$ jcmd 5287 JFR.start name=demo settings=profile maxsize=256m
5287:
Started recording 15.

Use jcmd 5287 JFR.dump name=demo filename=FILEPATH to copy recording data to file.

$ curl -s localhost:8080/api/jfr/recordings
[{"id":15,"name":"demo","state":"RUNNING","startTime":"2026-10-01T04:30:41.255843977Z","maxSize":268435456,"maxAge":"null","destination":"null"}]

$ jcmd 5287 JFR.stop name=demo filename=/tmp/throwaway-demo.jfr
5287:
Stopped recording "demo", 251.6 kB written to:

/tmp/throwaway-demo.jfr