Process

Class Overview

Represents an external process. Enables writing to, reading from, destroying, and waiting for the external process, as well as querying its exit value. Use ProcessBuilder to create processes.

The child process writes its output to two streams, out and err. These streams should be read by the parent process using getInputStream() and getErrorStream() respectively. If these streams are not read, the target process may block while it awaits buffer space. It isn't sufficient to read the streams in sequence; to avoid blocking each of the two streams must have its own reader thread. If you are not interested in differentiating the out and err streams, use redirectErrorStream(true) to merge the two streams. This simplifies your reading code and makes it easier to avoid blocking the target process.

Running processes hold resources. When a process is no longer used, the process should be closed by calling destroy(). This will kill the process and release the resources that it holds.

For example, to run /system/bin/ping to ping android.com:

   Process process = new ProcessBuilder()
       .command("/system/bin/ping", "android.com")
       .redirectErrorStream(true)
       .start();
   try {
     InputStream in = process.getInputStream();
     OutputStream out = process.getOutputStream();
     readStream(in);
    finally {
     process.destroy();
   }
 }

Summary

[Expand] Inherited Methods

From class java.lang.Object Object clone() Creates and returns a copy of this Object. boolean equals(Object o) Compares this instance with the specified object and indicates if they are equal. void finalize() Invoked when the garbage collector has detected that this instance is no longer reachable. final Class<?> getClass() Returns the unique instance of Class that represents this object's class. int hashCode() Returns an integer hash code for this object. final void notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up. final void notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up. String toString() Returns a string containing a concise, human-readable description of this object. final void wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object. final void wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires. final void wait(long millis) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.