stream's open file is closed promptly after the stream's operations have completed.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/stream/Stream` | the lines from the file as a `Stream`
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs opening the file |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file. |
### lines
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Stream lines (Path path,
Charset cs)
```
Read all lines from a file as a `Stream`. Unlike `https://developer.android.com/reference/java/nio/file/Files#readAllLines(java.nio.file.Path,%20java.nio.charset.Charset)`, this method does not read
all lines into a `List`, but instead populates lazily as the stream
is consumed.
Bytes from the file are decoded into characters using the specified
charset and the same line terminators as specified by `readAllLines` are supported.
The returned stream contains a reference to an open file. The file
is closed by closing the stream.
The file contents should not be modified during the execution of the
terminal stream operation. Otherwise, the result of the terminal stream
operation is undefined.
After this method returns, then any subsequent I/O exception that
occurs while reading from the file or when a malformed or unmappable byte
sequence is read, is wrapped in an `https://developer.android.com/reference/java/io/UncheckedIOException` that will
be thrown from the
`https://developer.android.com/reference/java/util/stream/Stream` method that caused the read to take
place. In case an `IOException` is thrown when closing the file,
it is also wrapped as an `UncheckedIOException`.
##### API Note:
- This method must be used within a try-with-resources statement or similar control structure to ensure that the stream's open file is closed promptly after the stream's operations have completed.
##### Implementation Note:
- This implementation supports good parallel stream performance for the standard charsets `https://developer.android.com/reference/java/nio/charset/StandardCharsets#UTF_8`, `https://developer.android.com/reference/java/nio/charset/StandardCharsets#US_ASCII` and `https://developer.android.com/reference/java/nio/charset/StandardCharsets#ISO_8859_1`. Such *line-optimal* charsets have the property that the encoded bytes of a line feed ('\\n') or a carriage return ('\\r') are efficiently identifiable from other encoded characters when randomly accessing the bytes of the file.
For non-*line-optimal* charsets the stream source's
spliterator has poor splitting properties, similar to that of a
spliterator associated with an iterator or that associated with a stream
returned from `https://developer.android.com/reference/java/io/BufferedReader#lines()`. Poor splitting properties
can result in poor parallel stream performance.
For *line-optimal* charsets the stream source's spliterator
has good splitting properties, assuming the file contains a regular
sequence of lines. Good splitting properties can result in good parallel
stream performance. The spliterator for a *line-optimal* charset
takes advantage of the charset properties (a line feed or a carriage
return being efficient identifiable) such that when splitting it can
approximately divide the number of covered lines in half.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `cs` | `Charset`: the charset to use for decoding
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/stream/Stream` | the lines from the file as a `Stream`
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs opening the file |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file. |
**See also:**
- `https://developer.android.com/reference/java/nio/file/Files#readAllLines(java.nio.file.Path,%20java.nio.charset.Charset)`
- `https://developer.android.com/reference/java/nio/file/Files#newBufferedReader(java.nio.file.Path,%20java.nio.charset.Charset)`
- `https://developer.android.com/reference/java/io/BufferedReader#lines()`
### list
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Stream list (Path dir)
```
Return a lazily populated `Stream`, the elements of
which are the entries in the directory. The listing is not recursive.
The elements of the stream are `https://developer.android.com/reference/java/nio/file/Path` objects that are
obtained as if by `https://developer.android.com/reference/java/nio/file/Path#resolve(java.nio.file.Path)` the name of the
directory entry against `dir`. Some file systems maintain special
links to the directory itself and the directory's parent directory.
Entries representing these links are not included.
The stream is *weakly consistent*. It is thread safe but does
not freeze the directory while iterating, so it may (or may not)
reflect updates to the directory that occur after returning from this
method.
The returned stream contains a reference to an open directory.
The directory is closed by closing the stream.
Operating on a closed stream behaves as if the end of stream
has been reached. Due to read-ahead, one or more elements may be
returned after the stream has been closed.
If an `https://developer.android.com/reference/java/io/IOException` is thrown when accessing the directory
after this method has returned, it is wrapped in an `https://developer.android.com/reference/java/io/UncheckedIOException` which will be thrown from the method that caused
the access to take place.
##### API Note:
- This method must be used within a try-with-resources statement or similar control structure to ensure that the stream's open directory is closed promptly after the stream's operations have completed.
| Parameters ||
|---|---|
| `dir` | `Path`: The path to the directory
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/stream/Stream` | The `Stream` describing the content of the directory
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs when opening the directory |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the directory. |
| `https://developer.android.com/reference/java/nio/file/NotDirectoryException` | if the file could not otherwise be opened because it is not a directory *(optional specific exception)* |
**See also:**
- `https://developer.android.com/reference/java/nio/file/Files#newDirectoryStream(java.nio.file.Path)`
### move
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path move (Path source,
Path target,
CopyOption... options)
```
Move or rename a file to a target file.
By default, this method attempts to move the file to the target
file, failing if the target file exists except if the source and
target are the `https://developer.android.com/reference/java/nio/file/Files#isSameFile(java.nio.file.Path,%20java.nio.file.Path)` file, in which case this method
has no effect. If the file is a symbolic link then the symbolic link
itself, not the target of the link, is moved. This method may be
invoked to move an empty directory. In some implementations a directory
has entries for special files or links that are created when the
directory is created. In such implementations a directory is considered
empty when only the special entries exist. When invoked to move a
directory that is not empty then the directory is moved if it does not
require moving the entries in the directory. For example, renaming a
directory on the same `https://developer.android.com/reference/java/nio/file/FileStore` will usually not require moving
the entries in the directory. When moving a directory requires that its
entries be moved then this method fails (by throwing an `IOException`). To move a *file tree* may involve copying rather
than moving directories and this can be done using the `https://developer.android.com/reference/java/nio/file/Files#copy(java.io.InputStream,%20java.nio.file.Path,%20java.nio.file.CopyOption[])` method in conjunction with the `https://developer.android.com/reference/java/nio/file/Files#walkFileTree(java.nio.file.Path,%20java.nio.file.FileVisitor)` utility method.
The `options` parameter may include any of the following:
| Option | Description |
| `https://developer.android.com/reference/java/nio/file/StandardCopyOption#REPLACE_EXISTING` | If the target file exists, then the target file is replaced if it is not a non-empty directory. If the target file exists and is a symbolic link, then the symbolic link itself, not the target of the link, is replaced. |
| `https://developer.android.com/reference/java/nio/file/StandardCopyOption#ATOMIC_MOVE` | The move is performed as an atomic file system operation and all other options are ignored. If the target file exists then it is implementation specific if the existing file is replaced or this method fails by throwing an `https://developer.android.com/reference/java/io/IOException`. If the move cannot be performed as an atomic file system operation then `https://developer.android.com/reference/java/nio/file/AtomicMoveNotSupportedException` is thrown. This can arise, for example, when the target location is on a different `FileStore` and would require that the file be copied, or target location is associated with a different provider to this object. |
|---|---|
[Options]
An implementation of this interface may support additional
implementation specific options.
Moving a file will copy the `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes#lastModifiedTime()` to the target
file if supported by both source and target file stores. Copying of file
timestamps may result in precision loss. An implementation may also
attempt to copy other file attributes but is not required to fail if the
file attributes cannot be copied. When the move is performed as
a non-atomic operation, and an `IOException` is thrown, then the
state of the files is not defined. The original file and the target file
may both exist, the target file may be incomplete or some of its file
attributes may not been copied from the original file.
**Usage Examples:**
Suppose we want to rename a file to "newname", keeping the file in the
same directory:
```
Path source = ...
