Question

I’m trying to call a Java method from my native code, but it fails. I cannot call the method with a const string (i.e. “string” as a parameter nor by the following way.
If I remove the char[] parameter from the method and call it from the native only with the int parameter it’s work. So the problem is the char[] parameter.

I have the Java class Stats:

public class Stats {

    HashMap<String, Integer> mStats;

    public Stats() {
        mStats = new HashMap<String, Integer>();
    }

    public void put(char[] key, int value) {
        mStats.put(new String(key), value);
    }

}

And a native function

void Java_com_..._testObject(JNIEnv* env, jobject javaThis,
        jobject jStatsObj) {
    jclass jstatistics_class = env->GetObjectClass(jStatsObj);
    jmethodID jput_method = env->GetMethodID(jstatistics_class, "put", "(C[I)V");
    char s[]={"hello"};
    env->CallIntMethod(jStatsObj, jput_method, s, 3);
}

Answer 1

You have the method signature wrong.

(C[I)V means void method(char, int[])

You need ([CI)V.

Source: this page.