A reproducer for the JDK-8245951 JFR memory leak. The leak is jdk.jfr.internal.TypeLibrary keeps on holding to jdk.jfr.internal.PlatformEventType instances even when the underlying classes are unloaded.
This can for example happen when you redeploy a web application that contains custom JFR events.
The dominator tree shows the issue is jdk.jfr.internal.TypeLibrary.
The histogram shows the issue is jdk.jfr.internal.TypeLibrary holding on to jdk.jfr.internal.PlatformEventType.
The object list shows the issue is jdk.jfr.internal.TypeLibrary#types holding on to jdk.jfr.internal.PlatformEventType.
The classloader explorer shows not ClassLoader-leaks.
The issue can be reproduced with
java -Xmx64m -Xms64m -XX:MaxMetaspaceSize=64m -XX:+UseSerialGC -XX:+HeapDumpOnOutOfMemoryError -jar target/jfr-leaker-0.1.0-SNAPSHOT.jar