Files.move(source, source.resolveSibling("newname"));
```
Alternatively, suppose we want to move a file to new directory, keeping the same file name, and replacing any existing file of that name in the directory:
```
Path source = ...
Path newdir = ...
Files.move(source, newdir.resolve(source.getFileName()), REPLACE_EXISTING);
```
| Parameters ||
|---|---|
| `source` | `Path`: the path to the file to move
|
| `target` | `Path`: the path to the target file (may be associated with a different provider to the source path)
|
| `options` | `CopyOption`: options specifying how the move should be done
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the path to the target file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to both the source and target file. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the array contains a copy option that is not supported |
| `https://developer.android.com/reference/java/nio/file/AtomicMoveNotSupportedException` | if the options array contains the `ATOMIC_MOVE` option but the file cannot be moved as an atomic file system operation. |
| `https://developer.android.com/reference/java/nio/file/DirectoryNotEmptyException` | the `REPLACE_EXISTING` option is specified but the file cannot be replaced because it is a non-empty directory, or the source is a non-empty directory containing entries that would be required to be moved *(optional specific exceptions)* |
| `https://developer.android.com/reference/java/nio/file/FileAlreadyExistsException` | if the target file exists but cannot be replaced because the `REPLACE_EXISTING` option is not specified *(optional specific exception)* |
### newBufferedReader
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static BufferedReader newBufferedReader (Path path,
Charset cs)
```
Opens a file for reading, returning a `BufferedReader` that may be
used to read text from the file in an efficient manner. Bytes from the
file are decoded into characters using the specified charset. Reading
commences at the beginning of the file.
The `Reader` methods that read from the file throw `IOException` if a malformed or unmappable byte sequence is read.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `cs` | `Charset`: the charset to use for decoding
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/io/BufferedReader` | a new buffered reader, with default buffer size, to read text from the file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs opening the file |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file. |
**See also:**
- `https://developer.android.com/reference/java/nio/file/Files#readAllLines(java.nio.file.Path)`
### newBufferedReader
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static BufferedReader newBufferedReader (Path path)
```
Opens a file for reading, returning a `BufferedReader` to read text
from the file in an efficient manner. Bytes from the file are decoded into
characters using the `https://developer.android.com/reference/java/nio/charset/StandardCharsets#UTF_8` `https://developer.android.com/reference/java/nio/charset/Charset`.
This method works as if invoking it were equivalent to evaluating the
expression:
Files.newBufferedReader(path, StandardCharsets.UTF_8)
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/io/BufferedReader` | a new buffered reader, with default buffer size, to read text from the file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs opening the file |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file. |
### newBufferedWriter
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static BufferedWriter newBufferedWriter (Path path,
Charset cs,
OpenOption... options)
```
Opens or creates a file for writing, returning a `BufferedWriter`
that may be used to write text to the file in an efficient manner.
The `options` parameter specifies how the file is created or
opened. If no options are present then this method works as if the `https://developer.android.com/reference/java/nio/file/StandardOpenOption#CREATE`, `https://developer.android.com/reference/java/nio/file/StandardOpenOption#TRUNCATE_EXISTING`, and `https://developer.android.com/reference/java/nio/file/StandardOpenOption#WRITE` options are present. In other words, it
opens the file for writing, creating the file if it doesn't exist, or
initially truncating an existing `https://developer.android.com/reference/java/nio/file/Files#isRegularFile(java.nio.file.Path,%20java.nio.file.LinkOption[])` to
a size of `0` if it exists.
The `Writer` methods to write text throw `IOException`
if the text cannot be encoded using the specified charset.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `cs` | `Charset`: the charset to use for encoding
|
| `options` | `OpenOption`: options specifying how the file is opened
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/io/BufferedWriter` | a new buffered writer, with default buffer size, to write text to the file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs opening or creating the file |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if `options` contains an invalid combination of options |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the file. The `https://developer.android.com/reference/java/lang/SecurityManager#checkDelete(java.lang.String)` method is invoked to check delete access if the file is opened with the `DELETE_ON_CLOSE` option. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if an unsupported option is specified |
**See also:**
- `https://developer.android.com/reference/java/nio/file/Files#write(java.nio.file.Path,%20java.lang.Iterable,%20java.nio.charset.Charset,%20java.nio.file.OpenOption[])`
### newBufferedWriter
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static BufferedWriter newBufferedWriter (Path path,
OpenOption... options)
```
Opens or creates a file for writing, returning a `BufferedWriter`
to write text to the file in an efficient manner. The text is encoded
into bytes for writing using the `https://developer.android.com/reference/java/nio/charset/StandardCharsets#UTF_8`
`https://developer.android.com/reference/java/nio/charset/Charset`.
This method works as if invoking it were equivalent to evaluating the
expression:
Files.newBufferedWriter(path, StandardCharsets.UTF_8, options)
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `options` | `OpenOption`: options specifying how the file is opened
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/io/BufferedWriter` | a new buffered writer, with default buffer size, to write text to the file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs opening or creating the file |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if `options` contains an invalid combination of options |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the file. The `https://developer.android.com/reference/java/lang/SecurityManager#checkDelete(java.lang.String)` method is invoked to check delete access if the file is opened with the `DELETE_ON_CLOSE` option. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if an unsupported option is specified |
### newByteChannel
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static SeekableByteChannel newByteChannel (Path path,
Set options,
FileAttribute... attrs)
```
Opens or creates a file, returning a seekable byte channel to access the
file.
The `options` parameter determines how the file is opened.
The `https://developer.android.com/reference/java/nio/file/StandardOpenOption#READ` and `https://developer.android.com/reference/java/nio/file/StandardOpenOption#WRITE` options determine if the file should be
opened for reading and/or writing. If neither option (or the `https://developer.android.com/reference/java/nio/file/StandardOpenOption#APPEND` option) is present then the file is
opened for reading. By default reading or writing commence at the
beginning of the file.
In the addition to `READ` and `WRITE`, the following
options may be present:
| Option | Description |
| `https://developer.android.com/reference/java/nio/file/StandardOpenOption#APPEND` | If this option is present then the file is opened for writing and each invocation of the channel's `write` method first advances the position to the end of the file and then writes the requested data. Whether the advancement of the position and the writing of the data are done in a single atomic operation is system-dependent and therefore unspecified. This option may not be used in conjunction with the `READ` or `TRUNCATE_EXISTING` options. |
| `https://developer.android.com/reference/java/nio/file/StandardOpenOption#TRUNCATE_EXISTING` | If this option is present then the existing file is truncated to a size of 0 bytes. This option is ignored when the file is opened only for reading. |
| `https://developer.android.com/reference/java/nio/file/StandardOpenOption#CREATE_NEW` | If this option is present then a new file is created, failing if the file already exists or is a symbolic link. When creating a file the check for the existence of the file and the creation of the file if it does not exist is atomic with respect to other file system operations. This option is ignored when the file is opened only for reading. |
| `https://developer.android.com/reference/java/nio/file/StandardOpenOption#CREATE` | If this option is present then an existing file is opened if it exists, otherwise a new file is created. This option is ignored if the `CREATE_NEW` option is also present or the file is opened only for reading. |
| `https://developer.android.com/reference/java/nio/file/StandardOpenOption#DELETE_ON_CLOSE` | When this option is present then the implementation makes a *best effort* attempt to delete the file when closed by the `https://developer.android.com/reference/java/nio/channels/Channel#close()` method. If the `close` method is not invoked then a *best effort* attempt is made to delete the file when the Java virtual machine terminates. |
| `https://developer.android.com/reference/java/nio/file/StandardOpenOption#SPARSE` | When creating a new file this option is a *hint* that the new file will be sparse. This option is ignored when not creating a new file. |
| `https://developer.android.com/reference/java/nio/file/StandardOpenOption#SYNC` | Requires that every update to the file's content or metadata be written synchronously to the underlying storage device. (see [Synchronized I/O file integrity](https://developer.android.com/reference/java/nio/file/package-summary#integrity)). |
| `https://developer.android.com/reference/java/nio/file/StandardOpenOption#DSYNC` | Requires that every update to the file's content be written synchronously to the underlying storage device. (see [Synchronized I/O file integrity](https://developer.android.com/reference/java/nio/file/package-summary#integrity)). |
|---|---|
[Options]
An implementation may also support additional implementation specific
options.
