code: public QueryStringBuilder addParameterLists(final Map<String, List<String>> params)
     {
        if (params != null)
        {
           for (Entry<String, List<String>> entry : params.entrySet())
           {
              List<String> values = null;
              if (entry.getValue() != null)
              {
                 values = new ArrayList<String>(entry.getValue());
              }
              parameters.put(entry.getKey(), values);
           }
        }
        return this;
     }
docs: Add parameters from the given map of name=value pairs. For parameters with more than one value, each value will be
  appended using the same name. If a parameter already exists, append new values to the existing list of values for
  that parameter.