AEM Java agent is grayed out, error UnsupportedOperationException

Products

• CA Application Performance Management (APM / Wily / Introscope)
• DX Application Performance Management
• DX APM SaaS

Issue/Introduction

The AEM agent is grayed out , the Agent log shows disconnection after an UnsupportedOperationException:

[DEBUG] [IntroscopeAgent.IncomingMessageDeliveryTask] Unrecoverable exception while reading from Socket Transport connected with Socke
java.lang.UnsupportedOperationException: Deserialization not allowed for class com.wily.isengard.util.tree.InvalidPathException 
   at org.kantega.notsoserial.DefaultNotSoSerial.preventDeserialization(DefaultNotSoSerial.java:256)
   at org.kantega.notsoserial.DefaultNotSoSerial.onBeforeResolveClass(DefaultNotSoSerial.java:248

[VERBOSE] [IntroscopeAgent.PostOfficeHub] Disconnected From: 

Environment

• DX APM 10.*
• DX APM SaaS

Cause

The problem is due to notsoserial lib not allowing Deserialization of an APM class.

Resolution

Ensure that the APM class (com.wily.isengard.util.tree.InvalidPathException) was whitelisted in notsoserial config in AEM AppServer side.

See KB : Adobe AEM with JavaAgent enabled keeps disconnecting from the Enterprise Manager