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javacjava-native-interface

Creating an Integer Object in JNI

I want an Integer object to be return to the java layer from the JNI. The following code crashes when calling NewObject(env, interger, init, rc). What is the proper way to create a Integer object and return it?

jint rc = 0;

jclass intClass = (*env)->FindClass(env, "java/lang/Integer");
if (intClass == NULL) {
    return NULL;
}
jmethodID init =  (*env)->GetMethodID(env, intClass, "intValue", "()I");
if (init == NULL) {
    return NULL;
}
jobject rc_obj = (*env)->NewObject(env, intClass, init, rc);
if (rc_obj == NULL) {
    return NULL;
}

return rc_obj;

Thanks!

Solution

  • Try this:

    jclass cls = (*env)->FindClass(env, "java/lang/Integer");
jmethodID midInit = (*env)->GetMethodID(env, cls, "<init>", "(I)V");
if (NULL == midInit) return NULL;
jobject newObj = (*env)->NewObject(env, cls, midInit, number);