code: public String getOptionValue(String opt, String defaultValue)
      {
          String answer = getOptionValue(opt);
  
          return (answer != null) ? answer : defaultValue;
      }
docs: Retrieve the first argument, if any, of an option.
  
  @param opt name of the option
  @param defaultValue is the default value to be returned if the option
  is not specified
  @return Value of the argument if option is set, and has an argument,
  otherwise <code>defaultValue</code>.