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https://issues.apache.org/jira/browse/JCS-240?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17785023#comment-17785023
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Greg Parmiter commented on JCS-240:
-----------------------------------
Sounds good - thanks [~tv]
> Remote cache appears incompatible with JDK 8u241 and above
> ----------------------------------------------------------
>
> Key: JCS-240
> URL: https://issues.apache.org/jira/browse/JCS-240
> Project: Commons JCS
> Issue Type: Bug
> Components: RMI Remote Cache
> Affects Versions: jcs-3.2
> Reporter: Greg Parmiter
> Assignee: Thomas Vandahl
> Priority: Critical
>
> After setting up remote RMI cache, with the central cache service running in
> the same app server/JVM (JDK version 11) as ~4 clients, there were
> intermittent put and remove failures, as well as issues similar to JCS-237,
> JCS-238, and JCS-239.
> While investigating the intermittent put/remove issues, the remote server log
> showed the following-
> {code:java}
> Error while running event from Queue: PutEvent for key: key1 value: null.
> Retrying...
> java.rmi.RemoteException: Method is not Remote: interface
> org.apache.commons.jcs3.engine.behavior.ICacheListener::public abstract void
> org.apache.commons.jcs3.engine.behavior.ICacheListener.handlePut(org.apache.commons.jcs3.engine.behavior.ICacheElement)
> throws java.io.IOException
> at
> java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:214)
> ~[?:?]
> at
> java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvocationHandler.java:162)
> ~[?:?]
> at com.sun.proxy.$Proxy2195.handlePut(Unknown Source) ~[?:?]
> at
> org.apache.commons.jcs3.engine.AbstractCacheEventQueue$PutEvent.doRun(AbstractCacheEventQueue.java:277)
> ~[commons-jcs3-core-3.2.jar:3.2]
> at
> org.apache.commons.jcs3.engine.AbstractCacheEventQueue$AbstractCacheEvent.run(AbstractCacheEventQueue.java:216)
> ~[commons-jcs3-core-3.2.jar:3.2]
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
> ~[?:?]
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
> ~[?:?]
> at java.lang.Thread.run(Thread.java:829) ~[?:?]{code}
> This pointed to an incorrect listener being registered from the client(s),
> but when debugging, I saw that the clients were registering the correct
> listener type, which implements the Remote interface-
> {code:java}
> listener =
> RemoteCacheListener:
> AbstractRemoteCacheListener:
> RemoteHost = localhost:1101
> ListenerId = 4 {code}
> I understand there's a class hierarchy in place where the RemoveCacheListener
> implements the IRemoteCacheListener interface, which is a sub-interface of
> Remote, but therein lies the issue. When the event queue is being processed
> at runtime and the ICacheListener is being proxied to the appropriate
> concrete class, the JVM does not recognize the sub-interface and thus, the
> Remote interface is not seen. *The appears to occur in JDK 11 JVMs but not
> JDK 8. In other words, JCS 3.2 remote cache does not appear to work properly
> in JDK 11 (and higher?) runtimes.*
> I "resolved" this by implementing the Remote interface in the ICacheListener,
> and this actually resolved JCS-237, JCS-238, and JCS-239. That said, it's
> likely not the optimal solution here. Another option-
> Create another abstract class, AbstractRemoteCacheEventQueue, that passes the
> IRemoteCacheListener rather than the base ICacheListener to the applicable
> listener. This would obviously have to be added into the appropriate place(s)
> in the hierarchy (i.e., RemoteCacheListener, etc.).
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