Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Ctors](https://developer.android.com/reference/java/lang/Process#pubctors) \| [Methods](https://developer.android.com/reference/java/lang/Process#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/java/lang/Process#inhmethods)
# Process
`
public
abstract
class
Process
`
`
extends https://developer.android.com/reference/java/lang/Object
`
`
`
|---|---|
| [java.lang.Object](https://developer.android.com/reference/java/lang/Object) ||
| ↳ | java.lang.Process |
*** ** * ** ***
The `https://developer.android.com/reference/java/lang/ProcessBuilder#start()` and
`https://developer.android.com/reference/java/lang/Runtime#exec(java.lang.String[],%20java.lang.String[],%20java.io.File)`
methods create a native process and return an instance of a
subclass of `Process` that can be used to control the process
and obtain information about it. The class `Process`
provides methods for performing input from the process, performing
output to the process, waiting for the process to complete,
checking the exit status of the process, and destroying (killing)
the process.
The methods that create processes may not work well for special
processes on certain native platforms, such as native windowing
processes, daemon processes, Win16/DOS processes on Microsoft
Windows, or shell scripts.
By default, the created subprocess does not have its own terminal
or console. All its standard I/O (i.e. stdin, stdout, stderr)
operations will be redirected to the parent process, where they can
be accessed via the streams obtained using the methods
`https://developer.android.com/reference/java/lang/Process#getOutputStream()`,
`https://developer.android.com/reference/java/lang/Process#getInputStream()`, and
`https://developer.android.com/reference/java/lang/Process#getErrorStream()`.
The parent process uses these streams to feed input to and get output
from the subprocess. Because some native platforms only provide
limited buffer size for standard input and output streams, failure
to promptly write the input stream or read the output stream of
the subprocess may cause the subprocess to block, or even deadlock.
Where desired, [subprocess I/O can also be redirected](https://developer.android.com/reference/java/lang/ProcessBuilder#redirect-input)
using methods of the `https://developer.android.com/reference/java/lang/ProcessBuilder` class.
The subprocess is not killed when there are no more references to
the `Process` object, but rather the subprocess
continues executing asynchronously.
There is no requirement that a process represented by a `Process` object execute asynchronously or concurrently with respect
to the Java process that owns the `Process` object.
As of 1.5, `https://developer.android.com/reference/java/lang/ProcessBuilder#start()` is the preferred way
to create a `Process`.
## Summary
| ### Public constructors ||
|---|---|
| ` https://developer.android.com/reference/java/lang/Process#Process()() ` |
| ### Public methods ||
|---|---|
| ` abstract void` | ` https://developer.android.com/reference/java/lang/Process#destroy()() ` Kills the subprocess. |
| ` https://developer.android.com/reference/java/lang/Process` | ` https://developer.android.com/reference/java/lang/Process#destroyForcibly()() ` Kills the subprocess. |
| ` abstract int` | ` https://developer.android.com/reference/java/lang/Process#exitValue()() ` Returns the exit value for the subprocess. |
| ` abstract https://developer.android.com/reference/java/io/InputStream` | ` https://developer.android.com/reference/java/lang/Process#getErrorStream()() ` Returns the input stream connected to the error output of the subprocess. |
| ` abstract https://developer.android.com/reference/java/io/InputStream` | ` https://developer.android.com/reference/java/lang/Process#getInputStream()() ` Returns the input stream connected to the normal output of the subprocess. |
| ` abstract https://developer.android.com/reference/java/io/OutputStream` | ` https://developer.android.com/reference/java/lang/Process#getOutputStream()() ` Returns the output stream connected to the normal input of the subprocess. |
| ` boolean` | ` https://developer.android.com/reference/java/lang/Process#isAlive()() ` Tests whether the subprocess represented by this `Process` is alive. |
| ` long` | ` https://developer.android.com/reference/java/lang/Process#pid()() ` Returns the native process ID of the process. |
| ` abstract int` | ` https://developer.android.com/reference/java/lang/Process#waitFor()() ` Causes the current thread to wait, if necessary, until the process represented by this `Process` object has terminated. |
| ` boolean` | ` https://developer.android.com/reference/java/lang/Process#waitFor(long,%20java.util.concurrent.TimeUnit)(long timeout, https://developer.android.com/reference/java/util/concurrent/TimeUnit unit) ` Causes the current thread to wait, if necessary, until the subprocess represented by this `Process` object has terminated, or the specified waiting time elapses. |
### 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 constructors
### Process
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public Process ()
```
## Public methods
### destroy
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public abstract void destroy ()
```
Kills the subprocess. Whether the subprocess represented by this
`Process` object is forcibly terminated or not is
implementation dependent.
### destroyForcibly
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public Process destroyForcibly ()
```
Kills the subprocess. The subprocess represented by this
`Process` object is forcibly terminated.
The default implementation of this method invokes `https://developer.android.com/reference/java/lang/Process#destroy()`
and so may not forcibly terminate the process. Concrete implementations
of this class are strongly encouraged to override this method with a
compliant implementation. Invoking this method on `Process`
objects returned by `https://developer.android.com/reference/java/lang/ProcessBuilder#start()` and
`https://developer.android.com/reference/java/lang/Runtime#exec(java.lang.String)` will forcibly terminate the process.
