public class RandomThread extends  Thread{

    static AtomicReference<Double> result = new AtomicReference<Double>(3.0);//test with 2, 0, -1, 58 : it's fun

    @Override
    public void run() {

        try {
            sleep((long)Math.random()*100);
            Double cacheResult = result.get();
            result.compareAndSet(cacheResult, cacheResult+Math.sin(cacheResult.doubleValue()));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }