Fixing NPE in AbstractNamedValueMethodArgumentResolver

[dekelpilli]

Upgrading one of our apps to Spring Boot 2.2.0.RELEASE (with Spring 5.2.0.RELEASE) is blocked by a null pointer exception in AbstractNamedValueMethodArgumentResolver that occurs whenever we are trying to receive a message via an SqsListener.

My approach is to undo 5b3b0b1#diff-ba4bc09499d8cbf059d24ea9c6062b9cL82

[pivotal-issuemaster]

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[rstoyanchev]

@dekelpilli, I can make this more lenient again to avoid a NPE but it does mean that some code somewhere is creating the argument resolver by passing null as the ConversionService. Can you provide a stack trace or help me to understand which project is creating the argument resolver?

[dekelpilli]

@rstoyanchev Sure, I'll try to do that at work tomorrow. The problem is that the stacktrace is from when the exception is thrown, not when the resolver is built. I'll try to run it locally with a breakpoint and provide that as well.

[rstoyanchev]

Right, I would only use the stacktrace as a clue. If you can point me to the code that's creating the resolver that would be quite sufficient.

[dekelpilli]

Creation stacktrace (this is from a test running locally, but the issue first appeared in a live dev server):

at org.springframework.messaging.handler.annotation.support.AbstractNamedValueMethodArgumentResolver.<init>(AbstractNamedValueMethodArgumentResolver.java:78)
	at org.springframework.messaging.handler.annotation.support.HeaderMethodArgumentResolver.<init>(HeaderMethodArgumentResolver.java:54)
	at org.springframework.cloud.aws.messaging.listener.QueueMessageHandler.initArgumentResolvers(QueueMessageHandler.java:86)
	at org.springframework.messaging.handler.invocation.AbstractMethodMessageHandler.afterPropertiesSet(AbstractMethodMessageHandler.java:236)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1862)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1799)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:595)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:212)
	at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.resolveBeanReference(ConfigurationClassEnhancer.java:393)
	at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:366)
	at org.springframework.cloud.aws.messaging.config.annotation.SqsConfiguration$$EnhancerBySpringCGLIB$$5b2bea87.queueMessageHandler(<generated>)
	at org.springframework.cloud.aws.messaging.config.annotation.SqsConfiguration.simpleMessageListenerContainer(SqsConfiguration.java:70)
	at org.springframework.cloud.aws.messaging.config.annotation.SqsConfiguration$$EnhancerBySpringCGLIB$$5b2bea87.CGLIB$simpleMessageListenerContainer$0(<generated>)
	at org.springframework.cloud.aws.messaging.config.annotation.SqsConfiguration$$EnhancerBySpringCGLIB$$5b2bea87$$FastClassBySpringCGLIB$$36664d62.invoke(<generated>)
	at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244)
	at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:363)
	at org.springframework.cloud.aws.messaging.config.annotation.SqsConfiguration$$EnhancerBySpringCGLIB$$5b2bea87.simpleMessageListenerContainer(<generated>)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
	at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:640)
	at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:625)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1338)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1177)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:557)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:517)
	at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:323)
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:321)
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:879)
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:878)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141)
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747)
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:315)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215)
	at [our public static void main SpringApplication.run() call]

Exception stacktrace:

Unhandled exception from message handler method
java.lang.NullPointerException: null
at org.springframework.messaging.handler.annotation.support.AbstractNamedValueMethodArgumentResolver.resolveArgument(AbstractNamedValueMethodArgumentResolver.java:111)
at org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:117)
at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:148)
at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:116)
at org.springframework.messaging.handler.invocation.AbstractMethodMessageHandler.handleMatch(AbstractMethodMessageHandler.java:565)
at org.springframework.messaging.handler.invocation.AbstractMethodMessageHandler.handleMessageInternal(AbstractMethodMessageHandler.java:520)
at org.springframework.messaging.handler.invocation.AbstractMethodMessageHandler.handleMessage(AbstractMethodMessageHandler.java:454)
at org.springframework.cloud.aws.messaging.listener.SimpleMessageListenerContainer.executeMessage(SimpleMessageListenerContainer.java:205)
at org.springframework.cloud.aws.messaging.listener.SimpleMessageListenerContainer$MessageExecutor.run(SimpleMessageListenerContainer.java:342)
at org.springframework.cloud.aws.messaging.listener.SimpleMessageListenerContainer$SignalExecutingRunnable.run(SimpleMessageListenerContainer.java:397)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)

[rstoyanchev]

Thanks, it's right here where the header resolver is created.

I've processed the change to fall back on a default ConversionService as it did before but I have removed the @Nullable annotations to continue to indicate it should be passed in. Ideally QueueMessageHandler should have a configurable ConversionService like this here.