code: public static boolean getBoolean(JsonObject object, String field, boolean defaultValue) {
          final JsonValue value = object.get(field);
          if (value == null || value.isNull()) {
              return defaultValue;
          } else {
              return value.asBoolean();
          }
      }
docs: Returns a field in a Json object as a boolean.
  
  @param object the Json Object
  @param field the field in the Json object to return
  @param defaultValue a default value for the field if the field value is null
  @return the Json field value as a boolean