docs: public static Object removeFromMapValues(final Map map, final Object value)
          {
          synchronized (map)
              {
              final Collection entries = map.entrySet();
              for (final Iterator iter = entries.iterator(); iter.hasNext();)
                  {
                  final Map.Entry entry = (Entry) iter.next();
                  if (entry.getValue().equals(value))
                      {
                      final Object key = entry.getKey();
                      iter.remove();
                      return key;
                      }
                  }
              return null;
              }
          }