JNI failed when called with String argument

Question

I am trying to call a function implemented in C from my Android code. The code stream is as follows:

In onCreate () of my main activity, I have this:

    TestClass tc = new TestClass();
    tc.act();

This is TestClass:

package bar.foo;

public class TestClass {
    static {
        System.loadLibrary("testclass");
    }
    public native void doStuff1(String s);
    public native void doStuff2(String s1, String s2);

    TestClass() { }
    public void act() {
        doStuff1 ("Foo");
        doStuff2 ("Bar", "Baz");
    }
}

And testclass.c:

#include <stdio.h>
#include <string.h>
#include <jni.h>
#include <android/log.h>

#define alprint __android_log_print

#define METHOD_SIGNATURE_1 Java_bar_foo_TestClass_doStuff1
#define METHOD_SIGNATURE_2 Java_bar_foo_TestClass_doStuff2

void METHOD_SIGNATURE_1(JNIEnv* env, jstring s) {

    const char *ns;
    int jsLen;

    /* Extract strings */
    ns = (*env)->GetStringUTFChars(env, s, NULL);
        jsLen = (*env)->GetStringUTFLength(env, s);

        alprint(6, "doStuff1", "Text = %s [%d]\n", ns, jsLen);

    (*env)->ReleaseStringUTFChars(env, s, ns);

        return;
}

void METHOD_SIGNATURE_2(JNIEnv* env, jstring s1, jstring s2) {

    const char *ns1;
    const char *ns2;
    int js1Len;
        int js2Len;

    /* Extract strings */
    ns1 = (*env)->GetStringUTFChars(env, s1, NULL);
        js1Len = (*env)->GetStringUTFLength(env, s1);
        ns2 = (*env)->GetStringUTFChars(env, s2, NULL);
        js2Len = (*env)->GetStringUTFLength(env, s2);

        alprint(6, "doStuff2", "Text(1) = %s [%d]\n", ns1, js1Len);
        alprint(6, "doStuff2", "Text(2) = %s [%d]\n", ns2, js2Len);

    (*env)->ReleaseStringUTFChars(env, s1, ns1);
    (*env)->ReleaseStringUTFChars(env, s2, ns2);

        return;
}

This compiles fine and runs on my Android device (Nexus 5 running Android 5.1), but the crash starts with:

JNI DETECTED ERROR IN APPLICATION: jstring has wrong type: bar.foo.TestClass

A full emergency reset is here: http://pastebin.com/C0M98Uzb

I rack my brains over it from last night; Does anyone know what this means?

Answer 1

JNI- - Java, ( ). thiz :

void METHOD_SIGNATURE_1(JNIEnv* env, jobject thiz, jstring s)
void METHOD_SIGNATURE_2(JNIEnv* env, jobject thiz, jstring s1, jstring s2)