1 interface IShow{ 2     public void show(String str); 3 } 4  5 class ShowA implements IShow{     6     public void show(String str) { 7         System.out.println(str+" is very high!");         8     }     9 };10 11 class ShowB implements IShow{    12     public void show(String str) {13         System.out.println(str+" is very rich!");        14     }    15 };16 17 class ShowC implements IShow{    18     public void show(String str) {19         System.out.println(str+" is very handsome!");        20     }    21 };

1         String str = "Jack";2         IShow showA = new ShowA();3         IShow showB = new ShowB();4         IShow showC = new ShowC();5         showA.show(str);6         showB.show(str);7         showC.show(str);