| java.lang.Object | |
| ↳ | java.lang.Process |
Class Overview
The start() and
Runtime.exec
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. 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
through three streams
(getOutputStream(),
getInputStream(),
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, and even deadlock.
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.
See Also
Summary
| Public Constructors | |||||||||||
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| Public Methods | |||||||||||
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Kills the subprocess.
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Returns the exit value for the subprocess.
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Returns the input stream connected to the error output stream of
the subprocess.
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Returns the input stream connected to the normal output of the
subprocess.
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Returns the output stream connected to the normal input of the
subprocess.
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Causes the current thread to wait, if necessary, until the
process represented by this
Process object has
terminated. | |||||||||||
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[Expand]
Inherited Methods | |||||||||||
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From class
java.lang.Object
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Public Constructors
public Process ()
Public Methods
public abstract void destroy ()
Kills the subprocess. The subprocess represented by this
Process object is forcibly terminated.
public abstract int exitValue ()
Returns the exit value for the subprocess.
Returns
- the exit value of the subprocess represented by this
Processobject. By convention, the value0indicates normal termination.
Throws
| IllegalThreadStateException | if the subprocess represented
by this Process object has not yet terminated
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public abstract InputStream getErrorStream ()
Returns the input stream connected to the error output stream of
the subprocess. The stream obtains data piped from the error
output stream of the process represented by this Process
object.
Implementation note: It is a good idea for the returned input stream to be buffered.
Returns
- the input stream connected to the error output stream of the subprocess
See Also
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 stream of the process represented by this Process object.
Implementation note: It is a good idea for the returned input stream to be buffered.
Returns
- the input stream connected to the normal output of the subprocess
See Also
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 stream of the process represented by this Process
object.
Implementation note: It is a good idea for the returned output stream to be buffered.
Returns
- the output stream connected to the normal input of the subprocess
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
- the exit value of the subprocess represented by this
Processobject. By convention, the value0indicates normal termination.
Throws
| InterruptedException | if the current thread is
interrupted by another
thread while it is waiting, then the wait is ended and
an InterruptedException is thrown.
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