code: public String getFirstParam(String paramName) {
          Collection<String> values = this.params.get(paramName);
          if(values == null || values.isEmpty()) {
              return null;
          } else {
              return values.iterator().next();
          }
      }
docs: gets first value of specific param.
  @param paramName    : name of the param to fetch value for
  @return  : first value in the collection  corresponding param name if found, otherwise <code>null</code>