How do I find the process ID (pid) of a process started in java? [duplicate]

Question

If I get a process object in Java through Runtime.getRuntime().exec(...), or ProcessBuilder.start(), I can wait for it through Process.waitFor(), which is like Thread.join(), or I could kill it with Process.destroy(), which is like the deprecated Thread.stop().

BUT: How do I find the pid of the Process Object? I don't see a method for doing that in The Official Documentation. Can I do this in Java? If so, how?

Answer 1

This guy calls out to bash to get the PID. I'm not sure if there is an java solution to the problem.

/**
 * Gets a string representing the pid of this program - Java VM
 */
public static String getPid() throws IOException,InterruptedException {

  Vector<String> commands=new Vector<String>();
  commands.add("/bin/bash");
  commands.add("-c");
  commands.add("echo $PPID");
  ProcessBuilder pb=new ProcessBuilder(commands);

  Process pr=pb.start();
  pr.waitFor();
  if (pr.exitValue()==0) {
    BufferedReader outReader=new BufferedReader(new InputStreamReader(pr.getInputStream()));
    return outReader.readLine().trim();
  } else {
    System.out.println("Error while getting PID");
    return "";
  }
}

Source: http://www.coderanch.com/t/109334/Linux-UNIX/UNIX-process-ID-java-program

Answer 2

Similar to the other tools mentioned, there is the jps command line tool that comes with the Java runtime. It spits out the PIDs of all running JVMs. The benefit is the output one needs to parse is confined to only the JVM processes.