Java Programming Tutorial - 58 - Abstract and Concrete Classes

package apples;

public class Fatty {

b banana = new b();

public void digest (b x) {

x.eat();

}

}

package apples;

 abstract public class b {

public abstract void eat(); 

}

package apples;

 class cup extends b  {

public void eat() {

System.out.println("this cup is great");

}

}

package apples;

public class apples extends b  {

public void eat() {

System.out.println("these apples are great");

}

 }