This [JEP] reduces latency by implementing region pinning in G1, so that garbage collection need not be disabled during Java Native Interface (JNI) critical regions.

Java threads that use native code do not stall garbage collections any more. Garbage collections will execute regardless of native code keeping references to Java objects. The garbage collection will keep objects that may be accessed by native code in place, collecting garbage only in surrounding heap areas but will be otherwise unaffected.

[JEP]: https://openjdk.org/jeps/423 "JEP 423: Region Pinning for G1"