The `attrs` parameter is optional `https://developer.android.com/reference/java/nio/file/attribute/FileAttribute` to set atomically when a new file is created.
In the case of the default provider, the returned seekable byte channel
is a `https://developer.android.com/reference/java/nio/channels/FileChannel`.
**Usage Examples:**
Path path = ...
// open file for reading
ReadableByteChannel rbc = Files.newByteChannel(path, EnumSet.of(READ)));
// open file for writing to the end of an existing file, creating
// the file if it doesn't already exist
WritableByteChannel wbc = Files.newByteChannel(path, EnumSet.of(CREATE,APPEND));
// create file with initial permissions, opening it for both reading and writing
FileAttribute> perms = ...
SeekableByteChannel sbc =
Files.newByteChannel(path, EnumSet.of(CREATE_NEW,READ,WRITE), perms);
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to open or create
|
| `options` | `Set`: options specifying how the file is opened
|
| `attrs` | `FileAttribute`: an optional list of file attributes to set atomically when creating the file
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/channels/SeekableByteChannel` | a new seekable byte channel
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the set contains an invalid combination of options |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the path if the file is opened for reading. The `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the path if the file is opened for writing. The `https://developer.android.com/reference/java/lang/SecurityManager#checkDelete(java.lang.String)` method is invoked to check delete access if the file is opened with the `DELETE_ON_CLOSE` option. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if an unsupported open option is specified or the array contains attributes that cannot be set atomically when creating the file |
| `https://developer.android.com/reference/java/nio/file/FileAlreadyExistsException` | if a file of that name already exists and the `https://developer.android.com/reference/java/nio/file/StandardOpenOption#CREATE_NEW` option is specified *(optional specific exception)* |
**See also:**
- `https://developer.android.com/reference/java/nio/channels/FileChannel#open(java.nio.file.Path,%20java.util.Set,%20java.nio.file.attribute.FileAttribute[])`
### newByteChannel
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static SeekableByteChannel newByteChannel (Path path,
OpenOption... options)
```
Opens or creates a file, returning a seekable byte channel to access the
file.
This method opens or creates a file in exactly the manner specified
by the `https://developer.android.com/reference/java/nio/file/Files#newByteChannel(java.nio.file.Path,%20java.util.Set,%20java.nio.file.attribute.FileAttribute[])`
method.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to open or create
|
| `options` | `OpenOption`: options specifying how the file is opened
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/channels/SeekableByteChannel` | a new seekable byte channel
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the set contains an invalid combination of options |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the path if the file is opened for reading. The `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the path if the file is opened for writing. The `https://developer.android.com/reference/java/lang/SecurityManager#checkDelete(java.lang.String)` method is invoked to check delete access if the file is opened with the `DELETE_ON_CLOSE` option. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if an unsupported open option is specified |
| `https://developer.android.com/reference/java/nio/file/FileAlreadyExistsException` | if a file of that name already exists and the `https://developer.android.com/reference/java/nio/file/StandardOpenOption#CREATE_NEW` option is specified *(optional specific exception)* |
**See also:**
- `https://developer.android.com/reference/java/nio/channels/FileChannel#open(java.nio.file.Path,%20java.nio.file.OpenOption[])`
### newDirectoryStream
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static DirectoryStream newDirectoryStream (Path dir,
String glob)
```
Opens a directory, returning a `https://developer.android.com/reference/java/nio/file/DirectoryStream` to iterate over
the entries in the directory. The elements returned by the directory
stream's `https://developer.android.com/reference/java/nio/file/DirectoryStream#iterator()` are of type `Path`, each one representing an entry in the directory. The `Path`
objects are obtained as if by `https://developer.android.com/reference/java/nio/file/Path#resolve(java.nio.file.Path)` the
name of the directory entry against `dir`. The entries returned by
the iterator are filtered by matching the `String` representation
of their file names against the given *globbing* pattern.
For example, suppose we want to iterate over the files ending with
".java" in a directory:
```
Path dir = ...
try (DirectoryStream stream = Files.newDirectoryStream(dir, "*.java")) {
:
}
```
The globbing pattern is specified by the `https://developer.android.com/reference/java/nio/file/FileSystem#getPathMatcher(java.lang.String)` method.
When not using the try-with-resources construct, then directory
stream's `close` method should be invoked after iteration is
completed so as to free any resources held for the open directory.
When an implementation supports operations on entries in the
directory that execute in a race-free manner then the returned directory
stream is a `https://developer.android.com/reference/java/nio/file/SecureDirectoryStream`.
| Parameters ||
|---|---|
| `dir` | `Path`: the path to the directory
|
| `glob` | `String`: the glob pattern
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/DirectoryStream` | a new and open `DirectoryStream` object
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the directory. |
| `https://developer.android.com/reference/java/nio/file/NotDirectoryException` | if the file could not otherwise be opened because it is not a directory *(optional specific exception)* |
| `https://developer.android.com/reference/java/util/regex/PatternSyntaxException` | if the pattern is invalid |
### newDirectoryStream
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static DirectoryStream newDirectoryStream (Path dir,
Filter filter)
```
Opens a directory, returning a `https://developer.android.com/reference/java/nio/file/DirectoryStream` to iterate over
the entries in the directory. The elements returned by the directory
stream's `https://developer.android.com/reference/java/nio/file/DirectoryStream#iterator()` are of type `Path`, each one representing an entry in the directory. The `Path`
objects are obtained as if by `https://developer.android.com/reference/java/nio/file/Path#resolve(java.nio.file.Path)` the
name of the directory entry against `dir`. The entries returned by
the iterator are filtered by the given `https://developer.android.com/reference/java/nio/file/DirectoryStream.Filter`.
When not using the try-with-resources construct, then directory
stream's `close` method should be invoked after iteration is
completed so as to free any resources held for the open directory.
Where the filter terminates due to an uncaught error or runtime
exception then it is propagated to the `https://developer.android.com/reference/java/util/Iterator#hasNext()` or `https://developer.android.com/reference/java/util/Iterator#next()` method. Where an `IOException` is thrown, it results in the `hasNext` or `next` method throwing a `https://developer.android.com/reference/java/nio/file/DirectoryIteratorException` with the
`IOException` as the cause.
When an implementation supports operations on entries in the
directory that execute in a race-free manner then the returned directory
stream is a `https://developer.android.com/reference/java/nio/file/SecureDirectoryStream`.
**Usage Example:**
Suppose we want to iterate over the files in a directory that are
larger than 8K.
