ExecutorService make all threads wait

Question

Is there an simple/elegant way to make all threads created by ExecutorService to wait() ?

My current solution is to add a flag and pause make the threads wait with it like so:

public class task implements Runnable {
        
        static boolean flag;
         
        public void run()
        {
            while(true){
                if(flag){
                    wait();
                }else{
                    /* do stuff */
                    .
                    .
                    .
                }
            }
        }
    }

But in this way I can only make thread wait at the end of an iteration of its task and It's seem to be unnecessarily complicated.