Create threads in java to run in background

Question

I want to spawn a Java thread from my main java program and that thread should execute separately without interfering with the main program. Here is how it should be:

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Answer 1

And if you like to do it the Java 8 way, you can do it as simple as this:

public class Java8Thread {

    public static void main(String[] args) {
        System.out.println("Main thread");
        new Thread(this::myBackgroundTask).start();
    }

    private void myBackgroundTask() {
        System.out.println("Inner Thread");
    }
}

Answer 2

One straight-forward way is to manually spawn the thread yourself:

public static void main(String[] args) {

     Runnable r = new Runnable() {
         public void run() {
             runYourBackgroundTaskHere();
         }
     };

     new Thread(r).start();
     //this line will execute immediately, not waiting for your task to complete
}

Alternatively, if you need to spawn more than one thread or need to do it repeatedly, you can use the higher level concurrent API and an executor service:

public static void main(String[] args) {

     Runnable r = new Runnable() {
         public void run() {
             runYourBackgroundTaskHere();
         }
     };

     ExecutorService executor = Executors.newCachedThreadPool();
     executor.submit(r);
     // this line will execute immediately, not waiting for your task to complete
     executor.shutDown(); // tell executor no more work is coming
     // this line will also execute without waiting for the task to finish
    }

Answer 3

This is another way of creating a thread using an anonymous inner class.

    public class AnonThread {
        public static void main(String[] args) {
            System.out.println("Main thread");
            new Thread(new Runnable() {
                @Override
                public void run() {
                System.out.println("Inner Thread");
                }
            }).start();
        }
    }