import java.util.concurrent.atomic.*;
class Counter {
    int x = 0;
    /* "synchonized" auskommentieren, um Race-conditions zu sehen
       drinnen lassen, um die Langsamkeit von Synchronisation zu messen
       das hier ist allerdings ein Extremfall fuer Synchronsation */
    public synchronized void increment() {
        x++;
    }
    public int get() {
        return x;
    }
}
class Worker implements Runnable {
    private Counter counter;
    public Worker (Counter c) {
        counter = c;
    }
    public void run() {
        for(int i = 0; i < 100000000; i++)
            counter.increment();
    }
}
public class counter {
    public static final void main (String[] args) {
        Counter c1 = new Counter();
        Worker w1 = new Worker(c1);
        Worker w2 = new Worker(c1);
        if (false) { /* true fuer sequentielle Ausfuehrung */
            w1.run();
            w2.run();
        } else {
            Thread t1 = new Thread(w1);
            Thread t2 = new Thread(w2);
            t1.start();
            t2.start();
            try {
                t1.join();
                t2.join();
            } catch (InterruptedException x) {
            }
        }
        System.out.println("c1: x = " + c1.get());
    }
}