- Get the full list of the available jcmd commands by running the following line:
jcmd PID/main-class-name help
Instead of PID/main-class, put the process identifier or the main class name. The list is specific to the JVM, so the command requests the data from the specific process.
- If you can, compile the same class with JDK 8 and with JDK 9 and run the preceding command for each of the JSK versions. This way, you can compare the lists and see that JDK 9 introduced the following new jcmd commands:
- Compiler.queue: This prints the methods queued for compilation with either C1 or C2 (separate queues)
- Compiler.codelist: This prints n-methods (compiled) with full signature, address range, and state (alive, non-entrant, and ...