jni-rs-bindings

name	jni-rs-bindings
description	jni-rs conventions for exposing a Rust core to Java/JVM: JNI export naming, JNIEnv usage, string conversion, exception checks/throws, global references, and library loading. Load when generating or reviewing jni-rs Java/JVM bindings for a Rust library.

• Use jni crate for Rust-Java/JVM interop. Functions must be #[no_mangle] pub extern "system".
• Follow JNI naming: Java_com_example_ClassName_methodName. Match Java native method signatures exactly.
• Use JNIEnv for all JNI operations. Access Java types via JObject, JString, JClass wrappers.
• String conversion: env.get_string(&jstring) to read, env.new_string("value") to create.
• Error handling: check env.exception_check() after JNI calls. Throw Java exceptions via env.throw_new().
• Global references (env.new_global_ref()) for objects accessed across threads or native calls.
• Build with cargo build --release to produce shared library. Load in Java with System.loadLibrary().
• Test Java side with JUnit, Rust core logic with standard #[test]. Integration tests via JNI calls.
• Keep JNI layer thin — business logic in Rust, Java provides API surface.
• Memory: JNI local references are auto-freed on native return. Use env.delete_local_ref() in loops.
• Anti-patterns: holding JNI references across threads without global refs, ignoring exception checks, unwrap() in JNI functions.