```
DirectoryStream.Filter filter = new DirectoryStream.Filter() {
public boolean accept(Path file) throws IOException {
return (Files.size(file) > 8192L);
}
};
Path dir = ...
try (DirectoryStream stream = Files.newDirectoryStream(dir, filter)) {
:
}
```
| Parameters ||
|---|---|
| `dir` | `Path`: the path to the directory
|
| `filter` | `Filter`: the directory stream filter
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/DirectoryStream` | a new and open `DirectoryStream` object
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the directory. |
| `https://developer.android.com/reference/java/nio/file/NotDirectoryException` | if the file could not otherwise be opened because it is not a directory *(optional specific exception)* |
### newDirectoryStream
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static DirectoryStream newDirectoryStream (Path dir)
```
Opens a directory, returning a `https://developer.android.com/reference/java/nio/file/DirectoryStream` to iterate over
all entries in the directory. The elements returned by the directory
stream's `https://developer.android.com/reference/java/nio/file/DirectoryStream#iterator()` are of type `Path`, each one representing an entry in the directory. The `Path`
objects are obtained as if by `https://developer.android.com/reference/java/nio/file/Path#resolve(java.nio.file.Path)` the
name of the directory entry against `dir`.
When not using the try-with-resources construct, then directory
stream's `close` method should be invoked after iteration is
completed so as to free any resources held for the open directory.
When an implementation supports operations on entries in the
directory that execute in a race-free manner then the returned directory
stream is a `https://developer.android.com/reference/java/nio/file/SecureDirectoryStream`.
| Parameters ||
|---|---|
| `dir` | `Path`: the path to the directory
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/DirectoryStream` | a new and open `DirectoryStream` object
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the directory. |
| `https://developer.android.com/reference/java/nio/file/NotDirectoryException` | if the file could not otherwise be opened because it is not a directory *(optional specific exception)* |
### newInputStream
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static InputStream newInputStream (Path path,
OpenOption... options)
```
Opens a file, returning an input stream to read from the file. The stream
will not be buffered, and is not required to support the `https://developer.android.com/reference/java/io/InputStream#mark(int)` or `https://developer.android.com/reference/java/io/InputStream#reset()` methods. The
stream will be safe for access by multiple concurrent threads. Reading
commences at the beginning of the file. Whether the returned stream is
*asynchronously closeable* and/or *interruptible* is highly
file system provider specific and therefore not specified.
The `options` parameter determines how the file is opened.
If no options are present then it is equivalent to opening the file with
the `https://developer.android.com/reference/java/nio/file/StandardOpenOption#READ` option. In addition to the `READ` option, an implementation may also support additional implementation
specific options.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to open
|
| `options` | `OpenOption`: options specifying how the file is opened
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/io/InputStream` | a new input stream
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if an invalid combination of options is specified |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if an unsupported option is specified |
### newOutputStream
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static OutputStream newOutputStream (Path path,
OpenOption... options)
```
Opens or creates a file, returning an output stream that may be used to
write bytes to the file. The resulting stream will not be buffered. The
stream will be safe for access by multiple concurrent threads. Whether
the returned stream is *asynchronously closeable* and/or
*interruptible* is highly file system provider specific and
therefore not specified.
This method opens or creates a file in exactly the manner specified
by the `https://developer.android.com/reference/java/nio/file/Files#newByteChannel(java.nio.file.Path,%20java.util.Set,%20java.nio.file.attribute.FileAttribute[])`
method with the exception that the `https://developer.android.com/reference/java/nio/file/StandardOpenOption#READ`
option may not be present in the array of options. If no options are
present then this method works as if the `https://developer.android.com/reference/java/nio/file/StandardOpenOption#CREATE`, `https://developer.android.com/reference/java/nio/file/StandardOpenOption#TRUNCATE_EXISTING`,
and `https://developer.android.com/reference/java/nio/file/StandardOpenOption#WRITE` options are present. In other
words, it opens the file for writing, creating the file if it doesn't
exist, or initially truncating an existing `https://developer.android.com/reference/java/nio/file/Files#isRegularFile(java.nio.file.Path,%20java.nio.file.LinkOption[])` to a size of `0` if it exists.
**Usage Examples:**
```
Path path = ...
// truncate and overwrite an existing file, or create the file if
// it doesn't initially exist
OutputStream out = Files.newOutputStream(path);
// append to an existing file, fail if the file does not exist
out = Files.newOutputStream(path, APPEND);
// append to an existing file, create file if it doesn't initially exist
out = Files.newOutputStream(path, CREATE, APPEND);
// always create new file, failing if it already exists
out = Files.newOutputStream(path, CREATE_NEW);
```
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to open or create
|
| `options` | `OpenOption`: options specifying how the file is opened
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/io/OutputStream` | a new output stream
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if `options` contains an invalid combination of options |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the file. The `https://developer.android.com/reference/java/lang/SecurityManager#checkDelete(java.lang.String)` method is invoked to check delete access if the file is opened with the `DELETE_ON_CLOSE` option. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if an unsupported option is specified |
### notExists
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static boolean notExists (Path path,
LinkOption... options)
```
Tests whether the file located by this path does not exist. This method
is intended for cases where it is required to take action when it can be
confirmed that a file does not exist.
The `options` parameter may be used to indicate how symbolic links
are handled for the case that the file is a symbolic link. By default,
symbolic links are followed. If the option `https://developer.android.com/reference/java/nio/file/LinkOption#NOFOLLOW_LINKS` is present then symbolic links are not followed.
Note that this method is not the complement of the `https://developer.android.com/reference/java/nio/file/Files#exists(java.nio.file.Path,%20java.nio.file.LinkOption[])` method. Where it is not possible to determine if a file exists
or not then both methods return `false`. As with the `exists`
method, the result of this method is immediately outdated. If this
method indicates the file does exist then there is no guarantee that a
subsequent attempt to create the file will succeed. Care should be taken
when using this method in security sensitive applications.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to test
|
| `options` | `LinkOption`: options indicating how symbolic links are handled
|
| Returns ||
|---|---|
| `boolean` | `true` if the file does not exist; `false` if the file exists or its existence cannot be determined
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` is invoked to check read access to the file. |
### probeContentType
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static String probeContentType (Path path)
```
Probes the content type of a file.
This method uses the installed `https://developer.android.com/reference/java/nio/file/spi/FileTypeDetector` implementations
to probe the given file to determine its content type. Each file type
detector's `https://developer.android.com/reference/java/nio/file/spi/FileTypeDetector#probeContentType(java.nio.file.Path)` is
invoked, in turn, to probe the file type. If the file is recognized then
the content type is returned. If the file is not recognized by any of the
installed file type detectors then a system-default file type detector is
invoked to guess the content type.
A given invocation of the Java virtual machine maintains a system-wide
list of file type detectors. Installed file type detectors are loaded
using the service-provider loading facility defined by the `https://developer.android.com/reference/java/util/ServiceLoader`
class. Installed file type detectors are loaded using the system class
loader. If the system class loader cannot be found then the platform class
loader is used. File type detectors are typically installed
by placing them in a JAR file on the application class path,
the JAR file contains a provider-configuration file
named `java.nio.file.spi.FileTypeDetector` in the resource directory
`META-INF/services`, and the file lists one or more fully-qualified
names of concrete subclass of `FileTypeDetector ` that have a zero
argument constructor. If the process of locating or instantiating the
installed file type detectors fails then an unspecified error is thrown.
The ordering that installed providers are located is implementation
specific.
The return value of this method is the string form of the value of a
Multipurpose Internet Mail Extension (MIME) content type as
defined by [*RFC 2045: Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies*](http://www.ietf.org/rfc/rfc2045.txt). The string is guaranteed to be parsable according
to the grammar in the RFC.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file to probe
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/String` | The content type of the file, or `null` if the content type cannot be determined
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | If a security manager is installed and it denies an unspecified permission required by a file type detector implementation. |
### readAllBytes
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static byte[] readAllBytes (Path path)
```
Reads all the bytes from a file. The method ensures that the file is
closed when all bytes have been read or an I/O error, or other runtime
exception, is thrown.
