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

I would recommend looking at the Executors framework first, and then look into the CompletionService.

Then you can write something like this:

ExecutorService executor = Executors.newFixedThreadPool(maxThreadsToUse);
CompletionService completion = new ExecutorCompletionService(executor);
for (each sub task) {
    completion.submit(new SomeTaskYouCreate())
}
// wait for all tasks to complete.
for (int i = 0; i < numberOfSubTasks; ++i) {
     completion.take(); // will block until the next sub task has completed.
}
executor.shutdown();