jobExecutor.shutdown();
        assertEquals(2, shutdownCount.get());

        jobExecutor.shutdown();
        assertEquals(3, shutdownCount.get());
    }

    public void test_shutdownListener_interface() {
        // Test anonymous ShutdownListener implementation
        final AtomicBoolean flag = new AtomicBoolean(false);
        ShutdownListener listener = new ShutdownListener() {
            @Override