Java 16 shipped and with it JEP 387: Elastic Metaspace. JEP 387 was massive, my most extensive OpenJDK contribution so far.

With JDK 11, we added a new diagnostic command to jcmd: VM.metaspace.

This command is very useful to analyze Metaspace consumption. So, lets dive in and use this to revisit our Little WildFly Server That Could from previous articles. We describe the command output and options and how to use it to spot typical waste points.