Wait until child threads completed : Java

Question

Problem description : -

Step 1: Take input FILE_NAME from user at main thread.

Step 2: Perform 10 operations on

Answer 1

Check if all child threads are dead, every n seconds. Simple, yet effective method:

        boolean allDead=false;
        while(! allDead){
            allDead=true;
            for (int t = 0; t < threadCount; t++)
                if(threads[t].isAlive())    allDead=false;
            Thread.sleep(2000);

        }