jni

Minimal Java Native Interface bindings. The package provides #[repr(C)] mirrors of the JVM's jni.h dispatch tables, JNINativeInterface (the JNIEnv function table) and JNIInvokeInterface (the JavaVM table), plus the jint / jlong / jobject type aliases.

The JVM hands you a pointer to one of these tables; you read a function pointer out of it and call it through env, exactly as C's (*env)->FindClass(env, ...) does:

import "jni/jni" as jni;

fn get_version(env: jni::JNIEnv) -> jni::jint {
    let f: fn(jni::JNIEnv) -> jni::jint = unsafe { (*env).GetVersion };
    return unsafe { f(env) };
}

It is deliberately "min": the table is defined through the Call*Method family, with enough preceding fields to keep every offset correct. Extend it for later methods (GetMethodID, NewStringUTF, array ops) by appending fields in jni.h order. A layout #[test] pins the table sizes (344 / 64 bytes on 64-bit) so a dropped or mistyped field is caught immediately. The package is also the smallest demonstration that cpc handles function-pointer struct fields and a type that references itself through a pointer (JNIEnv = *JNINativeInterface).