SCJP題庫第034題

Which four statements are true? (Choose four.)

A. Has-a relationships should never be encapsulated.

B. Has-a relationships should be implemented using inheritance.

C. Has-a relationships can be implemented using instance variables.

D. Is-a relationships can be implemented using the extends keyword.

E. Is-a relationships can be implemented using the implements keyword.

F. The relationship between Movie and Actress is an example of an is-a relationship.

G. An array or a collection can be used to implement a one-to-many has-a relationship.

Ans:C D E G

解說:

那四個敘述是正確的？

Has-a 關係應該永遠不能被封裝

Has-a 關係應該以繼承的方式實作

Has-a 關係可以用物件變數的方式被實現出來

Is-a關係可用extends關鍵字實現出來

Is-a關係可用implements關鍵字實現出來

電影和女演員間的關係是一個Is-a關係的例子

一個陣列或一個集合可以被用來實作一對多的has-a關係