ScheduledThreadPoolExecutor vs. Timer (Java)

I read that the Timer object was replaced by the ScheduleThreadPoolExecutor class in a book on multi-threaded programming or maybe it was a book on design patterns. I stuck this information away in the back of my mind as I had previously written some code using the Timer class, and had been given Spring beans using timers.

Recently I started working on a something similar to my existing code using the Timer object. Since it was so similar I thought I would just copy my other project, modify it slightly, and be done with it. I ran into a problem where the execution of the code seemed to just stop without terminating the thread and no error message.

I switched to the Executor class and was able to get an error message. Apparently the Timer object has a problem with unchecked exceptions.

Then I switched over to the ScheduledThreadPoolExecutor - same thing. Execution hangs. No error message.

Here is a simple example of Executor:

public class ExampleExecutor
{
    private static final int NTHREADS = 100;
    private static final Executor exec
            = Executors.newFixedThreadPool(NTHREADS);
    
    public static void main(String args[]) {

        while (true) {

            Runnable task = new Runnable() {
                public void run() {
                    doMyThing();
                }
                
                private void doMyThing(){
                   //do something
                }
                
            };
            
            exec.execute(task);        
        }
    }
}