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SecureClassLoader

public class SecureClassLoader
extends ClassLoader

java.lang.Object
   ↳ java.lang.ClassLoader
     ↳ java.security.SecureClassLoader


This class extends ClassLoader with additional support for defining classes with an associated code source and permissions which are retrieved by the system policy by default.

Summary

Protected constructors

SecureClassLoader(ClassLoader parent)

Creates a new SecureClassLoader using the specified parent class loader for delegation.

SecureClassLoader()

Creates a new SecureClassLoader using the default parent class loader for delegation.

Protected methods

final Class<?> defineClass(String name, byte[] b, int off, int len, CodeSource cs)

Converts an array of bytes into an instance of class Class, with an optional CodeSource.

final Class<?> defineClass(String name, ByteBuffer b, CodeSource cs)

Converts a ByteBuffer into an instance of class Class, with an optional CodeSource.

PermissionCollection getPermissions(CodeSource codesource)

Returns the permissions for the given CodeSource object.

Inherited methods

Protected constructors

SecureClassLoader

added in API level 1
protected SecureClassLoader (ClassLoader parent)

Creates a new SecureClassLoader using the specified parent class loader for delegation.

If there is a security manager, this method first calls the security manager's checkCreateClassLoader method to ensure creation of a class loader is allowed.

Parameters
parent ClassLoader: the parent ClassLoader

Throws
SecurityException if a security manager exists and its checkCreateClassLoader method doesn't allow creation of a class loader.

SecureClassLoader

added in API level 1
protected SecureClassLoader ()

Creates a new SecureClassLoader using the default parent class loader for delegation.

If there is a security manager, this method first calls the security manager's checkCreateClassLoader method to ensure creation of a class loader is allowed.

Throws
SecurityException if a security manager exists and its checkCreateClassLoader method doesn't allow creation of a class loader.

Protected methods

defineClass

added in API level 1
protected final Class<?> defineClass (String name, 
                byte[] b, 
                int off, 
                int len, 
                CodeSource cs)

Converts an array of bytes into an instance of class Class, with an optional CodeSource. Before the class can be used it must be resolved.

If a non-null CodeSource is supplied a ProtectionDomain is constructed and associated with the class being defined.

Parameters
name String: the expected name of the class, or null if not known, using '.' and not '/' as the separator and without a trailing ".class" suffix.

b byte: the bytes that make up the class data. The bytes in positions off through off+len-1 should have the format of a valid class file as defined by The Java™ Virtual Machine Specification.

off int: the start offset in b of the class data

len int: the length of the class data

cs CodeSource: the associated CodeSource, or null if none

Returns
Class<?> the Class object created from the data, and optional CodeSource.

Throws
ClassFormatError if the data did not contain a valid class
IndexOutOfBoundsException if either off or len is negative, or if off+len is greater than b.length.
SecurityException if an attempt is made to add this class to a package that contains classes that were signed by a different set of certificates than this class, or if the class name begins with "java.".

defineClass

added in API level 1
protected final Class<?> defineClass (String name, 
                ByteBuffer b, 
                CodeSource cs)

Converts a ByteBuffer into an instance of class Class, with an optional CodeSource. Before the class can be used it must be resolved.

If a non-null CodeSource is supplied a ProtectionDomain is constructed and associated with the class being defined.

Parameters
name String: the expected name of the class, or null if not known, using '.' and not '/' as the separator and without a trailing ".class" suffix.

b ByteBuffer: the bytes that make up the class data. The bytes from positions b.position() through b.position() + b.limit() -1 should have the format of a valid class file as defined by The Java™ Virtual Machine Specification.

cs CodeSource: the associated CodeSource, or null if none

Returns
Class<?> the Class object created from the data, and optional CodeSource.

Throws
ClassFormatError if the data did not contain a valid class
SecurityException if an attempt is made to add this class to a package that contains classes that were signed by a different set of certificates than this class, or if the class name begins with "java.".

getPermissions

added in API level 1
protected PermissionCollection getPermissions (CodeSource codesource)

Returns the permissions for the given CodeSource object.

This method is invoked by the defineClass method which takes a CodeSource as an argument when it is constructing the ProtectionDomain for the class being defined.

Parameters
codesource CodeSource: the codesource.

Returns
PermissionCollection the permissions granted to the codesource.