Class: java.lang.Process
- public abstract class Process
The ProcessBuilder.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 io (i.e. stdin, stdout, stderr) operations will be redirected to the parent process through three streams (Process.getOutputStream(), Process.getInputStream(), 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, 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.
Methods
-
Processtop
public Process() -
destroytop
public abstract void destroy()Kills the subprocess. The subprocess represented by thisProcessobject is forcibly terminated. -
exitValuetop
public abstract int exitValue()Returns the exit value for the subprocess. -
getErrorStreamtop
public abstract InputStream getErrorStream()Gets the error stream of the subprocess. The stream obtains data piped from the error output stream of the process represented by thisProcessobject.Implementation note: It is a good idea for the input stream to be buffered.
-
getInputStreamtop
public abstract InputStream getInputStream()Gets the input stream of the subprocess. The stream obtains data piped from the standard output stream of the process represented by thisProcessobject.Implementation note: It is a good idea for the input stream to be buffered.
-
getOutputStreamtop
public abstract OutputStream getOutputStream()Gets the output stream of the subprocess. Output to the stream is piped into the standard input stream of the process represented by thisProcessobject.Implementation note: It is a good idea for the output stream to be buffered.
-
waitFortop
public abstract int waitFor() throws InterruptedExceptioncauses the current thread to wait, if necessary, until the process represented by thisProcessobject 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.