There's a very odd comment in this file: it clearly refers to some method in another file. But what was it for, anyway? Surely the name of a method and its signature is contained in the code. I'd just delete it. /* * Class: java_io_VMConsole * Method: echo * Signature: (Z)Z */ JNIEXPORT jstring JNICALL Java_java_io_VMConsole_readPassword (JNIEnv * env, jclass clazz __attribute__ ((__unused__)), jobject con) { Andrew.