The Java Agent excludes system classes like java.lang.* from instrumentation by default. To enable instrumentation for a system class, use an agent configuration property.

Instrumented system classes add to the resource overhead introduced by the agent. The amount of overhead depends on the number of calls to the classes. AppDynamics recommends that you instrument a few nodes first and monitor the performance for these nodes before configuring all nodes in your system.

To instrument a Java system class:

  1. Open the <agent_home>/conf/app-agent-config.xml file for the node where you want to enable instrumentation.
  2. Add an <override-system-exclude> element with the fully qualified system class name to be instrumented in the <bci-processing-excludes> element. The  <override-system-exclude> element is used to allowlist classes (for example, 'com.sun.jersey') for instrumentation despite a blocklist ('com.sun.*'). 

    For example:

    <bci-processing-excludes>
<override-system-exclude filter-type="equals" filter-value="com.sun.jersey"/>
</bci-processing-excludes>
    CODE

    You can use these filter types:

    • equals
    • startswith
    • contains
  3. Restart the JVM for which you have modified the XML file. Once you restart the JVM, the package will be included in the instrumentation.