code: public static void checkNotNullOrEmpty(String param, String errorMessagePrefix) throws
              IllegalArgumentException {
          checkNotNull(param, errorMessagePrefix);
          checkArgument(!param.isEmpty(), (errorMessagePrefix != null ?
                  errorMessagePrefix : "Parameter") + " must not be empty.");
      }
docs: Check that a string parameter is not null or empty and throw IllegalArgumentException with a
  message of errorMessagePrefix + " must not be empty." if it is empty, defaulting to
  "Parameter must not be empty".
  
  @param param              the string to check
  @param errorMessagePrefix the prefix of the error message to use for the
  IllegalArgumentException if the parameter was null or empty
  @throws IllegalArgumentException if the string is null or empty