The StyleBean class is part of the Component Showcase common source code. It implements the Serializable interface since it is a session-scoped bean but it's inner class, StylePath, does not. This leads to:

Caused by: java.io.NotSerializableException: org.icefaces.application.showcase.util.StyleBean$StylePath
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1081)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:302)
at java.util.HashMap.writeObject(HashMap.java:1039)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:917)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1339)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079)
at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1375)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1347)
at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1290)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1079)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:302)
at org.apache.catalina.session.StandardSession.writeObject(StandardSession.java:1517)
at org.apache.catalina.session.StandardSession.writeObjectData(StandardSession.java:959)
at org.apache.catalina.session.StandardManager.doUnload(StandardManager.java:517)
at org.apache.catalina.session.StandardManager.unload(StandardManager.java:463)
at org.apache.catalina.session.StandardManager.stop(StandardManager.java:667)
at org.apache.catalina.core.StandardContext.stop(StandardContext.java:4519)
at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1108)
... 8 more

I only ran this on Tomcat 6. I'm not 100% sure why it started happening only recently although it may be related to our work around proper state-saving.