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POJNI memory management using the Invocation API
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copied!<p>When I'm building a java object using JNI methods, in order to pass it in as a parameter to a java method I'm invoking using the JNI invocation API, how do I manage its memory? </p> <p>Here's what I am working with:</p> <p>I have a C object that has a destructor method that is more complex that <code>free()</code>. This C object is to be associated with a Java object, and once the application is finished with the Java object, I have no more need for the C object.</p> <p>I am creating the Java object like so (error checking elided for clarity):</p> <pre><code>c_object = c_object_create (); class = (*env)->FindClass (env, "my.class.name"); constructor = (*env)->GetMethodID (env, class, "<init>", "(J)V"); instance = (*env)->NewObject (env, class, constructor, (jlong) c_object); method = (*env)->GetMethodID (env, other_class, "doSomeWork", "(Lmy.class.name)V"); (*env)->CallVoidMethod (env, other_class, method, instance); </code></pre> <p>So, now that I'm done with <code>instance</code>, what do I do with it? Ideally, I'd like to leave the garbage collection up to the VM; when it's done with <code>instance</code> it would be fantastic if it also called <code>c_object_destroy()</code> on the pointer I provided to it. Is this possible?</p> <p>A separate, but related question has to do with the scope of Java entities that I create in a method like this; do I have to manually release, say, <code>class</code>, <code>constructor</code>, or <code>method</code> above? The JNI doc is frustratingly vague (in my judgement) on the subject of proper memory management.</p>

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