Java while loop and Threads!

volatile boolean stop = false;

Runtime.getRuntime().addShutdownHook(new Thread("shutdown thread") {

        public void run()
        {
            stop = true;
        }
});

boolean stop = false;
final Object event = new Object();

Runtime.getRuntime().addShutdownHook(new Thread("shutdown thread") {

        public void run()
        {
            synchronized(event)
            {
               stop = true;
               event.notifyAll();
            }
        }
});

// ... and in your polling loop ...
synchronized(event)
{
    while(!stop)
    {
        // ... do JDBC access ...
        try
        {
            // wait 30 seconds, but break out as soon as the event is fired.
            event.wait(30000);
        }
        catch(InterruptedException e)
        {
            // Log a message and exit. Never ignore interrupted exception.
            break;
        }
    }
}

public class Service implements Runnable {

    private boolean shouldStop = false;

    public synchronized stop() {
        shouldStop = true;
        notify();
    }

    private synchronized shouldStop() {
        return shouldStop;
    }

    public void run() {
        setUp();
        while (!shouldStop()) {
            doStuff();
            sleep(60 * 1000);
        }
    }

    private synchronized sleep(long delay) {
        try {
            wait(delay);
        } catch (InterruptedException ie1) {
            /* ignore. */
        }
    }

}