Question

I want to use a bounded queue for a ThreadPoolExecutor but I want to use my custom RejectedExecutionExceptionHandler. I would need to do that so that I can put rejected tasks to a separate queue and after a while try to resubmit them.
Is a custom RejectedExecutionExceptionHandler the solution to my problem? If yes how do I implement one?
Or else what would be the best way to deal with my issue?

Answer 1

I would use an unbounded queue as this will queue tasks which cannot be run for later use. I would sue Executors.newFixedThreadPool in your case. You may be interested in what this does

public static ExecutorService newFixedThreadPool(int nThreads) {
    return new ThreadPoolExecutor(nThreads, nThreads,
                                  0L, TimeUnit.MILLISECONDS,
                                  new LinkedBlockingQueue<Runnable>());
}

Note: it uses an unbounded queue.

IMHO the simplest/best way to deal with the problem is to run the task in the current thread.

This ensures all tasks are performed in a timely manner using the current thread where there is no spare background threads.

new RejectedExecutionHandler() {
    @Override
    public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {
        r.run();
    }
}