long lastTime = System.currentTimeMillis(); //Последнее время в ms
int fps = 0; //Счетчик FPS
while (true) { //Допустим, игровой цикл
    if (System.currentTimeMillis() - lastTime >= 1000L) {
       System.out.println(fps + " fps");
       fps = 0;
       lastTime = System.currentTimeMillis();
    }
    fps++;
}

global.dragged = -1;
sx = 0;  
sy = 0;

global.dragged = id;
sx = x - mouse_x;  
sy = y - mouse_y;

global.dragged = -1;

if (global.dragged == id) {  
    x = mouse_x + sx;  
    y = mouse_y + sy;  
}

if (DateTime.Now.Seconds / 4 % 2 == 0) UpdateWorld();