code: public static void containsKey( Map<?, ?> argument,
                                      Object key,
                                      String name ) {
          isNotNull(argument, name);
          if (!argument.containsKey(key)) {
              throw new IllegalArgumentException(CommonI18n.argumentDidNotContainKey.text(name, getObjectName(key)));
          }
      }
docs: Check that the map contains the key
  
  @param argument Map to check
  @param key Key to check for, may be null
  @param name The name of the argument
  @throws IllegalArgumentException If map is null or doesn't contain key