Is there way to find out what kind of object is sent from Deployer to ActiveMQ when publishing happens

Question

Do we have any way to find out what kind of object is sent from Deployer to ActiveMQ when publishing happens for any item like Page?

We have an existing Java MVC application which had ActiveMQ 5.10.0 with 2013 Deployer and now we are moved to Sites 9.1 Deployer and using ActiveMQ 5.15.9 version and when application listens to the response from ActiveMQ on publishing then it giving below error.

I'm trying to find out if there is a change in response when Deployer sends the message to ActiveMQ and I can find out that response:

Failed to build body from bytes. Reason: java.io.InvalidClassException: com.tridion.cache.CacheEvent; local class incompatible: stream classdesc serialVersionUID = 1252887747292650827, local class serialVersionUID = -8109545960597551825

Answer 1

The CacheEvent class has changed between 2013 and 9.1. I recommend that you recompile your custom code against the 9.1 libraries. You can either grab the jars from the API role, or get them from Maven by adding references to com.tridion.contentdelivery:udp-core and com.tridion.contentdelivery:udp-cache to your pom.

You may need to add one or two other libraries as well, to make it compile.