Persisting Vaadin/Spring Session: NotSerializableException

I am trying to persist my spring session in order to support a “remember me” functionality. I enabled the session storage with @EnableJdbcHttpSession, but some classes in my VaadinSession cannot be serialized:

org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.Object]
 to type [byte[]
] for value 'com.vaadin.flow.spring.SpringVaadinSession@63f777e5'; nested exception is org.springframework.core.serializer.support.SerializationFailedException: Failed to serialize object using DefaultSerializer; nested exception is java.io.NotSerializableException: com.vaadin.flow.internal.nodefeature.ElementListenerMap$DomEventListenerWrapper
	at org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:46) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	at org.springframework.core.convert.support.GenericConversionService.convert(GenericConversionService.java:191) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	at org.springframework.session.jdbc.JdbcOperationsSessionRepository.serialize(JdbcOperationsSessionRepository.java:627) ~[spring-session-1.3.3.RELEASE.jar:na]

	at org.springframework.session.jdbc.JdbcOperationsSessionRepository.access$400(JdbcOperationsSessionRepository.java:130) ~[spring-session-1.3.3.RELEASE.jar:na]

	at org.springframework.session.jdbc.JdbcOperationsSessionRepository$2$3.setValues(JdbcOperationsSessionRepository.java:456) ~[spring-session-1.3.3.RELEASE.jar:na]

	at org.springframework.jdbc.core.JdbcTemplate.lambda$update$0(JdbcTemplate.java:853) ~[spring-jdbc-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:605) ~[spring-jdbc-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:850) ~[spring-jdbc-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:905) ~[spring-jdbc-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	at org.springframework.session.jdbc.JdbcOperationsSessionRepository$2.doInTransactionWithoutResult(JdbcOperationsSessionRepository.java:451) ~[spring-session-1.3.3.RELEASE.jar:na]

	at org.springframework.transaction.support.TransactionCallbackWithoutResult.doInTransaction(TransactionCallbackWithoutResult.java:36) ~[spring-tx-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:140) ~[spring-tx-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	at org.springframework.session.jdbc.JdbcOperationsSessionRepository.save(JdbcOperationsSessionRepository.java:417) ~[spring-session-1.3.3.RELEASE.jar:na]

	at org.springframework.session.jdbc.JdbcOperationsSessionRepository.save(JdbcOperationsSessionRepository.java:130) ~[spring-session-1.3.3.RELEASE.jar:na]

	at org.springframework.session.web.http.SessionRepositoryFilter$SessionRepositoryRequestWrapper.commitSession(SessionRepositoryFilter.java:245) ~[spring-session-1.3.3.RELEASE.jar:na]

	at org.springframework.session.web.http.SessionRepositoryFilter$SessionRepositoryRequestWrapper.access$100(SessionRepositoryFilter.java:217) ~[spring-session-1.3.3.RELEASE.jar:na]

	at org.springframework.session.web.http.SessionRepositoryFilter.doFilterInternal(SessionRepositoryFilter.java:170) ~[spring-session-1.3.3.RELEASE.jar:na]

	at org.springframework.session.web.http.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:80) ~[spring-session-1.3.3.RELEASE.jar:na]

	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:728) ~[tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:472) ~[tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:395) ~[tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:316) ~[tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:395) [tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:254) [tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.catalina.core.StandardHostValve.throwable(StandardHostValve.java:349) [tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:175) [tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) [tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790) [tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) [tomcat-embed-core-8.5.28.jar:8.5.28]

	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.28.jar:8.5.28]

	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_121]

	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_121]

	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.28.jar:8.5.28]

	at java.lang.Thread.run(Thread.java:745) [na:1.8.0_121]

Caused by: org.springframework.core.serializer.support.SerializationFailedException: Failed to serialize object using DefaultSerializer; nested exception is java.io.NotSerializableException: com.vaadin.flow.internal.nodefeature.ElementListenerMap$DomEventListenerWrapper
	at org.springframework.core.serializer.support.SerializingConverter.convert(SerializingConverter.java:68) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	at org.springframework.core.serializer.support.SerializingConverter.convert(SerializingConverter.java:35) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	at org.springframework.core.convert.support.GenericConversionService$ConverterAdapter.convert(GenericConversionService.java:385) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	at org.springframework.core.convert.support.ConversionUtils.invokeConverter(ConversionUtils.java:40) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	... 39 common frames omitted
Caused by: java.io.NotSerializableException: com.vaadin.flow.internal.nodefeature.ElementListenerMap$DomEventListenerWrapper
	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1184) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[na:1.8.0_121]

	at java.util.ArrayList.writeObject(ArrayList.java:762) ~[na:1.8.0_121]

	at sun.reflect.GeneratedMethodAccessor54.invoke(Unknown Source) ~[na:na]

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]

	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

	at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028) ~[na:1.8.0_121]

Looks like a bug.
Though I don’t see which class in the exception is not serializable…
Could you please create a ticket?

