Note that this is the default, standardized behavior. If you're willing to use Oracle (and I think by extension OpenJDK)-specific features then there are some f

Note that this is the default, standardized behavior. If you're willing to use Oracle (and I think by extension OpenJDK)-specific features then there are some functions with "unsafe" in the name that allows you to hand over memory directly to native code, instead of copying it over. The default behaviour is to copy all memory passed in and out of the JVM, so as to avoid native+java+GC messing with the same memory area (potentially at the same time).