The time complexity of any isEmpty() method implementation should be
O(1) whereas some implementations of size() can be O(n). Thus, using
this rule provides performance benefits.
jSparrow Cleanup

Change-Id: I18240d7aa9e939e45c99e225f2bd1f35f6a7213e
Signed-off-by: Ardit Ymeri <ardit.ymeri@splendit.at>