If you run the server with -Dsun.io.serialization.extendedDebugInfo=true, you should get better info about what is not serializable

Here is the extended output:

Caused by: java.io.NotSerializableException: com.vaadin.flow.internal.nodefeature.ElementListenerMap$DomEventListenerWrapper
	- custom writeObject data (class "java.util.ArrayList")
	- object (class "java.util.ArrayList", [com.vaadin.flow.internal.nodefeature.ElementListenerMap$DomEventListenerWrapper@22ebe4b8]
)
	- custom writeObject data (class "java.util.HashMap")
	- object (class "java.util.HashMap", {autocomplete-selected=[com.vaadin.flow.internal.nodefeature.ElementListenerMap$DomEventListenerWrapper@22ebe4b8]
})
	- field (class "com.vaadin.flow.internal.nodefeature.ElementListenerMap", name: "listeners", type: "interface java.util.Map")
	- object (class "com.vaadin.flow.internal.nodefeature.ElementListenerMap", com.vaadin.flow.internal.nodefeature.ElementListenerMap@47398516)
	- custom writeObject data (class "java.util.HashMap")
	- object (class "java.util.HashMap", {class com.vaadin.flow.internal.nodefeature.ClientDelegateHandlers=com.vaadin.flow.internal.nodefeature.ClientDelegateHandlers@5dcabe04, class com.vaadin.flow.internal.nodefeature.ElementData=com.vaadin.flow.internal.nodefeature.ElementData@7e32b2e3, class com.vaadin.flow.internal.nodefeature.ElementClassList=com.vaadin.flow.internal.nodefeature.ElementClassList@7405768c, class com.vaadin.flow.internal.nodefeature.ElementListenerMap=com.vaadin.flow.internal.nodefeature.ElementListenerMap@47398516, class com.vaadin.flow.internal.nodefeature.SynchronizedPropertiesList=com.vaadin.flow.internal.nodefeature.SynchronizedPropertiesList@4f0b396b, class com.vaadin.flow.internal.nodefeature.ElementChildrenList=com.vaadin.flow.internal.nodefeature.ElementChildrenList@24452fc3, class com.vaadin.flow.internal.nodefeature.SynchronizedPropertyEventsList=com.vaadin.flow.internal.nodefeature.SynchronizedPropertyEventsList@7b2b8cd1, class com.vaadin.flow.internal.nodefeature.ElementPropertyMap=com.vaadin.flow.internal.nodefeature.ElementPropertyMap@7031b797, class com.vaadin.flow.internal.nodefeature.PolymerEventListenerMap=com.vaadin.flow.internal.nodefeature.PolymerEventListenerMap@6667089b, class com.vaadin.flow.internal.nodefeature.VirtualChildrenList=com.vaadin.flow.internal.nodefeature.VirtualChildrenList@6b5108a3, class com.vaadin.flow.internal.nodefeature.AttachExistingElementFeature=com.vaadin.flow.internal.nodefeature.AttachExistingElementFeature@4cbb4c1c, class com.vaadin.flow.internal.nodefeature.ElementAttributeMap=com.vaadin.flow.internal.nodefeature.ElementAttributeMap@314bd713, class com.vaadin.flow.internal.nodefeature.ShadowRootData=com.vaadin.flow.internal.nodefeature.ShadowRootData@6f363271, class com.vaadin.flow.internal.nodefeature.PolymerServerEventHandlers=com.vaadin.flow.internal.nodefeature.PolymerServerEventHandlers@cc12b24, class com.vaadin.flow.internal.nodefeature.ElementStylePropertyMap=com.vaadin.flow.internal.nodefeature.ElementStylePropertyMap@1a0c5d0c, class com.vaadin.flow.internal.nodefeature.ComponentMapping=com.vaadin.flow.internal.nodefeature.ComponentMapping@7510e211})
	- field (class "com.vaadin.flow.internal.StateNode", name: "features", type: "interface java.util.Map")
	- object (class "com.vaadin.flow.internal.StateNode", com.vaadin.flow.internal.StateNode@3fac6def)
	- custom writeObject data (class "java.util.ArrayList")
	- object (class "java.util.ArrayList", [com.vaadin.flow.internal.StateNode@6b9daf5a, com.vaadin.flow.internal.StateNode@3fac6def]
)
