Android ICS : JNI error attempt to use stale local reference 0x1

Question

After upgrading my phone to android 4.03 ics my game dosent open anymore ,it just closes without any error messege on deviCe and with this on eclipse

04-02 16:         


        

Answer 1

@Ernest and @Ilya are correct. Note that the problem manifests itself in other ways too, not just signature mismatches. There is another very specific case that I ran into, which was explained here in the Android' team's blog under the section:

Bug: Mistakenly assuming FindClass() returns global references

FindClass() returns local references. Many people assume otherwise. In a system without class unloading (like Android), you can treat jfieldID and jmethodID as if they were global. (They’re not actually references, but in a system with class unloading there are similar lifetime issues.) But jclass is a reference, and FindClass() returns local references. A common bug pattern is “static jclass”. Unless you’re manually turning your local references into global references, your code is broken.

Basically I was caching the jclass returned by FindClass in a global variable as is, but it turns out this value (as of Android 4?) is now a localref. As a result, I had to convert it into a globalref like so:

jclass jc = env->FindClass(callbacks.name);
// Since Android ICS, class references are not global so we need to peg a
// global reference to the jclass returned by FindClass(), otherwise we get
// following error in the log:
// "JNI ERROR (app bug): attempt to use stale local reference 0xHHHHHHHH".
callbacks._class = static_cast(env->NewGlobalRef(jc));

After a lot of head-scratching, this fixed the issue for me.