code: private void add( final List<String> arguments,
                        final String argument )
      {
          if( argument != null && argument.trim().length() > 0 )
          {
              arguments.add( argument );
          }
      }
docs: Adds an argumentto a list of arguments by skipping null or empty arguments.
  
  @param arguments list to which the arguments should be added
  @param argument  argument to be added (can be null or empty)