What's the proper way to extend java side on android?

[lazytiger]

1、I need to call the Java method in Rust code. How can I get a JNIEnv parameter in the mobile framework?
2、I need to implement a VPN service on the Java side. What's the best way to integrate it into the current framework, since the Java side is auto-generated now, where should I put my custom code?

[lazytiger]

1、use ndk-context
2、use a compiled jar?