In JNI, How to access JSONObject's values in j

Question

Using org.json.JSONObject;

Current code

Java Code:

class sample  
{  
    int val = 7;  
    String str = "Hai";  
    public native void callCpp(JSONObject jo);  
    public static void main(String args[])  
    {  
        sample s = new sample();  
        JSONObject jo = new JSONObject();  
        jo.put("val",val);  
        jo.put("str",str);
        s.callCpp(jo);  
    }  
}

CPP Code:

JNIEXPORT void JNICALL Java_sample_callCpp(JNIEnv *env, jobject obj, jobject jobj)  
{  
    jclass cls = env->FindClass("org/json/JSONObject");  
    jmethodID method = env->GetMethodID(cls, "getInt", "(Ljava/lang/String;)I");    

    jint val = env->CallIntMethod(arg, method, env->NewStringUTF("val"));  
    std::cout << "val: " << val << std::endl;    

    jmethodId method2 = env->GetMethodID(cls, "getString", "(Ljava/lang/String;)Ljava/lang/String;");  
    jstring strVal = (jstring) env->CallObjectMethod(arg, method2, env->NewStringUTF("strVal"));  
    const jchar *ptr = env->GetStringUTFChars(strVal, nullptr);  
    std::string strVal_copy(ptr);    

    env->ReleaseStringUTFChars(strVal, ptr);  
    std::cout << "strVal: " << strVal_copy << std::endl;  
}

From this I can retrieve "val" and "str" and use in CPP.

But my problem is, I cannnot do the exact oppposite of this.

I need to send values to "val" and "str" to that JSONObject.

The following seems to be wrong, Help me correct it!

JAVA CODE:

void valFromCPP(JSONObject jo)  
{  
    System.out.println("Val is ::  " + jo.getInt("val"));  
    System.out.println("Str is ::  " + jo.getString("str"));  
}  

CPP CODE:

JNIEXPORT void JNICALL Java_sample_disp(JNIEnv *env, jobject cobj, jobject jsonjobj)  
{  
   jclass jsoncls = env->FindClass("org/json/JSONObject");  
   jclass ccls = env->GetObjectClass(cobj);  

   jobject newObj;  
   jmethodID constructorID = env->GetMethodID(jsoncls,"<init>","()V");  
   newObj = env->NewObject(jsoncls, constructorID);  
   jmethodID putStringID = env->GetMethodID(jsoncls, "put", "(Ljava/lang/String;Ljava/lang/Object;)Lorg/json/JSONObject;");  
   if(putStringID == NULL)  
   {  
       printf("\n putStringID not created!\n");  
       return;
   }  
   jmethodID putIntID = env->GetMethodID(jsoncls, "put", "(Ljava/lang/String;I)Lorg/json/JSONObject;");  

   jmethodID valFromCPPId = env->GetMethodID(ccls, "valFromCPP", "(Lorg/json/JSONObject;)V");  
   newObj = env->CallObjectMethod(newObj, putStringID, env->NewStringUTF("str"), env->NewStringUTF("Hai"));  

   newObj = env->CallObjectMethod(newObj, putIntID, env->NewStringUTF("val"), 7);  
   env->CallVoidMethod(cobj, valFromCPPId, newObj);
}

Im getting the error :

putStringID Not Created  
Exception in thread "main" java.lang.NoSuchMethodError: put  

Even though i made sure there is put method, and it returns "this", which is that object.