	- field (class "com.vaadin.flow.internal.nodefeature.NodeList", name: "values", type: "interface java.util.List")
	- object (class "com.vaadin.flow.internal.nodefeature.ElementChildrenList", com.vaadin.flow.internal.nodefeature.ElementChildrenList@6512ae12)
	- custom writeObject data (class "java.util.HashMap")
	- object (class "java.util.HashMap", {class com.vaadin.flow.internal.nodefeature.ClientDelegateHandlers=com.vaadin.flow.internal.nodefeature.ClientDelegateHandlers@5eb20f91, class com.vaadin.flow.internal.nodefeature.ElementData=com.vaadin.flow.internal.nodefeature.ElementData@566a126e, class com.vaadin.flow.internal.nodefeature.ElementClassList=com.vaadin.flow.internal.nodefeature.ElementClassList@2632bdea, class com.vaadin.flow.internal.nodefeature.ElementListenerMap=com.vaadin.flow.internal.nodefeature.ElementListenerMap@2d6d65c8, class com.vaadin.flow.internal.nodefeature.SynchronizedPropertiesList=com.vaadin.flow.internal.nodefeature.SynchronizedPropertiesList@636d2973, class com.vaadin.flow.internal.nodefeature.ElementChildrenList=com.vaadin.flow.internal.nodefeature.ElementChildrenList@6512ae12, class com.vaadin.flow.internal.nodefeature.SynchronizedPropertyEventsList=com.vaadin.flow.internal.nodefeature.SynchronizedPropertyEventsList@56fc92b7, class com.vaadin.flow.internal.nodefeature.ElementPropertyMap=com.vaadin.flow.internal.nodefeature.ElementPropertyMap@10f9fe85, class com.vaadin.flow.internal.nodefeature.PolymerEventListenerMap=com.vaadin.flow.internal.nodefeature.PolymerEventListenerMap@1a556b58, class com.vaadin.flow.internal.nodefeature.VirtualChildrenList=com.vaadin.flow.internal.nodefeature.VirtualChildrenList@6ac7243e, class com.vaadin.flow.internal.nodefeature.AttachExistingElementFeature=com.vaadin.flow.internal.nodefeature.AttachExistingElementFeature@581c6afb, class com.vaadin.flow.internal.nodefeature.ElementAttributeMap=com.vaadin.flow.internal.nodefeature.ElementAttributeMap@7ceaaab, class com.vaadin.flow.internal.nodefeature.ShadowRootData=com.vaadin.flow.internal.nodefeature.ShadowRootData@36f00ea1, class com.vaadin.flow.internal.nodefeature.PolymerServerEventHandlers=com.vaadin.flow.internal.nodefeature.PolymerServerEventHandlers@65453a95, class com.vaadin.flow.internal.nodefeature.ElementStylePropertyMap=com.vaadin.flow.internal.nodefeature.ElementStylePropertyMap@5e35cf74, class com.vaadin.flow.internal.nodefeature.ComponentMapping=com.vaadin.flow.internal.nodefeature.ComponentMapping@2cdcadeb})
	- field (class "com.vaadin.flow.internal.StateNode", name: "features", type: "interface java.util.Map")
	- object (class "com.vaadin.flow.internal.StateNode", com.vaadin.flow.internal.StateNode@3647dd1b)
	- custom writeObject data (class "java.util.ArrayList")
	- object (class "java.util.ArrayList", [com.vaadin.flow.internal.StateNode@3647dd1b, com.vaadin.flow.internal.StateNode@67dc30a2, com.vaadin.flow.internal.StateNode@53d7decd, com.vaadin.flow.internal.StateNode@3d4e19f2]
)
	- field (class "com.vaadin.flow.internal.nodefeature.NodeList", name: "values", type: "interface java.util.List")
	- object (class "com.vaadin.flow.internal.nodefeature.ElementChildrenList", com.vaadin.flow.internal.nodefeature.ElementChildrenList@1fc11be2)
	- custom writeObject data (class "java.util.HashMap")
