code: public static void checkArgument(boolean b, String message, Object... args) {
          if (!b) {
              throwEx(message, args);
          }
      }
docs: Check the specified boolean argument. Throws an IllegalArgumentException with the specified message if {@code b} is false.
  Note that the message may specify argument locations using "%s" - for example,
  {@code checkArgument(false, "Got %s values, expected %s", 3, "more"} would throw an IllegalArgumentException
  with the message "Got 3 values, expected more"
  
  @param b       Argument to check
  @param message Message for exception. May be null.
  @param args    Arguments to place in message