Print "hello world" every X seconds

Try doing this:

Timer t = new Timer();
t.schedule(new TimerTask() {
    @Override
    public void run() {
       System.out.println("Hello World");
    }
}, 0, 5000);

This code will run print to console Hello World every 5000 milliseconds (5 seconds). For more info, read https://docs.oracle.com/javase/1.5.0/docs/api/java/util/Timer.html

I figure it out with a timer, hope it helps. I have used a timer from java.util.Timer and TimerTask from the same package. See below:

TimerTask task = new TimerTask() {

    @Override
    public void run() {
        System.out.println("Hello World");
    }
};

Timer timer = new Timer();
timer.schedule(task, new Date(), 3000);

If you want to do a periodic task, use a ScheduledExecutorService. Specifically ScheduledExecutorService.scheduleAtFixedRate

The code:

Runnable helloRunnable = new Runnable() {
    public void run() {
        System.out.println("Hello world");
    }
};

ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
executor.scheduleAtFixedRate(helloRunnable, 0, 3, TimeUnit.SECONDS);

You can also take a look at Timer and TimerTask classes which you can use to schedule your task to run every n seconds.

You need a class that extends TimerTask and override the public void run() method, which will be executed everytime you pass an instance of that class to timer.schedule() method..

Here's an example, which prints Hello World every 5 seconds: -

class SayHello extends TimerTask {
    public void run() {
       System.out.println("Hello World!"); 
    }
}

// And From your main() method or any other method
Timer timer = new Timer();
timer.schedule(new SayHello(), 0, 5000);