Note that this method is intended for simple cases where it is
convenient to read all bytes into a byte array. It is not intended for
reading in large files.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| Returns ||
|---|---|
| `byte[]` | a byte array containing the bytes read from the file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs reading from the stream |
| `https://developer.android.com/reference/java/lang/OutOfMemoryError` | if an array of the required size cannot be allocated, for example the file is larger that `2GB` |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file. |
### readAllLines
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static List readAllLines (Path path,
Charset cs)
```
Read all lines from a file. This method ensures that the file is
closed when all bytes have been read or an I/O error, or other runtime
exception, is thrown. Bytes from the file are decoded into characters
using the specified charset.
This method recognizes the following as line terminators:
- `\u000D` followed by `\u000A`, CARRIAGE RETURN followed by LINE FEED
- `\u000A`, LINE FEED
- `\u000D`, CARRIAGE RETURN
Additional Unicode line terminators may be recognized in future
releases.
Note that this method is intended for simple cases where it is
convenient to read all lines in a single operation. It is not intended
for reading in large files.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `cs` | `Charset`: the charset to use for decoding
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/List` | the lines from the file as a `List`; whether the `List` is modifiable or not is implementation dependent and therefore not specified
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs reading from the file or a malformed or unmappable byte sequence is read |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file. |
**See also:**
- `https://developer.android.com/reference/java/nio/file/Files#newBufferedReader(java.nio.file.Path)`
### readAllLines
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static List readAllLines (Path path)
```
Read all lines from a file. Bytes from the file are decoded into characters
using the `https://developer.android.com/reference/java/nio/charset/StandardCharsets#UTF_8` `https://developer.android.com/reference/java/nio/charset/Charset`.
This method works as if invoking it were equivalent to evaluating the
expression:
Files.readAllLines(path, StandardCharsets.UTF_8)
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/List` | the lines from the file as a `List`; whether the `List` is modifiable or not is implementation dependent and therefore not specified
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs reading from the file or a malformed or unmappable byte sequence is read |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file. |
### readAttributes
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static A readAttributes (Path path,
Class type,
LinkOption... options)
```
Reads a file's attributes as a bulk operation.
The `type` parameter is the type of the attributes required
and this method returns an instance of that type if supported. All
implementations support a basic set of file attributes and so invoking
this method with a `type` parameter of `BasicFileAttributes.class` will not throw `UnsupportedOperationException`.
The `options` array may be used to indicate how symbolic links
are handled for the case that the file is a symbolic link. By default,
symbolic links are followed and the file attribute of the final target
of the link is read. If the option `https://developer.android.com/reference/java/nio/file/LinkOption#NOFOLLOW_LINKS` is present then symbolic links are not followed.
It is implementation specific if all file attributes are read as an
atomic operation with respect to other file system operations.
**Usage Example:**
Suppose we want to read a file's attributes in bulk:
```
Path path = ...
BasicFileAttributes attrs = Files.readAttributes(path, BasicFileAttributes.class);
```
Alternatively, suppose we want to read file's POSIX attributes without following symbolic links:
```
PosixFileAttributes attrs =
Files.readAttributes(path, PosixFileAttributes.class, NOFOLLOW_LINKS);
```
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `type` | `Class`: the `Class` of the file attributes required to read
|
| `options` | `LinkOption`: options indicating how symbolic links are handled
|
| Returns ||
|---|---|
| `A` | the file attributes
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, a security manager is installed, its `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file. If this method is invoked to read security sensitive attributes then the security manager may be invoke to check for additional permissions. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if an attributes of the given type are not supported |
### readAttributes
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Map readAttributes (Path path,
String attributes,
LinkOption... options)
```
Reads a set of file attributes as a bulk operation.
The `attributes` parameter identifies the attributes to be read
and takes the form:
> \[*view-name***:** \]*attribute-list*
where square brackets \[...\] delineate an optional component and the character `':'` stands for itself.
*view-name* is the `https://developer.android.com/reference/java/nio/file/attribute/AttributeView#name()` of a `https://developer.android.com/reference/java/nio/file/attribute/FileAttributeView` that identifies a set of file attributes. If not
specified then it defaults to `"basic"`, the name of the file
attribute view that identifies the basic set of file attributes common to
many file systems.
The *attribute-list* component is a comma separated list of
one or more names of attributes to read. If the list contains the value
`"*"` then all attributes are read. Attributes that are not supported
are ignored and will not be present in the returned map. It is
implementation specific if all attributes are read as an atomic operation
with respect to other file system operations.
The following examples demonstrate possible values for the `attributes` parameter:
| Example | Description |
| `"*"` | Read all `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes`. |
| `"size,lastModifiedTime,lastAccessTime"` | Reads the file size, last modified time, and last access time attributes. |
| `"posix:*"` | Read all `https://developer.android.com/reference/java/nio/file/attribute/PosixFileAttributes`. |
| `"posix:permissions,owner,size"` | Reads the POSIX file permissions, owner, and file size. |
|---|---|
[Possible values]
The `options` array may be used to indicate how symbolic links
are handled for the case that the file is a symbolic link. By default,
symbolic links are followed and the file attribute of the final target
of the link is read. If the option `https://developer.android.com/reference/java/nio/file/LinkOption#NOFOLLOW_LINKS` is present then symbolic links are not followed.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `attributes` | `String`: the attributes to read
|
| `options` | `LinkOption`: options indicating how symbolic links are handled
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/Map` | a map of the attributes returned; The map's keys are the attribute names, its values are the attribute values
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if no attributes are specified or an unrecognized attribute is specified |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, its `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method denies read access to the file. If this method is invoked to read security sensitive attributes then the security manager may be invoke to check for additional permissions. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the attribute view is not available |
### readString
Added in [version 36.1](https://developer.android.com/topic/libraries/support-library/revisions)
```
public static String readString (Path path,
Charset cs)
```
Reads all characters from a file into a string, decoding from bytes to characters
using the specified [charset](https://developer.android.com/reference/java/nio/charset/Charset).
The method ensures that the file is closed when all content have been read
or an I/O error, or other runtime exception, is thrown.
This method reads all content including the line separators in the middle
and/or at the end. The resulting string will contain line separators as they
appear in the file.
##### API Note:
- This method is intended for simple cases where it is appropriate and convenient to read the content of a file into a String. It is not intended for reading very large files.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `cs` | `Charset`: the charset to use for decoding
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/String` | a String containing the content read from the file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs reading from the file or a malformed or unmappable byte sequence is read |
| `https://developer.android.com/reference/java/lang/OutOfMemoryError` | if the file is extremely large, for example larger than `2GB` |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file. |
### readString
Added in [version 36.1](https://developer.android.com/topic/libraries/support-library/revisions)
```
public static String readString (Path path)
```
Reads all content from a file into a string, decoding from bytes to characters
using the `https://developer.android.com/reference/java/nio/charset/StandardCharsets#UTF_8` `https://developer.android.com/reference/java/nio/charset/Charset`.
The method ensures that the file is closed when all content have been read
or an I/O error, or other runtime exception, is thrown.
This method is equivalent to:
`readString(path, StandardCharsets.UTF_8) `
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/String` | a String containing the content read from the file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs reading from the file or a malformed or unmappable byte sequence is read |
| `https://developer.android.com/reference/java/lang/OutOfMemoryError` | if the file is extremely large, for example larger than `2GB` |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the file. |
### readSymbolicLink
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path readSymbolicLink (Path link)
```
Reads the target of a symbolic link *(optional operation)*.
If the file system supports [symbolic
links](https://developer.android.com/reference/java/nio/file/package-summary#links) then this method is used to read the target of the link, failing
if the file is not a symbolic link. The target of the link need not exist.