	- object (class "java.util.HashMap", {class com.vaadin.flow.internal.nodefeature.ClientDelegateHandlers=com.vaadin.flow.internal.nodefeature.ClientDelegateHandlers@27300802, class com.vaadin.flow.internal.nodefeature.ElementData=com.vaadin.flow.internal.nodefeature.ElementData@6ea09e3, class com.vaadin.flow.internal.nodefeature.ElementClassList=com.vaadin.flow.internal.nodefeature.ElementClassList@7b5a6ea2, class com.vaadin.flow.internal.nodefeature.ElementListenerMap=com.vaadin.flow.internal.nodefeature.ElementListenerMap@6e65c3e0, class com.vaadin.flow.internal.nodefeature.SynchronizedPropertiesList=com.vaadin.flow.internal.nodefeature.SynchronizedPropertiesList@4932b636, class com.vaadin.flow.internal.nodefeature.ElementChildrenList=com.vaadin.flow.internal.nodefeature.ElementChildrenList@1fc11be2, class com.vaadin.flow.internal.nodefeature.SynchronizedPropertyEventsList=com.vaadin.flow.internal.nodefeature.SynchronizedPropertyEventsList@37c659c6, class com.vaadin.flow.internal.nodefeature.ElementPropertyMap=com.vaadin.flow.internal.nodefeature.ElementPropertyMap@777cf61d, class com.vaadin.flow.internal.nodefeature.PolymerEventListenerMap=com.vaadin.flow.internal.nodefeature.PolymerEventListenerMap@2ba37dc2, class com.vaadin.flow.internal.nodefeature.VirtualChildrenList=com.vaadin.flow.internal.nodefeature.VirtualChildrenList@3c2a6d5f, class com.vaadin.flow.internal.nodefeature.AttachExistingElementFeature=com.vaadin.flow.internal.nodefeature.AttachExistingElementFeature@39a71b75, class com.vaadin.flow.internal.nodefeature.ElementAttributeMap=com.vaadin.flow.internal.nodefeature.ElementAttributeMap@29fbce42, class com.vaadin.flow.internal.nodefeature.ShadowRootData=com.vaadin.flow.internal.nodefeature.ShadowRootData@1986fbd2, class com.vaadin.flow.internal.nodefeature.PolymerServerEventHandlers=com.vaadin.flow.internal.nodefeature.PolymerServerEventHandlers@76293d28, class com.vaadin.flow.internal.nodefeature.ElementStylePropertyMap=com.vaadin.flow.internal.nodefeature.ElementStylePropertyMap@7754fc2b, class com.vaadin.flow.internal.nodefeature.ComponentMapping=com.vaadin.flow.internal.nodefeature.ComponentMapping@aaa55d})
	- field (class "com.vaadin.flow.internal.StateNode", name: "features", type: "interface java.util.Map")
	- object (class "com.vaadin.flow.internal.StateNode", com.vaadin.flow.internal.StateNode@480b76b6)
	- field (class "com.vaadin.flow.internal.StateNode", name: "parent", type: "class com.vaadin.flow.internal.StateNode")
	- object (class "com.vaadin.flow.internal.StateNode", com.vaadin.flow.internal.StateNode@3d4e19f2)
	- field (class "com.vaadin.flow.internal.StateNode", name: "parent", type: "class com.vaadin.flow.internal.StateNode")
	- object (class "com.vaadin.flow.internal.StateNode", com.vaadin.flow.internal.StateNode@48062dba)
	- field (class "com.vaadin.flow.internal.StateNode", name: "parent", type: "class com.vaadin.flow.internal.StateNode")
	- object (class "com.vaadin.flow.internal.StateNode", com.vaadin.flow.internal.StateNode@74d6a98a)
	- field (class "com.vaadin.flow.internal.StateNode", name: "parent", type: "class com.vaadin.flow.internal.StateNode")
	- object (class "com.vaadin.flow.internal.StateNode", com.vaadin.flow.internal.StateNode@4cde165c)
	- field (class "com.vaadin.flow.internal.StateNode", name: "parent", type: "class com.vaadin.flow.internal.StateNode")
	- object (class "com.vaadin.flow.internal.StateNode", com.vaadin.flow.internal.StateNode@6f4aef0d)
	- custom writeObject data (class "java.util.HashSet")
