IMO, it seems to be a bug of the CDI implementation, as you said the method corresponding to the lambda body is synthetized so it should be ignored by the CDI implementation, no ? BTW, it's the wrong list, lambdas are delivered so you should have use core-lib-dev instead (in CC). cheers, Rémi ----- Mail original ----- De: "arjan tijms" <arjan.tijms@gmail.com> À: lambda-dev@openjdk.java.net Envoyé: Mercredi 26 Août 2015 16:04:22 Objet: U60 change makes annotations visible in synthesized methods, causes CDI to see lambdas as observer methods Hi, I'm with the JSF EG/Mojarra team and we're seeing what looks like a problematic regression in JDK8 u60. In a CDI extension we have the following observer method: public <T> void processBean(@Observes ProcessBean<T> event, BeanManager beanManager) { getAnnotation(beanManager, event.getAnnotated(), FacesDataModel.class) .ifPresent(d -> forClassToDataModelClass.put( d.forClass(), (Class<? extends DataModel<?>>) event.getBean().getBeanClass() ) ); } With u45 and below this will generate the following (decompiled the class with javap -v -p -s -c) private void lambda$processBean$4(javax.enterprise.inject.spi.ProcessBean, javax.faces.model.FacesDataModel); descriptor: (Ljavax/enterprise/inject/spi/ProcessBean;Ljavax/faces/model/FacesDataModel;)V flags: ACC_PRIVATE, ACC_SYNTHETIC Code: stack=3, locals=3, args_size=3 0: aload_0 1: getfield #4 // Field forClassToDataModelClass:Ljava/util/Map; 4: aload_2 5: invokeinterface #57, 1 // InterfaceMethod javax/faces/model/FacesDataModel.forClass:()Ljava/lang/Class; 10: aload_1 11: invokeinterface #58, 1 // InterfaceMethod javax/enterprise/inject/spi/ProcessBean.getBean:()Ljavax/enterprise/inject/spi/Bean; 16: invokeinterface #59, 1 // InterfaceMethod javax/enterprise/inject/spi/Bean.getBeanClass:()Ljava/lang/Class; 21: invokeinterface #55, 3 // InterfaceMethod java/util/Map.put:(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object; 26: checkcast #45 // class java/lang/Class 29: pop 30: return LineNumberTable: line 110: 0 line 111: 5 line 112: 11 line 110: 21 LocalVariableTable: Start Length Slot Name Signature 0 31 0 this Lcom/sun/faces/cdi/CdiExtension; 0 31 2 d Ljavax/faces/model/FacesDataModel; U60 however generates the following: private void lambda$processBean$4(javax.enterprise.inject.spi.ProcessBean, javax.faces.model.FacesDataModel); descriptor: (Ljavax/enterprise/inject/spi/ProcessBean;Ljavax/faces/model/FacesDataModel;)V flags: ACC_PRIVATE, ACC_SYNTHETIC Code: stack=3, locals=3, args_size=3 0: aload_0 1: getfield #4 // Field forClassToDataModelClass:Ljava/util/Map; 4: aload_2 5: invokeinterface #57, 1 // InterfaceMethod javax/faces/model/FacesDataModel.forClass:()Ljava/lang/Class; 10: aload_1 11: invokeinterface #58, 1 // InterfaceMethod javax/enterprise/inject/spi/ProcessBean.getBean:()Ljavax/enterprise/inject/spi/Bean; 16: invokeinterface #59, 1 // InterfaceMethod javax/enterprise/inject/spi/Bean.getBeanClass:()Ljava/lang/Class; 21: invokeinterface #55, 3 // InterfaceMethod java/util/Map.put:(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object; 26: checkcast #45 // class java/lang/Class 29: pop 30: return LineNumberTable: line 110: 0 line 111: 5 line 112: 11 line 110: 21 LocalVariableTable: Start Length Slot Name Signature 0 31 0 this Lcom/sun/faces/cdi/CdiExtension; 0 31 1 event Ljavax/enterprise/inject/spi/ProcessBean; 0 31 2 d Ljavax/faces/model/FacesDataModel; RuntimeVisibleParameterAnnotations: parameter 0: 0: #79() parameter 1: The difference is that the parameter annotation is made visible for this synthesized method. The result is that CDI subsequently scans this class and sees the synthesized method for the lambda as an observer method, which is of course not the intention. In this particular case it will result in a definition error: "Error occurred during deployment: Exception while loading the app : CDI definition failure: WELD-000409: Observer method for container lifecycle event [[BackedAnnotatedMethod] private com.sun.faces.cdi.CdiExtension.lambda$processBean$4(@Observes ProcessBean<Object>, FacesDataModel)] can only inject BeanManager.." I think that if the synthesized method happened to be a correct observer method, e.g. for a no-parameter lambda or one that happens to have the BeanManager as its first and only parameter, then CDI would silently start to call this method in response to events, which too is highly undesirable. Kind regards, Arjan Tijms