This modules relies on Sys::jvm, Sys::jni_env and
Sys::create_default_jvm to get a handle on a JVM. You can adapt the
behavior of the FFI and services in this module by redefing
Sys::create_default_jvm and supply your own JVM object. You can manage
multiple java thread by switching the current environment in a redef
of Sys::jni_env, and multiple JVM using Sys::jvm.
See also, the module jvm to control the JVM instances and access JNI functions.
You can use it to further customize the behavior of your code.