	- object (class "java.util.LinkedHashSet", [com.vaadin.flow.internal.StateNode@6f4aef0d, com.vaadin.flow.internal.StateNode@4cde165c, com.vaadin.flow.internal.StateNode@f3f4048, com.vaadin.flow.internal.StateNode@4c5c158b, com.vaadin.flow.internal.StateNode@74d6a98a, com.vaadin.flow.internal.StateNode@48062dba, com.vaadin.flow.internal.StateNode@1112a39d, com.vaadin.flow.internal.StateNode@50c9d2cc, com.vaadin.flow.internal.StateNode@641743d2, com.vaadin.flow.internal.StateNode@601d1a86, com.vaadin.flow.internal.StateNode@7edcebfb, com.vaadin.flow.internal.StateNode@d80057c, com.vaadin.flow.internal.StateNode@5b16371b, com.vaadin.flow.internal.StateNode@420c8cb1, com.vaadin.flow.internal.StateNode@4faada69, com.vaadin.flow.internal.StateNode@226654e7, com.vaadin.flow.internal.StateNode@4822115f, com.vaadin.flow.internal.StateNode@6eed65ee, com.vaadin.flow.internal.StateNode@770d83c8]
)
	- field (class "com.vaadin.flow.internal.StateTree", name: "dirtyNodes", type: "interface java.util.Set")
	- object (class "com.vaadin.flow.internal.StateTree", com.vaadin.flow.internal.StateTree@66c2bc90)
	- field (class "com.vaadin.flow.internal.StateNode", name: "owner", type: "interface com.vaadin.flow.internal.NodeOwner")
	- object (class "com.vaadin.flow.internal.StateNode", com.vaadin.flow.internal.StateNode@7dc817ef)
	- custom writeObject data (class "java.util.HashMap")
	- object (class "java.util.HashMap", {pushUrl=/vaadinServlet/, alwaysXhrToServer=true, pushMode=DISABLED, parameters=com.vaadin.flow.internal.StateNode@7dc817ef})
	- field (class "com.vaadin.flow.internal.nodefeature.NodeMap", name: "values", type: "interface java.util.Map")
	- object (class "com.vaadin.flow.internal.nodefeature.PushConfigurationMap", com.vaadin.flow.internal.nodefeature.PushConfigurationMap@7acb6303)
	- custom writeObject data (class "java.util.HashMap")
	- object (class "java.util.HashMap", {class com.vaadin.flow.internal.nodefeature.ClientDelegateHandlers=com.vaadin.flow.internal.nodefeature.ClientDelegateHandlers@35d33e94, class com.vaadin.flow.internal.nodefeature.ElementData=com.vaadin.flow.internal.nodefeature.ElementData@417afa5b, class com.vaadin.flow.internal.nodefeature.ElementClassList=com.vaadin.flow.internal.nodefeature.ElementClassList@4d8d4220, class com.vaadin.flow.internal.nodefeature.LoadingIndicatorConfigurationMap=com.vaadin.flow.internal.nodefeature.LoadingIndicatorConfigurationMap@67c5803d, class com.vaadin.flow.internal.nodefeature.ElementListenerMap=com.vaadin.flow.internal.nodefeature.ElementListenerMap@4b4e35cf, class com.vaadin.flow.internal.nodefeature.SynchronizedPropertiesList=com.vaadin.flow.internal.nodefeature.SynchronizedPropertiesList@5df0a6df, class com.vaadin.flow.internal.nodefeature.PushConfigurationMap=com.vaadin.flow.internal.nodefeature.PushConfigurationMap@7acb6303, class com.vaadin.flow.internal.nodefeature.ElementChildrenList=com.vaadin.flow.internal.nodefeature.ElementChildrenList@3144c00f, class com.vaadin.flow.internal.nodefeature.ReconnectDialogConfigurationMap=com.vaadin.flow.internal.nodefeature.ReconnectDialogConfigurationMap@b1e6ba5, class com.vaadin.flow.internal.nodefeature.SynchronizedPropertyEventsList=com.vaadin.flow.internal.nodefeature.SynchronizedPropertyEventsList@5380e247, class com.vaadin.flow.internal.nodefeature.ElementPropertyMap=com.vaadin.flow.internal.nodefeature.ElementPropertyMap@7272504f, class com.vaadin.flow.internal.nodefeature.PolymerEventListenerMap=com.vaadin.flow.internal.nodefeature.PolymerEventListenerMap@6521b2b6, class com.vaadin.flow.internal.nodefeature.VirtualChildrenList=com.vaadin.flow.internal.nodefeature.VirtualChildrenList@1d1aaef4, class com.vaadin.flow.internal.nodefeature.AttachExistingElementFeature=com.vaadin.flow.internal.nodefeature.AttachExistingElementFeature@495cf5ca, class com.vaadin.flow.internal.nodefeature.PollConfigurationMap=com.vaadin.flow.internal.nodefeature.PollConfigurationMap@29cc2486, class