Is it dangerous to use while to pause the entire java program?

Question

Ok, I'm pretty new to java programming, but I really need to pause program execution until some event happens:

while(!isItHappened());
doSomethingAfterItHappend();

What is the best way to avoid this ugly situation?

Answer 1

Not really dangerous (thanks to preemptive multitasking), but a waste of resources. Use a CountDownLatch with a count of 1, like startSignal in the example. Or dig deeper and implement your own waiting mechanics using Object's wait and notify / notifyAll methods.

Answer 2

I compared CPU usage.

1. CPU usage 13-15%:

   while(!isItHappened());
   doSomethingAfterItHappend();
   

2. CPU usage well 0-1%:

   synchronized(itHappend) {
       itHappened.wait();   
   }
   doSomething();
   

So second piece of code is obviously better. Many thanks to duckstep.