Clustering error java.io.NotSerializableException: java.lang.ref.WeakReference

[former_member1027716]

After Rolling update (session replication) configuration faced out with errors during session replication. There were plenty of errors in the console. Half of them were fixed by adding Serializable + UID for classes. But still, the console has errors (see below).

The main Issue is

INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 | java.io.NotSerializableException: java.lang.ref.WeakReference

| jvm 1    | main    | 2020/03/04 09:46:21.348 |   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.348 |     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.348 |     at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.348 |     at java.lang.Thread.run(Thread.java:748)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.348 | 
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 | Mar 04, 2020 9:46:21 AM org.apache.catalina.ha.session.DeltaManager requestCompleted


START HERE

INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 | SEVERE: Unable to serialize delta request for sessionid [4DAA80172E8AA1BC6479A2C057D5AFB4]
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 | java.io.NotSerializableException: java.lang.ref.WeakReference
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1184)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.util.ArrayList.writeObject(ArrayList.java:766)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at sun.reflect.GeneratedMethodAccessor403.invoke(Unknown Source)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.lang.reflect.Method.invoke(Method.java:498)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1140)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.catalina.ha.session.DeltaRequest$AttributeInfo.writeExternal(DeltaRequest.java:407)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.catalina.ha.session.DeltaRequest.writeExternal(DeltaRequest.java:300)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.catalina.ha.session.DeltaRequest.serialize(DeltaRequest.java:314)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.catalina.ha.session.DeltaManager.serializeDeltaRequest(DeltaManager.java:584)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.catalina.ha.session.DeltaManager.requestCompleted(DeltaManager.java:967)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.catalina.ha.session.DeltaManager.requestCompleted(DeltaManager.java:935)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.catalina.ha.tcp.ReplicationValve.send(ReplicationValve.java:537)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.catalina.ha.tcp.ReplicationValve.sendMessage(ReplicationValve.java:524)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.catalina.ha.tcp.ReplicationValve.sendSessionReplicationMessage(ReplicationValve.java:506)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.catalina.ha.tcp.ReplicationValve.sendReplicationMessage(ReplicationValve.java:419)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.catalina.ha.tcp.ReplicationValve.invoke(ReplicationValve.java:343)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:1025)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1136)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:318)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
INFO   | jvm 1    | main    | 2020/03/04 09:46:21.548 |     at java.lang.Thread.run(Thread.java:748)

openjdk version "1.8.0_242"
OpenJDK Runtime Environment (build 1.8.0_242-b08)
OpenJDK 64-Bit Server VM (build 25.242-b08, mixed mode)

[Former Member]

java.io.NotSerializableException can occur when you serialize an inner class instance because serializing such an inner class instance will result in serialization of its associated outer class instance as well.

How to solve it?

• If the class is yours, make the class serializable by implementing the interface java.io.Serializable.
• All non primitive members implement Serializable (or are transient instead)
• If your class is an inner class it's either static or the outer class implements Serializable
• If the class is 3rd party, but you don't need it in the serialized form, mark the field as transient

It is important to note that Serialization of inner classes (i.e., nested classes that are not static member classes), including local and anonymous classes, is strongly discouraged.