code: public static void checkStringArgument(String str, String variableName) {
      if (null == str) {
        throw new NullPointerException(ExceptionMessageMap.getMessage("000001")
            + "  { variableName=[" + variableName + "] }");
      }
      if (str.length() == 0) {
        throw new IllegalArgumentException(ExceptionMessageMap.getMessage("000001")
            + "  { variableName=[" + variableName + "] }");
      }
    }
docs: Checks a <code>String</code> argument to make sure it is not null and contains one or more
  characters. If the <code>String</code> is null, a <code>NullPointerException</code> is
  thrown. If the <code>String</code> has length zero, an <code>IllegalArgumentException</code>
  is thrown.
  
  @param str
  The string to check.
  @param variableName
  The name of the variable being checked; for use in exception messages.