The returned `Path` object will be associated with the same file
system as `link`.
| Parameters ||
|---|---|
| `link` | `Path`: the path to the symbolic link
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | a `Path` object representing the target of the link
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, it checks that `FilePermission` has been granted with the "`readlink`" action to read the link. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the implementation does not support symbolic links |
| `https://developer.android.com/reference/java/nio/file/NotLinkException` | if the target could otherwise not be read because the file is not a symbolic link *(optional specific exception)* |
### setAttribute
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path setAttribute (Path path,
String attribute,
Object value,
LinkOption... options)
```
Sets the value of a file attribute.
The `attribute` parameter identifies the attribute to be set
and takes the form:
> \[*view-name***:** \]*attribute-name*
where square brackets \[...\] delineate an optional component and the character `':'` stands for itself.
*view-name* is the `https://developer.android.com/reference/java/nio/file/attribute/AttributeView#name()` of a `https://developer.android.com/reference/java/nio/file/attribute/FileAttributeView` that identifies a set of file attributes. If not
specified then it defaults to `"basic"`, the name of the file
attribute view that identifies the basic set of file attributes common to
many file systems. *attribute-name* is the name of the attribute
within the set.
The `options` array may be used to indicate how symbolic links
are handled for the case that the file is a symbolic link. By default,
symbolic links are followed and the file attribute of the final target
of the link is set. If the option `https://developer.android.com/reference/java/nio/file/LinkOption#NOFOLLOW_LINKS` is present then symbolic links are not followed.
**Usage Example:**
Suppose we want to set the DOS "hidden" attribute:
```
Path path = ...
Files.setAttribute(path, "dos:hidden", true);
```
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `attribute` | `String`: the attribute to set
|
| `value` | `Object`: the attribute value
|
| `options` | `LinkOption`: options indicating how symbolic links are handled
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the given path
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the attribute value is not of the expected type or is a collection containing elements that are not of the expected type |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the attribute name is not specified, or is not recognized, or the attribute value is of the correct type but has an inappropriate value |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, its `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method denies write access to the file. If this method is invoked to set security sensitive attributes then the security manager may be invoked to check for additional permissions. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the attribute view is not available |
### setLastModifiedTime
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path setLastModifiedTime (Path path,
FileTime time)
```
Updates a file's last modified time attribute. The file time is converted
to the epoch and precision supported by the file system. Converting from
finer to coarser granularities result in precision loss. The behavior of
this method when attempting to set the last modified time when it is not
supported by the file system or is outside the range supported by the
underlying file store is not defined. It may or not fail by throwing an
`IOException`.
**Usage Example:**
Suppose we want to set the last modified time to the current time:
```
Path path = ...
FileTime now = FileTime.fromMillis(System.currentTimeMillis());
Files.setLastModifiedTime(path, now);
```
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `time` | `FileTime`: the new last modified time
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the given path
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, its `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method denies write access to the file. |
**See also:**
- `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributeView#setTimes(java.nio.file.attribute.FileTime,%20java.nio.file.attribute.FileTime,%20java.nio.file.attribute.FileTime)`
### setOwner
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path setOwner (Path path,
UserPrincipal owner)
```
Updates the file owner.
The `path` parameter is associated with a file system that
supports `https://developer.android.com/reference/java/nio/file/attribute/FileOwnerAttributeView`. This file attribute view provides
access to a file attribute that is the owner of the file.
**Usage Example:**
Suppose we want to make "joe" the owner of a file:
```
Path path = ...
UserPrincipalLookupService lookupService =
provider(path).getUserPrincipalLookupService();
UserPrincipal joe = lookupService.lookupPrincipalByName("joe");
Files.setOwner(path, joe);
```
| Parameters ||
|---|---|
| `path` | `Path`: The path to the file
|
| `owner` | `UserPrincipal`: The new file owner
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | The given path
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, it denies `https://developer.android.com/reference/java/lang/RuntimePermission``("accessUserInformation")` or its `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method denies write access to the file. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the associated file system does not support the `FileOwnerAttributeView` |
**See also:**
- `https://developer.android.com/reference/java/nio/file/FileSystem#getUserPrincipalLookupService()`
- `https://developer.android.com/reference/java/nio/file/attribute/UserPrincipalLookupService`
### setPosixFilePermissions
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path setPosixFilePermissions (Path path,
Set perms)
```
Sets a file's POSIX permissions.
The `path` parameter is associated with a `FileSystem`
that supports the `https://developer.android.com/reference/java/nio/file/attribute/PosixFileAttributeView`. This attribute view
provides access to file attributes commonly associated with files on file
systems used by operating systems that implement the Portable Operating
System Interface (POSIX) family of standards.
| Parameters ||
|---|---|
| `path` | `Path`: The path to the file
|
| `perms` | `Set`: The new set of permissions
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | The given path
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/ClassCastException` | if the sets contains elements that are not of type `PosixFilePermission` |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, it denies `https://developer.android.com/reference/java/lang/RuntimePermission``("accessUserInformation")` or its `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method denies write access to the file. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the associated file system does not support the `PosixFileAttributeView` |
### size
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static long size (Path path)
```
Returns the size of a file (in bytes). The size may differ from the
actual size on the file system due to compression, support for sparse
files, or other reasons. The size of files that are not `https://developer.android.com/reference/java/nio/file/Files#isRegularFile(java.nio.file.Path,%20java.nio.file.LinkOption[])` files is implementation specific and
therefore unspecified.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| Returns ||
|---|---|
| `long` | the file size, in bytes
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, its `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method denies read access to the file. |
**See also:**
- `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes#size()`
### walk
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Stream walk (Path start,
int maxDepth,
FileVisitOption... options)
```
Return a `Stream` that is lazily populated with `Path` by walking the file tree rooted at a given starting file. The
file tree is traversed *depth-first* , the elements in the stream
are `https://developer.android.com/reference/java/nio/file/Path` objects that are obtained as if by `https://developer.android.com/reference/java/nio/file/Path#resolve(java.nio.file.Path)` the relative path against `start`.
The `stream` walks the file tree as elements are consumed.
The `Stream` returned is guaranteed to have at least one
element, the starting file itself. For each file visited, the stream
attempts to read its `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes`. If the file is a
directory and can be opened successfully, entries in the directory, and
their *descendants* will follow the directory in the stream as
they are encountered. When all entries have been visited, then the
directory is closed. The file tree walk then continues at the next
*sibling* of the directory.
The stream is *weakly consistent*. It does not freeze the
file tree while iterating, so it may (or may not) reflect updates to
the file tree that occur after returned from this method.
By default, symbolic links are not automatically followed by this
method. If the `options` parameter contains the `https://developer.android.com/reference/java/nio/file/FileVisitOption#FOLLOW_LINKS` option then symbolic links are
followed. When following links, and the attributes of the target cannot
be read, then this method attempts to get the `BasicFileAttributes`
of the link.
If the `options` parameter contains the `https://developer.android.com/reference/java/nio/file/FileVisitOption#FOLLOW_LINKS` option then the stream keeps
track of directories visited so that cycles can be detected. A cycle
arises when there is an entry in a directory that is an ancestor of the
directory. Cycle detection is done by recording the `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes#fileKey()` of directories,
or if file keys are not available, by invoking the `https://developer.android.com/reference/java/nio/file/Files#isSameFile(java.nio.file.Path,%20java.nio.file.Path)` method to test if a directory is the same file as an
ancestor. When a cycle is detected it is treated as an I/O error with
an instance of `https://developer.android.com/reference/java/nio/file/FileSystemLoopException`.
