[IO-535] Thread bug in FileAlterationMonitor#stop(int)

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.5
• Fix Version/s: 2.7
• Component/s: Utilities
• Labels: easyfix patch performance

Environment

Components managed by a DI Framework

• Flags: Patch
• External issue URL: https://github.com/apache/commons-io/pull/36
• Assignee: Pascal Schumacher
• Reporter: Anthony RAYMOND
• Created: 01/May/17 23:48
• Updated: 29/Apr/18 09:22
• Resolved: 29/Apr/18 09:22

Description

The thread in FileAlterationMonitor wasn't stopped by the `stop(int)` method, which forbid application to shutdown until all `Thread` are exited (if FileAlterationMonitor is part of a DI managed component).

This behavior conflict with the method javadoc `@param stopInterval the amount of time in milliseconds to wait for the thread to finish.`

Simple example to understand

Bad behavior

    Thread t = new Thread(() -> {
        try {
            Thread.sleep(500000);
        } catch (final InterruptedException e) {
        }
    });
    t.start();
    t.join(50);
   // Ok, we reach this point until 500000ms are elapsed, but the thread is still alive.
   //   because Thread#join(int) does not kill the thread. And the thread remains alive.

Good behavior

    Thread t = new Thread(() -> {
        try {
            Thread.sleep(500000);
        } catch (final InterruptedException e) {
        }
    });
    t.start();
    t.join(50);
    t.interupt();
   // Thread is exited

In this case, we waited the given time BEFORE exiting the `Thread`, as described in the javadoc, and the `Thread` is now finished and killed.

Issue Links

• links to: GitHub Pull Request #58