Java OCA OCP Practice Question 909

Question

Which of the following are legal clone() methods in a class called MyClass that extends Object? 

A. public Object clone() { 
        return super.clone(); 
   } /* w ww . ja  va  2  s .co m*/

B. public Object clone()throws CloneNotSupportedException { 
        return super.clone(); 
   } 
C. public MyClass clone() { 
        return (MyClass)super.clone(); 
   } 
D. public MyClass clone() throws CloneNotSupportedException { 
        return (MyClass)super.clone(); 
   } 



B, D.

Note

The CloneNotSupportedException must be dealt with, so A and C are wrong.

The version being overridden (in Object) has return type Object, so prior to release 5.0 the return type in D would be illegal; however, now that covariant returns are legal, D is allowed.




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