CODEWITHSUNDEEP
javaprocess
Thomas Johnson
Thomas Johnson

Reputation: 1

Shutdown spawned java child process gracefully

I use ProcessBuilder to spawn a child process for executing writing some data to file system. And a problem occurs because the parent process may crash/ killed unexpectedly, the child process just hangs even I use e.g. jps checking if its parent process dies then exits. What is the right way for a spawned child process to detects if its parent process is dead and then exit?

Also, After searching on the internet, most solution use Runtime.addShutdownHook(), but this is not provided in ProcessBuilder. Does it have equivalent one?

Upvotes: 0

Views: 2699

Answers (2)

Luca
Luca

Reputation: 1

In a similar situation I implemented a heartbeat mechanism where the parent process had to regularly send heartbeats. If that did not happen the child process would shut itself down.

Upvotes: 0

JiP
JiP

Reputation: 3258

You did a good search around the problem. So you may want to use the returned reference to the Process instance and the Runtime.addShutdownHook(Thread) method you mentioned. This is the last step that I believe you need to take:


List commands = new ArrayList();
commands.add("xeyes"); // launch this command
ProcessBuilder pb = new ProcessBuilder(commands);
final Process p = pb.start();
Runtime.getRuntime().addShutdownHook(new Thread() {
  @Override
  public void run() {
    p.destroy();
  }
});

Thread.sleep(2000); // sleep for some time

Upvotes: 3

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