code: public Set<Map.Entry<List<K>,Double>> entrySet() {
      return ErasureUtils.<Set<Map.Entry<List<K>,Double>>>uncheckedCast(entrySet(new HashSet<Map.Entry<Object,Double>>(), zeroKey, true));
    }
docs: Returns the set of entries in the GeneralizedCounter.
  Here, each key is a read-only {@link
  List} of size equal to the depth of the GeneralizedCounter, and
  each value is a {@link Double}.  Each entry is a {@link java.util.Map.Entry} object,
  but these objects
  do not support the {@link java.util.Map.Entry#setValue} method; attempts to call
  that method with result
  in an {@link UnsupportedOperationException} being thrown.