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    ExecutorService executor = Executors.newFixedThreadPool(5);
    executor.submit(new Runnable() {
        public void run() {
            for (int i = 0; i < 5; i++) {
              System.out.println("Start"+"  "+Thread.currentThread().getName());
              try {
                Thread.sleep(100);
              } catch (InterruptedException e) {
                e.printStackTrace();
              System.out.println("End!"+"  "+Thread.currentThread().getName());
    executor.shutdown();
    executor.awaitTermination(1, TimeUnit.SECONDS);
Here's my output:
    Start  pool-1-thread-1
    End!  pool-1-thread-1
    Start  pool-1-thread-1
    End!  pool-1-thread-1
    Start  pool-1-thread-1
    End!  pool-1-thread-1
    Start  pool-1-thread-1
    End!  pool-1-thread-1
    Start  pool-1-thread-1
    End!  pool-1-thread-1
My understanding is that in my code there're 5 threads in FixedThreadPool. So when I run my code, it's supposed to output all  5 threads, right? Or Am I misunderstanding something?
In my output thread-1 starts and end everytime but isn't it supposed to output all 5 threads when it loops in for loop?
Cause if only 1thread is doing the task then why do we even need 5 threads?
Is there any way all 5 threads can output on the console?(I'm a newbie)
You are posting only one Runnable so your ExecutorService runs one task. It will use only one thread. To use multiple threads you must call submit multiple times or you can call invokeAll with a Collection of runnables.
Something like this:
public void test() {
    int numberOfThreads = 5;
    ExecutorService executorService = Executors.newFixedThreadPool(numberOfThreads);
    for(int i=0; i<numberOfThreads; i++){
        executorService.submit(createRunnable());
private Runnable createRunnable() {
    return new Runnable() {
        @Override
        public void run() {
            for (int i = 0; i < 5; i++) {
                System.out.println("Start" + "  " + Thread.currentThread().getName());
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                System.out.println("End!" + "  " + Thread.currentThread().getName());
                Thanks, i got it. But can you please provide me some code for invokeAll. I don't know how to do it with invokeAll. It will be appreciated.
– user6857832
                Sep 30, 2016 at 14:50
                What do you exactly want? 5 threads, each of them printing out a start and an end message? Or 5 thread each having a 5 iteration loop, so each thread would print 5 start and 5 end messages?
– abbath
                Sep 30, 2016 at 16:18
                I want each thread having a 5 iteration loop, so each thread would print 5 start and 5 end messages.
– user6857832
                Sep 30, 2016 at 16:31
                But you said we can even do it with invokeAll. So how I can do with invokeAll.I don't want the whole code. I understand that execute.invokeAll() is all I've to do but what should I write inside invokeAll() parameters.
– user6857832
                Sep 30, 2016 at 16:36
        
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