Timer loop displaying 0 ticks instead of 60

Question

I have the following code:

public void run(){
    long lastTime=System.nanoTime();
    final double amountOfTicks=60.0;
    double ns=1000000000/amountOfTicks;
    double delta=0;
    int updates=0;
    int frames=0;
    long timer=System.currentTimeMillis();
    while(running){
        long now=System.nanoTime();
        delta+=(now-lastTime)-ns;
        lastTime=now;
        if(delta>=1){
            tick();
            updates++;
            delta--;
        }
        render();
        frames++;

        if((System.currentTimeMillis()-timer)>1000){
            timer+=1000;
            System.out.println(updates+" Ticks, FPS "+frames);
            updates=0;
            frames=0;
        }
    }
    stop();
}

This should display "60 Ticks, FPS 9000000", but instead it displays "0 Ticks, FPS 9000000". Why is this and how can I fix it?

Answer 1

After installing NetBeans for its debugger, I've found that delta was a negative number. As it turns out, it was a simple typographical error.

delta+=(now-lastTime)-ns; should be delta+=(now-lastTime)/ns;