Serialization does not work when deploying to Tomcat 8.0.21.

Tomcat has removed org.apache.catalina.ha.session.SerializablePrincipal, which MSM uses. Serialization fails with the following stack trace:

SEVERE [http-nio-8080-exec-5] org.apache.coyote.http11.AbstractHttp11Processor.process Error processing request java.lang.NoClassDefFoundError: org/apache/catalina/ha/session/SerializablePrincipal at de.javakaffee.web.msm.TranscoderService.serializePrincipal(TranscoderService.java:352) at de.javakaffee.web.msm.TranscoderService.serializeSessionFields(TranscoderService.java:207) at de.javakaffee.web.msm.TranscoderService.serializeSessionFields(TranscoderService.java:194) at de.javakaffee.web.msm.TranscoderService.serialize(TranscoderService.java:184) at de.javakaffee.web.msm.BackupSessionTask.call(BackupSessionTask.java:118) at de.javakaffee.web.msm.BackupSessionTask.call(BackupSessionTask.java:51) at de.javakaffee.web.msm.BackupSessionService$SynchronousExecutorService.submit(BackupSessionService.java:346) at de.javakaffee.web.msm.BackupSessionService.backupSession(BackupSessionService.java:205) at de.javakaffee.web.msm.MemcachedSessionService.backupSession(MemcachedSessionService.java:1040) at de.javakaffee.web.msm.RequestTrackingHostValve.backupSession(RequestTrackingHostValve.java:230) at de.javakaffee.web.msm.RequestTrackingHostValve.invoke(RequestTrackingHostValve.java:159) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668) at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1517) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1474) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:745) Caused by: java.lang.ClassNotFoundException: org.apache.catalina.ha.session.SerializablePrincipal at java.net.URLClassLoader$1.run(URLClassLoader.java:372) at java.net.URLClassLoader$1.run(URLClassLoader.java:361) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:360) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ... 24 more

The class was deleted on the 16:th of December 2014 according to this mailing list message: http://svn.apache.org/viewvc?view=revision&revision=1645955. It is likely that earlier versions of Tomcat also are affected, but I haven't tested that. According to the patch, it is no longer needed since "GenericPrincipal now implements Serializable".

This has been tested with on: Mac OS X 10.10.3 Oracle Java 1.8.0_11 Apache Tomcat 8.0.21 memcached-session-manager 1.8.3 memcached-session-manager-tc8 1.8.3

Issues are moved to github, this one is now https://github.com/magro/memcached-session-manager/issues/266