code: private static <T> T createCustomComponent(Class<T> componentType, String componentSpec,
              Map<String, String> configProperties, IPluginRegistry pluginRegistry) throws Exception {
          return createCustomComponent(componentType, componentSpec, configProperties, pluginRegistry, null);
      }
docs: Creates a custom component from information found in the properties file.
  @param componentType
  @param componentSpec
  @param configProperties
  @param pluginRegistry
  @throws Exception