JNI | Exception on return from native code | IncompatibleClassChangeError: invoking method from interface not implemented by class

Weird one this,

Both my Java and C code seem to be working fine. However, when everything is done in the C code and the program would continue through the rest of the Java implementation the below Exception is thrown.

If forced to I'll simply wrap the call to native code in a try/catch but It worries me that an exception is being thrown for a reason unknown to me? Has anyone seen this before?

JavaCInterface.java (Extends Thread):

static {
    Log.v(JavaCInterface.class.toString(), "Loading native libraries");
    System.loadLibrary("JavaCInterface");
}

public native void cFunction(); 

@Override
public void run() {
    super.run();
    cFunction(); // Exception thrown when control is returned here
    return;
}   

JavaCInterface.cpp:

JNIEXPORT void JNICALL Java_com_test_jni_JavaCInterface_cFunction(JNIEnv * env, jobject thiz)
{
    ... // Stuff happens here
    logVerbose("Leaving Native Code"); // This gets logged fine and is the last line of the native method

}

Weird no? Any 开发者_高级运维thoughts?

ERROR/AndroidRuntime(2379): java.lang.IncompatibleClassChangeError: invoking method from interface not implemented by class
ERROR/AndroidRuntime(2379):     at com.test.jni.JavaCInterface.cFunction(Native Method)

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This error was actually caused by a "GetMethodID" failing unchecked previously in the code. Had to track this down like ViTo said by cutting to code up bit by bit