UIAttributes must be serializable

[gdressino]

I'm getting this error because com.github.appreciated.app.layout.session.UIAttributes is not serializable but that class access and stores an instance of it in the user session.

When using jetty, the session cannot be serialized because of this error:

	at org.eclipse.jetty.server.session.FileSessionDataStore.doStore(FileSessionDataStore.java:331)
	at org.eclipse.jetty.server.session.AbstractSessionDataStore$1.run(AbstractSessionDataStore.java:142)
	at org.eclipse.jetty.server.handler.ContextHandler.handle(ContextHandler.java:1382)
	at org.eclipse.jetty.server.handler.ContextHandler.handle(ContextHandler.java:1401)
	at org.eclipse.jetty.server.session.SessionContext.run(SessionContext.java:92)
	at org.eclipse.jetty.server.session.AbstractSessionDataStore.store(AbstractSessionDataStore.java:155)
	at org.eclipse.jetty.server.session.AbstractSessionCache.release(AbstractSessionCache.java:566)
	at org.eclipse.jetty.server.session.SessionHandler.complete(SessionHandler.java:368)
	at org.eclipse.jetty.server.Request.leaveSession(Request.java:399)
	at org.eclipse.jetty.server.Request.onCompleted(Request.java:1531)
	at org.eclipse.jetty.server.HttpChannel.onCompleted(HttpChannel.java:732)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:363)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:270)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:117)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:336)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:313)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:171)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:129)
	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:388)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:806)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:938)
	at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.io.NotSerializableException: com.github.appreciated.app.layout.session.UIAttributes
	at java.base/java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1185)
	at java.base/java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:349)
	at java.base/java.util.HashMap.internalWriteEntries(HashMap.java:1840)
	at java.base/java.util.HashMap.writeObject(HashMap.java:1411)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
	at java.base/java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1145)
	at java.base/java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1497)
	at java.base/java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1433)
	at java.base/java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1179)
	at java.base/java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1553)
	at java.base/java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1510)
	at java.base/java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1433)
	at java.base/java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1179)
	at java.base/java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1553)
	at java.base/java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1510)
	at java.base/java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1433)
	at java.base/java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1179)
	at java.base/java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:349)
	at org.eclipse.jetty.server.session.SessionData.serializeAttributes(SessionData.java:116)
	at org.eclipse.jetty.server.session.FileSessionDataStore.save(FileSessionDataStore.java:479)
	at org.eclipse.jetty.server.session.FileSessionDataStore.doStore(FileSessionDataStore.java:324)
	... 23 more

Remember that objects stored in HttpSession should be Serializable.

[kyberorg]

I will add that com.github.appreciated.app.layout.session.UIAttributes causes OutOfMemory exception in my app.