Updated the entrySet() method to create MapEntry objects without a value, to save memory.  The value is pulled from the cache when the MapEntry.getValue() method is invoked.  Also updated the class to use the Ehcache interface to interact with the cache, rather than the concrete Cache class.
Updated the entrySet() method to create MapEntry objects without a value, to save memory.  The value is pulled from the cache when the MapEntry.getValue() method is invoked.  Also updated the class to use the Ehcache interface to interact with the cache, rather than the concrete Cache class.

eurekaclinical/javautil,arpost/javautil