Interface Segregation (I)

 1interface Worker {
 2    void work();
 3    void eat();
 4    void sleep();
 5}
 6class HumanWorker implements Worker { ... }
 7class RobotWorker implements Worker {
 8    public void work()  { /* real */ }
 9    public void eat()   { throw new UnsupportedOperationException(); }
10    public void sleep() { throw new UnsupportedOperationException(); }
11}