multithreading Executors Defining a new ThreadPool

Example

A ThreadPool is an ExecutorService that executes each submitted task using one of possibly several pooled threads, normally configured using Executors factory methods.

Here is a basic code to initialize a new ThreadPool as a singleton to use in your app:

public final class ThreadPool {

    private static final String TAG = "ThreadPool";
    private static final int CORE_POOL_SIZE = 4;
    private static final int MAX_POOL_SIZE = 8;
    private static final int KEEP_ALIVE_TIME = 10; // 10 seconds
    private final Executor mExecutor;

    private static ThreadPool sThreadPoolInstance;

    private ThreadPool() {
        mExecutor = new ThreadPoolExecutor(
            CORE_POOL_SIZE, MAX_POOL_SIZE, KEEP_ALIVE_TIME,
            TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>());
    }

    public void execute(Runnable runnable) {
        mExecutor.execute(runnable);
    }

    public synchronized static ThreadPool getThreadPoolInstance() {
        if (sThreadPoolInstance == null) {
            Log.i(TAG, "[getThreadManagerInstance] New Instance");
            sThreadPoolInstance = new ThreadPool();
        }
        return sThreadPoolInstance;
    }
}

You have two ways to call your runnable method, use execute() or submit(). the difference between them is that submit() returns a Future object which allows you a way to programatically cancel the running thread when the object T is returned from the Callable callback. You can read more about Future here