What is the naming convention for java native interface method and module name?

Question

I am able to follow a jni tutorial just fine. But when I change the method name, I run into trouble. Is there a naming convention I need to follow? The tutorial used HelloJNI as the module name, and library name. I used "useaaacom".

Answer 1

From Oracle's documentation:

Dynamic linkers resolve entries based on their names. A native method name is concatenated from the following components:

• the prefix Java_
• a mangled fully-qualified class name
• an underscore (_) separator
• a mangled method name
• for overloaded native methods, two underscores (__) followed by the mangled argument signature

So if you have the following:

package com.foo.bar;

class Baz {
    public native void Grill(int i);
}

Then the corresponding C function should be:

JNIEXPORT void JNICALL Java_com_foo_bar_Baz_Grill(JNIEnv *env, jobject thiz, jint i);

If you have an underscore in the Java method name:

public native void A_Grill(int i);

Then the C function would be:

JNIEXPORT void JNICALL Java_com_foo_bar_Baz_A_1Grill(JNIEnv *env, jobject thiz, jint i);

The _1 escape sequence matches the _ in A_Grill.