删除bean后@Autowired（required = false）失败

Question

Steps to reproduce on https://github.com/nowszy94/Autowired-null

After removing bean from Spring context with BeanDefinitionRegistry:removeBeanDefinition method, @Autowired(required = false) spring throws error:

org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'helloService' is defined
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:698) ~[spring-beans-4.2.7.RELEASE.jar:4.2.7.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1175) ~[spring-beans-4.2.7.RELEASE.jar:4.2.7.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:284) ~[spring-beans-4.2.7.RELEASE.jar:4.2.7.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.2.7.RELEASE.jar:4.2.7.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.resolvedCachedArgument(AutowiredAnnotationBeanPostProcessor.java:508) ~[spring-beans-4.2.7.RELEASE.jar:4.2.7.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.access$200(AutowiredAnnotationBeanPostProcessor.java:115) ~[spring-beans-4.2.7.RELEASE.jar:4.2.7.RELEASE]
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:538) ~[spring-beans-4.2.7.RELEASE.jar:4.2.7.RELEASE]
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.2.7.RELEASE.jar:4.2.7.RELEASE]

Answer 1

Autowiring occurs at bean creation. If you did not have a helloService bean defined, then your spring application would not throw an exception when attempting to satisfy that dependency during bean creation. In your example you are removing the helloService bean from the application context after it has already been wired into your HelloController bean.