code: public JsonElement get(String name) throws JsonException {
          JsonElement result = nameValuePairs.get(name);
          if (result == null) {
              throw new JsonException("No value for " + name + ", in: " + this.toString());
          }
          return result;
      }
docs: Returns the value mapped by {@code name}, or throws if no such mapping exists.
  
  @throws JsonException if no such mapping exists.