com.vaadin.flow.internal.nodefeature.ElementAttributeMap=com.vaadin.flow.internal.nodefeature.ElementAttributeMap@4190970b, class com.vaadin.flow.internal.nodefeature.ShadowRootData=com.vaadin.flow.internal.nodefeature.ShadowRootData@9b5ecc3, class com.vaadin.flow.internal.nodefeature.PolymerServerEventHandlers=com.vaadin.flow.internal.nodefeature.PolymerServerEventHandlers@27e9aa9a, class com.vaadin.flow.internal.nodefeature.ElementStylePropertyMap=com.vaadin.flow.internal.nodefeature.ElementStylePropertyMap@6f4952f5, class com.vaadin.flow.internal.nodefeature.ComponentMapping=com.vaadin.flow.internal.nodefeature.ComponentMapping@2a24b8d8})
	- field (class "com.vaadin.flow.internal.StateNode", name: "features", type: "interface java.util.Map")
	- object (class "com.vaadin.flow.internal.StateTree$RootNode", com.vaadin.flow.internal.StateTree$RootNode@4b192f42)
	- field (class "com.vaadin.flow.dom.Node", name: "node", type: "class com.vaadin.flow.internal.StateNode")
	- object (class "com.vaadin.flow.dom.Element", <body class="v-generated-body">
 <div theme="dark" style="flex-direction:column;display:flex;width:100%;height:100%">
  <nav class="menu">
   <span class="menu__title">ClausFit</span>
   <a router-link href="login" class="menu__link">Login</a>
  </nav>
  <div id="content" class="content">
   <div class="exercise-reference-table-view">
    <vaadin-horizontal-layout theme="spacing" class="exercise-step">
     <div class="exercise-step__prefix-wrapper">
      <div class="exercise-step__prefix">
       <span class="exercise-step__number">1</span>
       <span>Übungen auswählen</span>
      </div>
     </div>
     <paper-autocomplete-wrapper min-length="3" class="exercise-controls__autocomplete"></paper-autocomplete-wrapper>
    </vaadin-horizontal-layout>
    <vaadin-horizontal-layout theme="spacing" class="exercise-step">
     <div class="exercise-step__prefix-wrapper">
      <div class="exercise-step__prefix">
       <span class="exercise-step__number">2</span>
       <span>Reihenfolge anpassen</span>
      </div>
     </div>
     <div class="exercise-reference-table exercise-step__step"></div>
    </vaadin-horizontal-layout>
    <vaadin-horizontal-layout theme="spacing" class="exercise-step">
     <div class="exercise-step__prefix-wrapper">
      <div class="exercise-step__prefix">
       <span class="exercise-step__number">3</span>
       <vaadin-button class="exercise-controls__generate">
        Trainingsplan generieren
       </vaadin-button>
      </div>
     </div>
    </vaadin-horizontal-layout>
    <vaadin-horizontal-layout theme="spacing" class="exercise-step">
     <div class="exercise-step__prefix-wrapper">
      <div class="exercise-step__prefix">
       <span class="exercise-step__number">4</span>
       <a>Trainingsplan herunterladen</a>
      </div>
     </div>
    </vaadin-horizontal-layout>
   </div>
  </div>
 </div>
</body>)
	- field (class "com.vaadin.flow.component.Component", name: "element", type: "class com.vaadin.flow.dom.Element")
	- object (class "com.vaadin.flow.component.UI", com.vaadin.flow.component.UI@59e814c)
	- custom writeObject data (class "java.util.HashMap")
	- object (class "java.util.HashMap", {0=com.vaadin.flow.component.UI@59e814c})
	- field (class "com.vaadin.flow.server.VaadinSession", name: "uIs", type: "interface java.util.Map")
	- root object (class "com.vaadin.flow.spring.SpringVaadinSession", com.vaadin.flow.spring.SpringVaadinSession@593a86a8)
	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1182) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[na:1.8.0_121]

