Q2. How can you force garbage collection of an object?

          A.   Garbage collection cannot be forced.
         B.   Call System.gc().
         C.   Call System.gc() passing in a reference  to the object to be garbage collected.
         D.   Call Runtime.gc().
         E.    Set all references to the object to new values(null, for example).
      

Correct Answer: A

Explanation:

         A is correct. Garbage collection cannot be forced.
         B and D are not correct as calling System.gc() or Runtime.gc() is not 100 percent
         reliable, since the garbage collection thread might defer to a thread of higher 
         priority.
         C is incorrect as gc method does not take argument.
         E  makes object to be garbage collected while next time it refers.