Serialization exception when using Container Managed Security (Tomcat Realms)

[noctarius]

Environment:
Tomcat 8.0.20
hazelcast-all-3.6.4
hazelcast-tomcat8-sessionmanager-1.0
with „Container Managed Security” (Apache Tomcat Realm)

Caused by: java.io.NotSerializableException: org.apache.catalina.authenticator.SavedRequest
      at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1184)
      at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)
      at java.util.Hashtable.writeObject(Hashtable.java:1157)
      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 java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1028)
      at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496)
      at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)
      at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)
      at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)
      at com.hazelcast.internal.serialization.impl.JavaDefaultSerializers$JavaSerializer.write(JavaDefaultSerializers.java:242)
      at com.hazelcast.internal.serialization.impl.StreamSerializerAdapter.write(StreamSerializerAdapter.java:41)
      at com.hazelcast.internal.serialization.impl.AbstractSerializationService.writeObject(AbstractSerializationService.java:197)
      ... 49 more