code: private void addConfigurationsToReactor(Class<?> testClass, Object testClassInstance)
          throws IllegalAccessException, InvocationTargetException {
          numConfigurations = 0;
          Method[] methods = testClass.getMethods();
          for (Method m : methods) {
              if (isConfiguration(m)) {
                  // consider as option, so prepare that one:
                  reactor.addConfiguration(((Option[]) m.invoke(testClassInstance)));
                  numConfigurations++;
              }
          }
          failOnUnusedConfiguration(testClass.getDeclaredMethods());
      }
docs: Scans the current test class for declared or inherited {@code @Configuration} methods and
  invokes them, adding the returned configuration to the reactor.
  
  @param testClass
  test class
  @param testClassInstance
  instance of test class
  @throws IllegalAccessException
  when configuration method is not public
  @throws InvocationTargetException
  when configuration method cannot be invoked