I am wondering if this is the best way to do this. I have about 500 threads that run indefinitely, but Thread.sleep for a minute when done one cycle of processing.

   ExecutorService es = Executors.newFixedThreadPool(list.size()+1);
   for (int i = 0; i < list.size(); i++) {
      es.execute(coreAppVector.elementAt(i)); //coreAppVector is a vector of extends thread objects
   }

The code that is executing is really simple and basically just this

class aThread extends Thread {
   public void run(){
      while(true){
         Thread.sleep(ONE_MINUTE);
         //Lots of computation every minute
      }
   }
}

I do need a separate threads for each running task, so changing the architecture isn't an option. I tried making my threadPool size equal to Runtime.getRuntime().availableProcessors() which attempted to run all 500 threads, but only let 8 (4xhyperthreading) of them execute. The other threads wouldn't surrender and let other threads have their turn. I tried putting in a wait() and notify(), but still no luck. If anyone has a simple example or some tips, I would be grateful!

Well, the design is arguably flawed. The threads implement Genetic-Programming or GP, a type of learning algorithm. Each thread analyzes advanced trends makes predictions. If the thread ever completes, the learning is lost. That said, I was hoping that sleep() would allow me to share some of the resources while one thread isn't "learning"