Note: The subprocess may not terminate immediately.
i.e. `isAlive()` may return true for a brief period
after `destroyForcibly()` is called. This method
may be chained to `waitFor()` if needed.
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/lang/Process` | the `Process` object representing the subprocess to be forcibly destroyed.
|
### exitValue
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public abstract int exitValue ()
```
Returns the exit value for the subprocess.
| Returns ||
|---|---|
| `int` | the exit value of the subprocess represented by this `Process` object. By convention, the value `0` indicates normal termination.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/IllegalThreadStateException` | if the subprocess represented by this `Process` object has not yet terminated |
### getErrorStream
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public abstract InputStream getErrorStream ()
```
Returns the input stream connected to the error output of the
subprocess. The stream obtains data piped from the error output
of the process represented by this `Process` object.
If the standard error of the subprocess has been redirected using
`https://developer.android.com/reference/java/lang/ProcessBuilder#redirectError(java.lang.ProcessBuilder.Redirect)` or
`https://developer.android.com/reference/java/lang/ProcessBuilder#redirectErrorStream(boolean)`
then this method will return a
[null input stream](https://developer.android.com/reference/java/lang/ProcessBuilder#redirect-output).
Implementation note: It is a good idea for the returned
input stream to be buffered.
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/io/InputStream` | the input stream connected to the error output of the subprocess
|
### getInputStream
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public abstract InputStream getInputStream ()
```
Returns the input stream connected to the normal output of the
subprocess. The stream obtains data piped from the standard
output of the process represented by this `Process` object.
If the standard output of the subprocess has been redirected using
`https://developer.android.com/reference/java/lang/ProcessBuilder#redirectOutput(java.lang.ProcessBuilder.Redirect)`
then this method will return a
[null input stream](https://developer.android.com/reference/java/lang/ProcessBuilder#redirect-output).
Otherwise, if the standard error of the subprocess has been
redirected using
`https://developer.android.com/reference/java/lang/ProcessBuilder#redirectErrorStream(boolean)`
then the input stream returned by this method will receive the
merged standard output and the standard error of the subprocess.
Implementation note: It is a good idea for the returned
input stream to be buffered.
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/io/InputStream` | the input stream connected to the normal output of the subprocess
|
### getOutputStream
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public abstract OutputStream getOutputStream ()
```
Returns the output stream connected to the normal input of the
subprocess. Output to the stream is piped into the standard
input of the process represented by this `Process` object.
If the standard input of the subprocess has been redirected using
`https://developer.android.com/reference/java/lang/ProcessBuilder#redirectInput(java.lang.ProcessBuilder.Redirect)`
then this method will return a
[null output stream](https://developer.android.com/reference/java/lang/ProcessBuilder#redirect-input).
Implementation note: It is a good idea for the returned
output stream to be buffered.
| Returns ||
|---|---|
| `https://developer.android.com/reference/java/io/OutputStream` | the output stream connected to the normal input of the subprocess
|
### isAlive
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public boolean isAlive ()
```
Tests whether the subprocess represented by this `Process` is
alive.
| Returns ||
|---|---|
| `boolean` | `true` if the subprocess represented by this `Process` object has not yet terminated.
|
### pid
Added in [version 37.2](https://developer.android.com/topic/libraries/support-library/revisions)
```
public long pid ()
```
Returns the native process ID of the process.
The native process ID is an identification number that the operating
system assigns to the process.
##### Implementation Requirements:
- The implementation of this method returns the process id as: `https://developer.android.com/`.
| Returns ||
|---|---|
| `long` | the native process id of the process
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException` | if the Process implementation does not support this operation |
### waitFor
Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public abstract int waitFor ()
```
Causes the current thread to wait, if necessary, until the
process represented by this `Process` object has
terminated. This method returns immediately if the subprocess
has already terminated. If the subprocess has not yet
terminated, the calling thread will be blocked until the
subprocess exits.
| Returns ||
|---|---|
| `int` | the exit value of the subprocess represented by this `Process` object. By convention, the value `0` indicates normal termination.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/InterruptedException` | if the current thread is [interrupted](https://developer.android.com/reference/java/lang/Thread#interrupt()) by another thread while it is waiting, then the wait is ended and an `https://developer.android.com/reference/java/lang/InterruptedException` is thrown. |
### waitFor
Added in [API level 26](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)
```
public boolean waitFor (long timeout,
TimeUnit unit)
```
Causes the current thread to wait, if necessary, until the
subprocess represented by this `Process` object has
terminated, or the specified waiting time elapses.
If the subprocess has already terminated then this method returns
immediately with the value `true`. If the process has not
terminated and the timeout value is less than, or equal to, zero, then
this method returns immediately with the value `false`.
The default implementation of this methods polls the `exitValue`
to check if the process has terminated. Concrete implementations of this
class are strongly encouraged to override this method with a more
efficient implementation.
| Parameters ||
|---|---|
| `timeout` | `long`: the maximum time to wait
|
| `unit` | `TimeUnit`: the time unit of the `timeout` argument
|
| Returns ||
|---|---|
| `boolean` | `true` if the subprocess has exited and `false` if the waiting time elapsed before the subprocess has exited.
|
| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/InterruptedException` | if the current thread is interrupted while waiting. |
| `https://developer.android.com/reference/java/lang/NullPointerException` | if unit is null |