Przykład

public static class ICThread extends Thread {
public void run() {
System.out.println( System.currentTimeMillis() );
}
}

public static void main( String[] args) {
(new ICThread()).start();
}

Rozwiązanie
Zamiast rozszerzać interfejs Thread, zaimplementuj interfejs Runnable.

public static class ICRunnable implements Runnable {
public void run() {
System.out.println( System.currentTimeMillis() );
}
}

public static void main( String[] args) {
(new Thread( new ICRunnable() )).start();
}