Regarding daemon thread providing some service to non daemon thread

Question

I have one query that is I have developed a code below of multiple threads named thread one and thread two, below is the code ..

class multip implements Runnable {

Answer 1

The question is about of how the daemon thread will provide the service to non daemon thread

I would use an executor service. If you want to return a value from the daemon thread, you can use a Callable instead of a Runnable.

// creating a thread pool.
ExecutorService service = Executors.newSingleThreadExecutor(new ThreadFactory() {
    @Override
    public Thread newThread(Runnable r) {
        // creating a thread.
        Thread two = new Thread(r, "two");
        // making it a daemon thread.
        two.setDaemon(true);
        return two;
    }
});

for(int i=0;i<10;i++)
    // creating a task and submitting it.
    service.submit(new Runnable() {
        @Override
        public void run() {
            System.out.println("["+Thread.currentThread().getName()+"] - Hello World.");
            Thread.yield();
        }
    });
service.shutdown();

prints

[two] - Hello World.
[two] - Hello World.
[two] - Hello World.

First it creates a thread pool with a work queue. The thread pool has a factor which creates threads, in this case with a given name which is a daemon.

Secondly there is a loop which add 10 tasks to the queue for the executors thread(s) to execute.

Finally it stops the service when it has finished with it (this is rarely needed)