Is it safe to create javax.ejb.Timers in loop

Question

Is it "safe" to code the following when processing javax.ejb.Timer(s)

Timer timer = null;

for (Object object  : timerService.getTimers()) {               

  timer = (Timer)object;

  timer.cancel();
  timer = timerService.createTimer(timerStatupInterval, timerInterval, timerName);

}

what i am concerned about is the getTimers() call returning the newly created timers from within the loop

will that EVER Happen?

score 1 · Accepted Answer · edited May 23 '17 at 10:25

Is it safe to create javax.ejb.Timers in loop ?

No, takes in mind that the different implementations of Collection interface in java.util package don't allow to modify the list structure once the iterator is created, when the list structure is modified this kind of iterator called (fail-fast) will throw a ConcurrentModificationException.

According to the specification, the getAllTimer() method returns a java.util.Collection, therefore, we can assume that the list structure is not modified.

what i am concerned about is the getTimers() call returning the newly created timers from within the loop will that EVER Happen?

There is still the possibility that the getAllTimer() implementation does not modify the list structure, (may be the new Timer instance is created in an different collection), but if this was the case, you can be sure that the current loop iterator won't see the new collection element.

Is it safe to create javax.ejb.Timers in loop

1 Answers1