Java OCA OCP Practice Question 304

Question

Which of the following is not a possible output of this code, assuming it runs to completion? 

package store; /*www  .j  av a 2s  .  c o m*/
public class Toy { 
   public void play() { 
      System.out.print("play-"); 
   } 
   public void finalize() { 
      System.out.print("clean-"); 
   } 
   public static void main(String[] args) { 
      Toy car = new Toy(); 
      car.play(); 
      System.gc(); 
      Toy doll = new Toy(); 
      doll.play(); 
   } 
}
  • A. play-
  • B. play-play-
  • C. play-play-clean-
  • D. play-play-clean-clean- 


A.

Note

Remember that garbage collection is not guaranteed to run on demand.

If it doesn't run at all, Option B would be output.

If it runs at the requested point, Option C would be output.

If it runs right at the end of the main() method, Option D would be output.

Option A is the correct answer because play is definitely called twice.

Note that you are unlikely to see all these scenarios if you run this code because we have not used enough memory for garbage collection to be worth running.

You need to be able to answer what could happen regardless of it being unlikely.




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