The `maxDepth` parameter is the maximum number of levels of
directories to visit. A value of `0` means that only the starting
file is visited, unless denied by the security manager. A value of
`https://developer.android.com/reference/java/lang/Integer#MAX_VALUE` may be used to indicate that all
levels should be visited.
When a security manager is installed and it denies access to a file
(or directory), then it is ignored and not included in the stream.
The returned stream contains references to one or more open directories.
The directories are closed by closing the stream.
If an `https://developer.android.com/reference/java/io/IOException` is thrown when accessing the directory
after this method has returned, it is wrapped in an `https://developer.android.com/reference/java/io/UncheckedIOException` which will be thrown from the method that caused
the access to take place.
##### API Note:
- This method must be used within a try-with-resources statement or similar control structure to ensure that the stream's open directories are closed promptly after the stream's operations have completed.
| Parameters ||
|---|---|
| `start` | `Path`: the starting file
|
| `maxDepth` | `int`: the maximum number of directory levels to visit
|
| `options` | `FileVisitOption`: options to configure the traversal
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/stream/Stream` | the `https://developer.android.com/reference/java/util/stream/Stream` of `https://developer.android.com/reference/java/nio/file/Path`
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error is thrown when accessing the starting file. |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the `maxDepth` parameter is negative |
| `https://developer.android.com/reference/java/lang/SecurityException` | If the security manager denies access to the starting file. In the case of the default provider, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the directory. |
### walk
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Stream walk (Path start,
FileVisitOption... options)
```
Return a `Stream` that is lazily populated with `Path` by walking the file tree rooted at a given starting file. The
file tree is traversed *depth-first* , the elements in the stream
are `https://developer.android.com/reference/java/nio/file/Path` objects that are obtained as if by `https://developer.android.com/reference/java/nio/file/Path#resolve(java.nio.file.Path)` the relative path against `start`.
This method works as if invoking it were equivalent to evaluating the
expression:
>
> ```
> walk(start, Integer.MAX_VALUE, options)
> ```
In other words, it visits all levels of the file tree.
The returned stream contains references to one or more open directories.
The directories are closed by closing the stream.
##### API Note:
- This method must be used within a try-with-resources statement or similar control structure to ensure that the stream's open directories are closed promptly after the stream's operations have completed.
| Parameters ||
|---|---|
| `start` | `Path`: the starting file
|
| `options` | `FileVisitOption`: options to configure the traversal
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/stream/Stream` | the `https://developer.android.com/reference/java/util/stream/Stream` of `https://developer.android.com/reference/java/nio/file/Path`
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error is thrown when accessing the starting file. |
| `https://developer.android.com/reference/java/lang/SecurityException` | If the security manager denies access to the starting file. In the case of the default provider, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the directory. |
**See also:**
- `https://developer.android.com/reference/java/nio/file/Files#walk(java.nio.file.Path,%20int,%20java.nio.file.FileVisitOption[])`
### walkFileTree
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path walkFileTree (Path start,
FileVisitor visitor)
```
Walks a file tree.
This method works as if invoking it were equivalent to evaluating the
expression:
>
> ```
> walkFileTree(start, EnumSet.noneOf(FileVisitOption.class), Integer.MAX_VALUE, visitor)
> ```
In other words, it does not follow symbolic links, and visits all levels of the file tree.
| Parameters ||
|---|---|
| `start` | `Path`: the starting file
|
| `visitor` | `FileVisitor`: the file visitor to invoke for each file
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the starting file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error is thrown by a visitor method |
| `https://developer.android.com/reference/java/lang/SecurityException` | If the security manager denies access to the starting file. In the case of the default provider, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the directory. |
### walkFileTree
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path walkFileTree (Path start,
Set options,
int maxDepth,
FileVisitor visitor)
```
Walks a file tree.
This method walks a file tree rooted at a given starting file. The
file tree traversal is *depth-first* with the given `https://developer.android.com/reference/java/nio/file/FileVisitor` invoked for each file encountered. File tree traversal
completes when all accessible files in the tree have been visited, or a
visit method returns a result of `https://developer.android.com/reference/java/nio/file/FileVisitResult#TERMINATE`. Where a visit method terminates due an `IOException`,
an uncaught error, or runtime exception, then the traversal is terminated
and the error or exception is propagated to the caller of this method.
For each file encountered this method attempts to read its `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes`. If the file is not a
directory then the `https://developer.android.com/reference/java/nio/file/FileVisitor#visitFile(T,%20java.nio.file.attribute.BasicFileAttributes)` method is
invoked with the file attributes. If the file attributes cannot be read,
due to an I/O exception, then the `https://developer.android.com/reference/java/nio/file/FileVisitor#visitFileFailed(T,%20java.io.IOException)` method is invoked with the I/O exception.
Where the file is a directory, and the directory could not be opened,
then the `visitFileFailed` method is invoked with the I/O exception,
after which, the file tree walk continues, by default, at the next
*sibling* of the directory.
Where the directory is opened successfully, then the entries in the
directory, and their *descendants* are visited. When all entries
have been visited, or an I/O error occurs during iteration of the
directory, then the directory is closed and the visitor's `https://developer.android.com/reference/java/nio/file/FileVisitor#postVisitDirectory(T,%20java.io.IOException)` method is invoked.
The file tree walk then continues, by default, at the next *sibling*
of the directory.
By default, symbolic links are not automatically followed by this
method. If the `options` parameter contains the `https://developer.android.com/reference/java/nio/file/FileVisitOption#FOLLOW_LINKS` option then symbolic links are
followed. When following links, and the attributes of the target cannot
be read, then this method attempts to get the `BasicFileAttributes`
of the link. If they can be read then the `visitFile` method is
invoked with the attributes of the link (otherwise the `visitFileFailed`
method is invoked as specified above).
If the `options` parameter contains the `https://developer.android.com/reference/java/nio/file/FileVisitOption#FOLLOW_LINKS` option then this method keeps
track of directories visited so that cycles can be detected. A cycle
arises when there is an entry in a directory that is an ancestor of the
directory. Cycle detection is done by recording the `https://developer.android.com/reference/java/nio/file/attribute/BasicFileAttributes#fileKey()` of directories,
or if file keys are not available, by invoking the `https://developer.android.com/reference/java/nio/file/Files#isSameFile(java.nio.file.Path,%20java.nio.file.Path)` method to test if a directory is the same file as an
ancestor. When a cycle is detected it is treated as an I/O error, and the
`https://developer.android.com/reference/java/nio/file/FileVisitor#visitFileFailed(T,%20java.io.IOException)` method is invoked with
an instance of `https://developer.android.com/reference/java/nio/file/FileSystemLoopException`.
The `maxDepth` parameter is the maximum number of levels of
directories to visit. A value of `0` means that only the starting
file is visited, unless denied by the security manager. A value of
`https://developer.android.com/reference/java/lang/Integer#MAX_VALUE` may be used to indicate that all
levels should be visited. The `visitFile` method is invoked for all
files, including directories, encountered at `maxDepth`, unless the
basic file attributes cannot be read, in which case the `visitFileFailed` method is invoked.
If a visitor returns a result of `null` then `NullPointerException` is thrown.
