Print "hello world" every X seconds

java timer

meiryo · Oct 16, 2012 · Viewed 256.5k times · Source

Lately I've been using loops with large numbers to print out Hello World:

int counter = 0;

while(true) {
    //loop for ~5 seconds
    for(int i = 0; i < 2147483647 ; i++) {
        //another loop because it's 2012 and PCs have gotten considerably faster :)
        for(int j = 0; j < 2147483647 ; j++){ ... }
    }
    System.out.println(counter + ". Hello World!");
    counter++;
}

I understand that this is a very silly way to do it, but I've never used any timer libraries in Java yet. How would one modify the above to print every say 3 seconds?

Answer

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);

Print "hello world" every X seconds

Answer

Related questions