Make KeyInValueHashMap compliant with JDK 1.7

* Original method produces a name clash with no override whilst the
  replacement does adequately override the super implementation.
Remove override annotations to support JDK 1.6

* Since Designer should be available for both JDK 1.6 and 1.7, avoid
  Override annotations on methods specifically added in 1.7 since these
  generate compilers errors when using JDK 1.6