Java OCA OCP Practice Question 690

Question

What is the output of the following? 

5:  StringBuilder line = new StringBuilder("-"); 
6:  StringBuilder anotherLine = line.append("-"); 
7:  System.out.print(line == anotherLine); 
8:  System.out.print(" "); 
9:  System.out.print(line.length());
  • A. false 1
  • B. false 2
  • C. true 1
  • D. true 2


D.

Note

A StringBuilder is mutable, so the length is two after line 6 completes.

The StringBuilder methods return a reference to the same object so you can chain method calls.

Therefore, line and anotherLine refer to the same object.

Line 7 prints true.

Then on line 9, both references point to the same object of length 2, and Option D is correct.




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