code: public synchronized ExamReactor prepareReactor(Class<?> _testClass, Object testClassInstance) {
          this.currentTestClass = _testClass;
          this.reactor = createReactor(_testClass);
          testClasses.add(_testClass);
          try {
              addConfigurationsToReactor(_testClass, testClassInstance);
          }
          catch (IllegalAccessException exc) {
              throw new TestContainerException(exc);
          }
          catch (InvocationTargetException exc) {
              Throwable cause = exc.getCause();
              if (cause instanceof AssertionError) {
                  throw (AssertionError)cause;
              } 
              else {
                  throw new TestContainerException(cause);
              }
          }
          return reactor;
      }
docs: Prepares the unstaged reactor for the given test class instance. Any configurations from
  {@code Configuration} methods of the class are added to the reactor.
  
  @param _testClass
  test class
  @param testClassInstance
  instance of test class
  @return reactor