NPE in LoadTimeWeavingConfiguration: loadTimeWeaver() called too early [SPR-14931]

[spring-projects-issues]

Marvin Luchs opened SPR-14931 and commented

The enableLTW property of LoadTimeWeavingConfiguration is null on instantiation and is set by setImportMetadata via the ConfigurationClassPostProcessor.ImportAwareBeanPostProcessor BeanPostProcessor. However, the loadTimeWeaver method of LoadTimeWeavingConfiguration, which uses enableLTW, is called before ImportAwareBeanPostProcessor can set enableLTW to an appropriate value which leads to a NullPointerException.

The loadTimeWeaver method call seems to originate from LoadTimeWeaverAwareProcessor's postProcessBeforeInitialization method.

I should mention that I upgraded the spring-framework dependency of my project from 3.2.0 to 4.3.4 and that my configuration worked with 3.2.0.

{CODE}
25252 [RMI TCP Connection(3)-127.0.0.1] INFO org.springframework.beans.factory.support.DefaultListableBeanFactory - Overriding bean definition for bean 'loadTimeWeaver' with a different definition: replacing [Generic bean: class [org.springframework.context.weaving.DefaultContextLoadTimeWeaver]; scope=; abstract=false; lazyInit=false; autowireMode=0; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=null; factoryMethodName=null; initMethodName=null; destroyMethodName=null] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.context.annotation.LoadTimeWeavingConfiguration; factoryMethodName=loadTimeWeaver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/context/annotation/LoadTimeWeavingConfiguration.class]]
25919 [RMI TCP Connection(3)-127.0.0.1] INFO org.springframework.context.weaving.DefaultContextLoadTimeWeaver - Determined server-specific load-time weaver: org.springframework.instrument.classloading.tomcat.TomcatLoadTimeWeaver
25920 [RMI TCP Connection(3)-127.0.0.1] WARN org.springframework.web.context.support.XmlWebApplicationContext - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.context.config.internalAspectJWeavingEnabler': Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'loadTimeWeaver' defined in class path resource [org/springframework/context/annotation/LoadTimeWeavingConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.instrument.classloading.LoadTimeWeaver]: Factory method 'loadTimeWeaver' threw exception; nested exception is java.lang.NullPointerException
25922 [RMI TCP Connection(3)-127.0.0.1] ERROR org.springframework.web.servlet.DispatcherServlet - Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.context.config.internalAspectJWeavingEnabler': Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'loadTimeWeaver' defined in class path resource [org/springframework/context/annotation/LoadTimeWeavingConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.instrument.classloading.LoadTimeWeaver]: Factory method 'loadTimeWeaver' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:562)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:166)
at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:686)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:524)
at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:668)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:634)
at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:682)
at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:553)
at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:494)
at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
at javax.servlet.GenericServlet.init(GenericServlet.java:158)
at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1269)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1182)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1072)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5368)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5660)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:899)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:875)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:652)
at org.apache.catalina.startup.HostConfig.manageApp(HostConfig.java:1863)
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.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:301)
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:618)
at org.apache.catalina.mbeans.MBeanFactory.createStandardContext(MBeanFactory.java:565)
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.apache.tomcat.util.modeler.BaseModelMBean.invoke(BaseModelMBean.java:301)
at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.invoke(DefaultMBeanServerInterceptor.java:819)
at com.sun.jmx.mbeanserver.JmxMBeanServer.invoke(JmxMBeanServer.java:801)
at javax.management.remote.rmi.RMIConnectionImpl.doOperation(RMIConnectionImpl.java:1468)
at javax.management.remote.rmi.RMIConnectionImpl.access$300(RMIConnectionImpl.java:76)
at javax.management.remote.rmi.RMIConnectionImpl$PrivilegedOperation.run(RMIConnectionImpl.java:1309)
at javax.management.remote.rmi.RMIConnectionImpl.doPrivilegedOperation(RMIConnectionImpl.java:1401)
at javax.management.remote.rmi.RMIConnectionImpl.invoke(RMIConnectionImpl.java:829)
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 sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:324)
at sun.rmi.transport.Transport$1.run(Transport.java:200)
at sun.rmi.transport.Transport$1.run(Transport.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:568)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:683)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'loadTimeWeaver' defined in class path resource [org/springframework/context/annotation/LoadTimeWeavingConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.instrument.classloading.LoadTimeWeaver]: Factory method 'loadTimeWeaver' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:599)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1128)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1022)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:512)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
at org.springframework.context.weaving.LoadTimeWeaverAwareProcessor.postProcessBeforeInitialization(LoadTimeWeaverAwareProcessor.java:97)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization(AbstractAutowireCapableBeanFactory.java:408)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1575)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
... 63 more
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.instrument.classloading.LoadTimeWeaver]: Factory method 'loadTimeWeaver' threw exception; nested exception is java.lang.NullPointerException
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189)
at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588)
... 75 more
Caused by: java.lang.NullPointerException
at org.springframework.context.annotation.LoadTimeWeavingConfiguration.loadTimeWeaver(LoadTimeWeavingConfiguration.java:87)
at org.springframework.context.annotation.LoadTimeWeavingConfiguration$$EnhancerBySpringCGLIB$$50f50148.CGLIB$loadTimeWeaver$1(<generated>)
at org.springframework.context.annotation.LoadTimeWeavingConfiguration$$EnhancerBySpringCGLIB$$50f50148$$FastClassBySpringCGLIB$$82132845.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:228)
at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:356)
at org.springframework.context.annotation.LoadTimeWeavingConfiguration$$EnhancerBySpringCGLIB$$50f50148.loadTimeWeaver(<generated>)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
{CODE}

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Affects: 4.3.4

Issue Links:

• Self-injection in configuration class hierarchies broken [SPR-10668] #15296 Self-injection in configuration class hierarchies broken
• ImportAware.setImportMetadata not invoked if import inherited from superclass with negative condition [SPR-14972] #19538 ImportAware.setImportMetadata not invoked if import inherited from superclass with negative condition
• Injecting bean in configurable class using load-time weaving broken when referenced on scoped-proxy class [SPR-14892] #19458 Injecting bean in configurable class using load-time weaving broken when referenced on scoped-proxy class
• Detect LoadTimeWeaver bean when declared through @Bean method as well [SPR-10856] #15483 Detect LoadTimeWeaver bean when declared through @Bean method as well

[spring-projects-issues]

Juergen Hoeller commented

Could it be that you're declaring <context:load-time-weaver> as well as @EnableLoadTimeWeaving? In such a combination, the former's standalone AspectJWeavingEnabler requests the LoadTimeWeaver in the BeanFactoryPostProcessor phase, where the latter's loadTimeWeaver() factory method isn't initialized yet since ImportAware processing happens one phase later.

In general, I recommend declaring either <context:load-time-weaver> or @EnableLoadTimeWeaving, not both. Each of those should work fine already.

That said, I've revised our arrangement there for 4.3.5, registering the ImportAwareBeanPostProcessor programmatically instead of as a type-detectable bean, also covering #15296's BeanFactoryAware use case the same way. This is generally more defensive and also makes unintended combinations like yours work reliably.