ClassCastException when Hot Deploy Application JARs
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ClassCastException when Hot Deploy Application JARs

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Article ID: 294142

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Updated On:

Products

VMware Tanzu Gemfire

Issue/Introduction

Symptoms:

This document contains a solution for the hot deployment of application JARs with a PDX serialized domain class to avoid a possible ClassCastException exception.

When hot deploying application JARs such as a PDX serialized domain class, the Gemfire server log may indicate the following exception:

[warning 2015/03/11 10:54:15.343 CST server-1 <ServerConnection on port 7901 Thread 45> tid=0xd2] Exception on server while executing function: TestCastFunction
com.gemstone.gemfire.cache.execute.FunctionException: java.lang.ClassCastException: customer.DataObjectClass cannot be cast to customer.DataObjectClass
at com.gemstone.gemfire.internal.cache.tier.sockets.command.ExecuteFunction66.cmdExecute(ExecuteFunction66.java:275)
at com.gemstone.gemfire.internal.cache.tier.sockets.command.ExecuteFunction70.cmdExecute(ExecuteFunction70.java:51)
at com.gemstone.gemfire.internal.cache.tier.sockets.BaseCommand.execute(BaseCommand.java:174)
at com.gemstone.gemfire.internal.cache.tier.sockets.ServerConnection.doNormalMsg(ServerConnection.java:809)
at com.gemstone.gemfire.internal.cache.tier.sockets.ServerConnection.doOneMessage(ServerConnection.java:940)
at com.gemstone.gemfire.internal.cache.tier.sockets.ServerConnection.run(ServerConnection.java:1153)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at com.gemstone.gemfire.internal.cache.tier.sockets.AcceptorImpl$1$1.run(AcceptorImpl.java:532)
at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.ClassCastException: customer.DataObjectClass cannot be cast to customer.DataObjectClass
at function.TestCastFunction.execute(TestCastFunction.java:54)
at com.gemstone.gemfire.internal.cache.tier.sockets.command.ExecuteFunction66.executeFunctionaLocally(ExecuteFunction66.java:331)
at com.gemstone.gemfire.internal.cache.tier.sockets.command.ExecuteFunction66.cmdExecute(ExecuteFunction66.java:261)
... 9 more

Environment


Cause

When deploying a new version of a PDX serialized domain class into a GemFire cluster while there is an operation, such as get from a client, the GemFire server will try to deserialize the PDX serialized object which is serialized by the previous version of domain class into the domain class form using the current new version of domain class. This will result in the above ClassCastException.

Resolution

Presently, GemFire's hot deployment of application JARs is mainly targeted at function service execution classes and not PDX serialized domain class.

To work around this issue, you can set the attribute read-serialized to true on the <pdx> element in the cache.xml file on the server side. This will cause the GemFire server to return a PdxInstance to client when a PDX serialized object is deserialized instead of deserializing the object to a domain class.

On the client side, you can create PdxInstances using a PdxInstanceFactory(Document Reference).

For example:

// Cache configuration setting PDX read behavior 
<cache>
<pdx read-serialized="true" />
...
</cache>



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