Gracefully exit from a Linux kill

Question

Is there a way to gracefully exit from a Linux kill command?
Given the following code:
  public static void main(String[] args) throws IOException
    boolean bExit = false;
    while (!bExit)
      try
        Thread.sleep(1000L);
      catch (InterruptedException ex)
        bExit = true;
    System.out.println("Program exiting gracefully.");
  }Is there a way for the Linux kill command to make the message "Program exiting gracefully." appear?

Answer 1

Certainly not for kill -9.
But you can look at Runtime.addShutdownHook().The problem I have with Runtime.addShutdownHook() is (from the API Javadoc):
"Shutdown hooks should also finish their work quickly. When a program invokes exit the expectation is that the virtual machine will promptly shut down and exit. When the virtual machine is terminated due to user logoff or system shutdown the underlying operating system may only allow a fixed amount of time in which to shut down and exit. It is therefore inadvisable to attempt any user interaction or to perform a long-running computation in a shutdown hook."
I just was wondering if there was a built-in hook for the kill command like the hook for "kill -3" that calls the Thread.interrupt() method on the main thread of execution.
My actual code is more like:
  public static void main(String[] args) throws IOException
    boolean bExit = false;
    SubThreadManager1.init();
    SubThreadManager2.init();
    while (!bExit)
      try
        Thread.sleep(1000);
      catch (InterruptedException ex)
        bExit = true;
    // After these shutdown methods are called it could take up
    // to 30 seconds before they reach the stopped state.
    SubThreadManager1.shutdown();
    SubThreadManager2.shutdown();
    while (!SubThreadManager1.isStopped() || !SubThreadManager2.isStopped())
      try
        Thread.sleep(500L);
      catch (InterruptedException ex)
    System.out.println("Program exiting gracefully.");
  }I was just simplifiying the test case to get the point across.