code: public String[] removeParameter(String name)
    {
      Map<String, String[]> map = getMap();
      String[] v = map.remove(name);
      if(v != null)
        rebuildQuery();    
      return v;
    }
docs: Remove parameter with given name and
  return its previous value.
  
  @param name parameter to remove
  @return previous value or null if parameter doesn't exist