Java OCA OCP Practice Question 2568

Question

What is the result of the following code? 

1:    public class Outer { 
2:    private int x = 24; 
3:    public int getX() { 
4:       String message = "x is "; 
5:       class Inner { 
6:          private int x = Outer.this.x; 
7:          public void printX() { 
8:             System.out.println(message + x); 
9:          } /*from   ww w.  j a v  a 2 s.  co  m*/
10:      } 
11:      Inner in = new Inner(); 
12:      in.printX(); 
13:      return x; 
14:   } 
15:   public static void main(String[] args) { 
16:      new Outer().getX(); 
17:   } }
  • A. x is 0.
  • B. x is 24.
  • C. Line 6 generates a compiler error.
  • D. Line 8 generates a compiler error.
  • E. Line 11 generates a compiler error.
  • F. An exception is thrown.


B.

Note

Outer.this.x is the correct way to refer to x in the Outer class.

In Java 7, the answer would have been D because you used to have to declare variables as final to use them in a local inner class.

In Java 8, this requirement was dropped and the variables only need to be effectively final, which means that the code would still compile if final were added.




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