When a security manager is installed and it denies access to a file
(or directory), then it is ignored and the visitor is not invoked for
that file (or directory).
| Parameters ||
|---|---|
| `start` | `Path`: the starting file
|
| `options` | `Set`: options to configure the traversal
|
| `maxDepth` | `int`: the maximum number of directory levels to visit
|
| `visitor` | `FileVisitor`: the file visitor to invoke for each file
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the starting file
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error is thrown by a visitor method |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if the `maxDepth` parameter is negative |
| `https://developer.android.com/reference/java/lang/SecurityException` | If the security manager denies access to the starting file. In the case of the default provider, the `https://developer.android.com/reference/java/lang/SecurityManager#checkRead(java.lang.String)` method is invoked to check read access to the directory. |
### write
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path write (Path path,
Iterable lines,
Charset cs,
OpenOption... options)
```
Write lines of text to a file. Each line is a char sequence and is
written to the file in sequence with each line terminated by the
platform's line separator, as defined by the system property `line.separator`. Characters are encoded into bytes using the specified
charset.
The `options` parameter specifies how the file is created
or opened. If no options are present then this method works as if the
`https://developer.android.com/reference/java/nio/file/StandardOpenOption#CREATE`, `https://developer.android.com/reference/java/nio/file/StandardOpenOption#TRUNCATE_EXISTING`, and `https://developer.android.com/reference/java/nio/file/StandardOpenOption#WRITE` options are present. In other words, it
opens the file for writing, creating the file if it doesn't exist, or
initially truncating an existing `https://developer.android.com/reference/java/nio/file/Files#isRegularFile(java.nio.file.Path,%20java.nio.file.LinkOption[])` to
a size of `0`. The method ensures that the file is closed when all
lines have been written (or an I/O error or other runtime exception is
thrown). If an I/O error occurs then it may do so after the file has
been created or truncated, or after some bytes have been written to the
file.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `lines` | `Iterable`: an object to iterate over the char sequences
|
| `cs` | `Charset`: the charset to use for encoding
|
| `options` | `OpenOption`: options specifying how the file is opened
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the path
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs writing to or creating the file, or the text cannot be encoded using the specified charset |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if `options` contains an invalid combination of options |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the file. The `https://developer.android.com/reference/java/lang/SecurityManager#checkDelete(java.lang.String)` method is invoked to check delete access if the file is opened with the `DELETE_ON_CLOSE` option. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if an unsupported option is specified |
### write
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path write (Path path,
byte[] bytes,
OpenOption... options)
```
Writes bytes to a file. The `options` parameter specifies how
the file is created or opened. If no options are present then this method
works as if the `https://developer.android.com/reference/java/nio/file/StandardOpenOption#CREATE`, `https://developer.android.com/reference/java/nio/file/StandardOpenOption#TRUNCATE_EXISTING`, and `https://developer.android.com/reference/java/nio/file/StandardOpenOption#WRITE` options are present. In other words, it
opens the file for writing, creating the file if it doesn't exist, or
initially truncating an existing `https://developer.android.com/reference/java/nio/file/Files#isRegularFile(java.nio.file.Path,%20java.nio.file.LinkOption[])` to
a size of `0`. All bytes in the byte array are written to the file.
The method ensures that the file is closed when all bytes have been
written (or an I/O error or other runtime exception is thrown). If an I/O
error occurs then it may do so after the file has been created or
truncated, or after some bytes have been written to the file.
**Usage example**: By default the method creates a new file or
overwrites an existing file. Suppose you instead want to append bytes
to an existing file:
```
Path path = ...
byte[] bytes = ...
Files.write(path, bytes, StandardOpenOption.APPEND);
```
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `bytes` | `byte`: the byte array with the bytes to write
|
| `options` | `OpenOption`: options specifying how the file is opened
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the path
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs writing to or creating the file |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if `options` contains an invalid combination of options |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the file. The `https://developer.android.com/reference/java/lang/SecurityManager#checkDelete(java.lang.String)` method is invoked to check delete access if the file is opened with the `DELETE_ON_CLOSE` option. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if an unsupported option is specified |
### write
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public static Path write (Path path,
Iterable lines,
OpenOption... options)
```
Write lines of text to a file. Characters are encoded into bytes using
the `https://developer.android.com/reference/java/nio/charset/StandardCharsets#UTF_8` `https://developer.android.com/reference/java/nio/charset/Charset`.
This method works as if invoking it were equivalent to evaluating the
expression:
Files.write(path, lines, StandardCharsets.UTF_8, options);
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `lines` | `Iterable`: an object to iterate over the char sequences
|
| `options` | `OpenOption`: options specifying how the file is opened
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the path
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs writing to or creating the file, or the text cannot be encoded as `UTF-8` |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if `options` contains an invalid combination of options |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the file. The `https://developer.android.com/reference/java/lang/SecurityManager#checkDelete(java.lang.String)` method is invoked to check delete access if the file is opened with the `DELETE_ON_CLOSE` option. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if an unsupported option is specified |
### writeString
Added in [version 36.1](https://developer.android.com/topic/libraries/support-library/revisions)
```
public static Path writeString (Path path,
CharSequence csq,
OpenOption... options)
```
Write a [CharSequence](https://developer.android.com/reference/java/lang/CharSequence) to a file.
Characters are encoded into bytes using the
`https://developer.android.com/reference/java/nio/charset/StandardCharsets#UTF_8` `https://developer.android.com/reference/java/nio/charset/Charset`.
This method is equivalent to:
`writeString(path, test, StandardCharsets.UTF_8, options) `
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `csq` | `CharSequence`: the CharSequence to be written
|
| `options` | `OpenOption`: options specifying how the file is opened
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the path
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs writing to or creating the file, or the text cannot be encoded using the specified charset |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if `options` contains an invalid combination of options |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the file. The `https://developer.android.com/reference/java/lang/SecurityManager#checkDelete(java.lang.String)` method is invoked to check delete access if the file is opened with the `DELETE_ON_CLOSE` option. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if an unsupported option is specified |
### writeString
Added in [version 36.1](https://developer.android.com/topic/libraries/support-library/revisions)
```
public static Path writeString (Path path,
CharSequence csq,
Charset cs,
OpenOption... options)
```
Write a [CharSequence](https://developer.android.com/reference/java/lang/CharSequence) to a file.
Characters are encoded into bytes using the specified
[charset](https://developer.android.com/reference/java/nio/charset/Charset).
All characters are written as they are, including the line separators in
the char sequence. No extra characters are added.
The `options` parameter specifies how the file is created
or opened. If no options are present then this method works as if the
`https://developer.android.com/reference/java/nio/file/StandardOpenOption#CREATE`, `https://developer.android.com/reference/java/nio/file/StandardOpenOption#TRUNCATE_EXISTING`, and `https://developer.android.com/reference/java/nio/file/StandardOpenOption#WRITE` options are present. In other words, it
opens the file for writing, creating the file if it doesn't exist, or
initially truncating an existing `https://developer.android.com/reference/java/nio/file/Files#isRegularFile(java.nio.file.Path,%20java.nio.file.LinkOption[])` to
a size of `0`.
| Parameters ||
|---|---|
| `path` | `Path`: the path to the file
|
| `csq` | `CharSequence`: the CharSequence to be written
|
| `cs` | `Charset`: the charset to use for encoding
|
| `options` | `OpenOption`: options specifying how the file is opened
|
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/nio/file/Path` | the path
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/io/IOException` | if an I/O error occurs writing to or creating the file, or the text cannot be encoded using the specified charset |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` | if `options` contains an invalid combination of options |
| `https://developer.android.com/reference/java/lang/SecurityException` | In the case of the default provider, and a security manager is installed, the `https://developer.android.com/reference/java/lang/SecurityManager#checkWrite(java.lang.String)` method is invoked to check write access to the file. The `https://developer.android.com/reference/java/lang/SecurityManager#checkDelete(java.lang.String)` method is invoked to check delete access if the file is opened with the `DELETE_ON_CLOSE` option. |
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if an unsupported option is specified |