Question

I got a fixed number of threads. I want each thread to run three Runnables, one after another. Here’s some pseudocode to explain:

Thread[] threads = new Thread[4];

for (int i = 0; i < threads.length; i++) {
    // Set the first tasks.
    threads[i] = new Thread(new FirstRunnable());
    threads[i].start();
}

for (int i = 0; i < threads.length; i++)
    threads[i].join(); // wait until the first tasks are done

for (int i = 0; i < threads.length; i++) {
    // Set the second task.
    threads[i].setRunnable(new SecondRunnable());
    threads[i].start();
}

for (int i = 0; i < threads.length; i++)
    threads[i].join(); // wait until the second tasks are done

...

Using a ThreadPool sounds way overkill, especially since I’m headed for performance, performance, performance. What’s the best way to implement this in Java?

Answer 1

Whenever you see new Thread(...).start(), make use of the Executors framework. In particular, make use of Executors.newFixedThreadPool(...).