The following test failed in the JDK20 CI:

runtime/ClassUnload/KeepAliveObject.java

in a test run with UsageTracker enabled.

Here's a log file snippet:

----------System.out:(3/81)----------
testObject (1) alive: true
testObject (2) alive: true
testObject (3) alive: true
----------System.err:(12/818)----------
jdk.test.lib.classloader.ClassUnloadCommon$TestFailure: Test failed: should be unloaded
at jdk.test.lib.classloader.ClassUnloadCommon.failIf(ClassUnloadCommon.java:51)
at KeepAliveObject.main(KeepAliveObject.java:76)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:578)
at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:125)
at java.base/java.lang.Thread.run(Thread.java:1591)

JavaTest Message: Test threw exception: jdk.test.lib.classloader.ClassUnloadCommon$TestFailure: Test failed: should be unloaded
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: jdk.test.lib.classloader.ClassUnloadCommon$TestFailure: Test failed: should be unloaded
----------rerun:(41/9561)*----------

This failure is an exact match for the following closed bug:

JDK-8044667 runtime/ClassUnload/KeepAliveObject.java: Test failed: should be unloaded

However, I'm not reopening that bug because this test failure
happened with UsageTracker involved and that may be a factor.