code: protected AbstractApplicationContext resolveByConfig(Component component,
                                                           ApplicationContext parent) {
          String appConfig = component.getManifestAttribute(APP_CONFIG);
          Class appConfigClass;
          try {
              appConfigClass = Class.forName(appConfig, true, component.getClassLoader());
          } catch (ClassNotFoundException e) {
              throw new ApplicationConfigurationException("The app config class: " + appConfig
                                                          + " can't be loaded by the component:" + component, e);
          }
          AnnotationComponentApplicationContext context = new AnnotationComponentApplicationContext(component, parent);
          context.register(appConfigClass);
          return context;
      }
docs: Annotation方式解析独立的应用程序包
  
  @param component 组件对象
  @return 加载出来的应用程序上下文