Thread-launched running processes won't destroy (Java)

java multithreading process destroy
Bastien picture Bastien · Aug 7, 2013 · Viewed 18.3k times · Source

Starting multiple threads and having each exec() then destroy() a running java process result in some of the process not being destroyed and still running after program exit. Here is some code that reproduce the issue. I noticed the more threads you start, the more processes stay alive. And the more sleep before destroy(), the less processes stay alive. (I used InfiniteLoop as an example. Any running process will do the trick.)

EDIT : Bug has been reported to Oracle, waiting for an answer. Feel free to share any knowledge/experiments on the subject.

for(int i = 0; i < 100; i++)
{
  new Thread(new Runnable()
  {
    public void run()
    {
      try
      {
        Process p = Runtime.getRuntime().exec(new String[]{"java", "InfiniteLoop"});
        Thread.sleep(1);
        p.destroy();
      }catch(IOException | InterruptedException e){e.printStackTrace();}                    
    }
  }).start();
}

Answer

Abhishek picture Abhishek · Aug 15, 2013

Use a p.waitFor(); before p.destroy(); ,

this will ensure the completion of the previous process. I think you p.destroy command gets invoked sooner than the exec() command performs the action. Therefore it becomes useless.

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