public class CounterThread2 extends Thread {

public static void main(String[] args) {
Thread[] threads = new Thread[10];
for (int i = 0; i < 10; ++i) {
threads[i] = new CounterThread2("Counter-" + i);
}
for (Thread t : threads) {
t.start();
}

// Wait for all threads to end
boolean done = false;
while (!done) {
boolean alive = false;
for (int i = 0; i < 10; ++i) {
if (threads[i].isAlive()) alive = true;
}
done = !alive;
}
System.out.println("End - end - end");
}

// Counter variable
private static volatile Integer counter = 0;

// Object attributes
private String threadName;

public CounterThread2(String name) {
super(name);
this.threadName = name;
}

public void run() {
for (int i = 0; i < 100000; i++) {
synchronized(counter) {
counter++;
}
System.out.println("Count " + counter + " (" + threadName + ")");
}
}
}