ExecutorService and awaitTermination

Question

I have an executor service(MainES), which in turn starts a thread. This thread in turn use an executor service to execute(S1) say 10 threads(T1-T10). T1-T10 say sleeps for 20 secs.
My question is when I awaitTermination on the MainES, why does it return true though the threads in S1 have not completed? Why does it not wait for all the tasks in S1 to finish? They are the child threads.
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
public class TestES {
    /** Creates a new instance of TestES */
    public TestES() {
    public static void main(String[] args) {
        TestES testEs = new TestES();
        testEs.process();
    public void process() {
        ExecutorService esMain = Executors.newCachedThreadPool();
        esMain.execute(new Handler());
        esMain.shutdown();
        boolean result=false;
        try {
            result = esMain.awaitTermination(1000, TimeUnit.SECONDS);
        } catch (InterruptedException ex) {
            ex.printStackTrace();
        System.out.println("awaitTermination? " + result);
    class Handler implements Runnable {
        Handler() {
        public void run() {
            ExecutorService es = Executors.newCachedThreadPool();
            for(int i=0;i<10;i++) {
                es.execute(new HandlerChild());
            es.shutdown();
    class HandlerChild implements Runnable {
        HandlerChild() {
        public void run() {
            // read and service request
            try {
                Thread.sleep(100);
                System.out.println("HandlerChild........"+Thread.currentThread());
            } catch (InterruptedException ex) {
                ex.printStackTrace();
}

Answer 1

ForumKid2 wrote:
I have two long queries that run about 30 seconds each. Without the ExecutorService it takes approximately 1 minute to get the results single threaded.
I setup the above logic to call the queries and its takes the same amount of time (give or take a few milliseconds) to return the results. In essence, the queries should run at the same time therefore taking approximately half the time which would be around 30 seconds. That's why I think I am doing something wrong.If your examples are anything to go by, you most likely do the work in the constructor. Don't do that, do the work in the call()-method. That is what it is there for. If you do the work in the constructor, the calling thread will simply do the work before adding it to the executorservice, robbing you of the benefit of that service.