Ejemplo

public class ThreadedClass extends java.lang.Thread {
public ThreadedClass () {
super ();
}

public void start () {
//..
}
public void sleep (long millis) {
//..
}
}


Solución
Proporcione un método run().

public class ThreadedClass extends java.lang.Thread {
public ThreadedClass () {
super ();
}

public void start () {
//..
}
public void sleep (long millis) {
//..
}
public void run () {
//..
}
}