	at java.util.ArrayList.writeObject(ArrayList.java:762) ~[na:1.8.0_121]

	at sun.reflect.GeneratedMethodAccessor47.invoke(Unknown Source) ~[na:na]

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]

	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

	at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[na:1.8.0_121]

	at java.util.HashMap.internalWriteEntries(HashMap.java:1785) ~[na:1.8.0_121]

	at java.util.HashMap.writeObject(HashMap.java:1362) ~[na:1.8.0_121]

	at sun.reflect.GeneratedMethodAccessor46.invoke(Unknown Source) ~[na:na]

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]

	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

	at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[na:1.8.0_121]

	at java.util.HashMap.internalWriteEntries(HashMap.java:1785) ~[na:1.8.0_121]

	at java.util.HashMap.writeObject(HashMap.java:1362) ~[na:1.8.0_121]

	at sun.reflect.GeneratedMethodAccessor46.invoke(Unknown Source) ~[na:na]

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]

	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

	at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[na:1.8.0_121]

	at java.util.ArrayList.writeObject(ArrayList.java:762) ~[na:1.8.0_121]

	at sun.reflect.GeneratedMethodAccessor47.invoke(Unknown Source) ~[na:na]

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]

	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

	at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[na:1.8.0_121]

	at java.util.HashMap.internalWriteEntries(HashMap.java:1785) ~[na:1.8.0_121]

	at java.util.HashMap.writeObject(HashMap.java:1362) ~[na:1.8.0_121]

	at sun.reflect.GeneratedMethodAccessor46.invoke(Unknown Source) ~[na:na]

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]

	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

	at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[na:1.8.0_121]

	at java.util.ArrayList.writeObject(ArrayList.java:762) ~[na:1.8.0_121]

	at sun.reflect.GeneratedMethodAccessor47.invoke(Unknown Source) ~[na:na]

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]

	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

	at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[na:1.8.0_121]

	at java.util.HashMap.internalWriteEntries(HashMap.java:1785) ~[na:1.8.0_121]

	at java.util.HashMap.writeObject(HashMap.java:1362) ~[na:1.8.0_121]

	at sun.reflect.GeneratedMethodAccessor46.invoke(Unknown Source) ~[na:na]

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]

	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

	at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[na:1.8.0_121]

	at java.util.HashSet.writeObject(HashSet.java:287) ~[na:1.8.0_121]

	at sun.reflect.GeneratedMethodAccessor48.invoke(Unknown Source) ~[na:na]

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]

	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

	at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[na:1.8.0_121]

	at java.util.HashMap.internalWriteEntries(HashMap.java:1785) ~[na:1.8.0_121]

	at java.util.HashMap.writeObject(HashMap.java:1362) ~[na:1.8.0_121]

	at sun.reflect.GeneratedMethodAccessor46.invoke(Unknown Source) ~[na:na]

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]

	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

	at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[na:1.8.0_121]

	at java.util.HashMap.internalWriteEntries(HashMap.java:1785) ~[na:1.8.0_121]

	at java.util.HashMap.writeObject(HashMap.java:1362) ~[na:1.8.0_121]

	at sun.reflect.GeneratedMethodAccessor46.invoke(Unknown Source) ~[na:na]

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]

	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

	at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[na:1.8.0_121]

	at java.util.HashMap.internalWriteEntries(HashMap.java:1785) ~[na:1.8.0_121]

	at java.util.HashMap.writeObject(HashMap.java:1362) ~[na:1.8.0_121]

	at sun.reflect.GeneratedMethodAccessor46.invoke(Unknown Source) ~[na:na]

	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_121]

	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_121]

	at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178) ~[na:1.8.0_121]

	at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348) ~[na:1.8.0_121]

	at org.springframework.core.serializer.DefaultSerializer.serialize(DefaultSerializer.java:46) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	at org.springframework.core.serializer.support.SerializingConverter.convert(SerializingConverter.java:63) ~[spring-core-5.0.4.RELEASE.jar:5.0.4.RELEASE]

	... 42 common frames omitted

Where can I create a ticket?

https://github.com/vaadin/flow/issues

Done: https://github.com/vaadin/flow/issues/4105