unable to hook onCreate() using frida for android application

Question

I am trying to hook onCreate() of android application using frida. Here is my activity code - .

package com.example;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.telephony.TelephonyManager;
import android.util.Log;

public class UnreachableCode extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_unreachable_code);
    }

    //this method is never called
    private void unreachable(){
        TelephonyManager tm =(TelephonyManager)getBaseContext().getSystemService(Context.TELEPHONY_SERVICE);
        String deviceid = tm.getDeviceId();
        
        Log.i("ID", deviceid);
    }
    
}

Now, in above code unreachable() is never called. But I want to override onCreate() and want to call unreachable() from it. I have tried following code --

import frida
import sys

def on_message(message,data):
    print(message)

jscode = """Java.perform(function() {
 console.log("[ * ] Starting implementation override...")
 var MainActivity = Java.use("com.example.UnreachableCode");
 MainActivity.onCreate.overload("android.os.Bundle").implementation = function(var_0){
     var ret = this.onCreate.overload("android.os.Bundle").call(this,var_0);
     console.log("[ + ] Calling function unreachable");
     this.unreachable();
 };
 send("Hooks installed.");
});
"""
try:
    device = frida.get_usb_device().attach('com.example')
    script = device.create_script(jscode)
    script.on('message',on_message)
    print('[ * ] Running Frida Demo application, Loading script now')
    script.load()
    sys.stdin.read()
except KeyboardInterrupt:
    print ("[!] Killing app...")

This is not working. I am not much familiar with frida, so I need expert's advice. frida version -- 15.2.2, Android - 9

Edit ---- Updated second block of code.