In the previous post I have introduced the prototype of JFR support in BTrace.
The first attempt, however, was riddled with serious shortcomings - the events had to be defined externally and then added to boot classpath.
In addition to that the BTrace verifier had to be made more permeable to allow calls to JFR APIs - this caused the verifier complexity to increase significantly, opening potential holes to be exploited.
Fortunately, there is a very cool API directly in JDK which allows creating JFR event types dynamically, therefore removing the requirement to have the events defined beforehand and added to boot classpath. As an added benefit the refactoring allowed the use of the standard BTraceUtils accessor class for operating on JFR events, thus removing all the custom 'holes' in the BTrace verifier.
The implementation is available on GitHub in jfr_events branch. It is fairly complete (at least for the use cases I was able to come up with) but as usual a user input is more than welcome.
The code example showing the intended usage follows.
