You might be interested in OpenJDK's new ability to 'cache' classes to accelerate class loading. JEP 483: Ahead-of-Time Class Loading & Linking. It doesn't persist code generated by the JIT, but can improve startup time appreciably.
> This program runs in 0.031 seconds on JDK 23. After doing the small amount of additional work required to create an AOT cache it runs in in 0.018 seconds on JDK 24 — an improvement of 42%.
From https://openjdk.org/jeps/483 :
> This program runs in 0.031 seconds on JDK 23. After doing the small amount of additional work required to create an AOT cache it runs in in 0.018 seconds on JDK 24 — an improvement of 42%.