APM Java Agent doesn't load when Dynatrace agent is also deployed on the application

Products

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

Issue/Introduction

The APM Java agent doesn't load on one of our applications. We tried to reinstall the agent but it still does not load. The agent is not seen in the APM UI and there are no logs generated in the AGENT_HOME/logs folder.

Environment

APM Java Agent 10.x

Cause

There is a clash between the Dynatrace and APM agents and if the Dynatrace agent is already loaded, the APM agent can not be initialized.
You can check if the Dynatrace agent is loaded by running:

lsof -p <pid of application>

Check the output for a line similar to the following:

java    23615  ins  mem       REG              253,0   2535041      9556 /opt/dynatrace/oneagent/agent/bin/1.195.148.20200707-160955/any/java/oneagentjava.jar

This indicates that the Dynatrace agent is already loaded.

Resolution

UnInstall the Dynatrace agent and restart the application and check that the APM java agent starts writing logs to AGENT_HOME/logs and is visible in the APM UI.