One of the not so well-known tools of the HotSpot VM is its Whitebox-Testing API. Introduced in Java 7 it has been significantly improved and extended in Java 8 and 9. It can be used to query or change HotSpot internals which are not otherwise exposed to Java-land. While its features make it an indispensable tool for writing good HotSpot regression tests, it can also be used for experiments or for the mere fun of peeking into the VM.

This talk will give an overview of the Whitebox-Testing API, it will show you how to build and use it and finally it will explain how the API can be easily extend to fit your own needs.