Android Unity Plugin problem

I am trying to make a Android plugin for unity but i am getting this error "AndroidJavaException java.lang.ClassNotFoundException: com.example.androidhook"

I have this as my Android code

 package com.example.androidhook;
 
 import android.os.Bundle;
 import android.util.Log;
 
 import com.unity3d.player.UnityPlayer;
 import com.unity3d.player.UnityPlayerActivity;
 
 public class UnityBridge extends UnityPlayerActivity {
 
     @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          Log.d("TAG","Static method was called");
          UnityPlayer.UnitySendMessage("GameObject", "Hello", "READY");
      }
     
  
    
 }
 

And here is my manifest file

 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.androidhook">
   <application android:icon="@drawable/app_icon" android:label="@string/app_name">
     <activity android:name=".UnityBridge"
              android:label="@string/app_name"
              android:configChanges="fontScale|keyboard|keyboardHidden|locale|mnc|mcc|navigation|orientation|screenLayout|screenSize|smallestScreenSize|uiMode|touchscreen">
         <intent-filter>
             <action android:name="android.intent.action.MAIN" />
             <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
     </activity>
   </application>
 </manifest>

Here is my C# code

 using UnityEngine;
 using System.Collections;
 
 public class Done : MonoBehaviour {
 
     public GUIText guiText;
     
     public void Start ()
     {
         Invoke ("adds", 2.0f);
     }
 
     public void adds()
     {
         AndroidJNI.AttachCurrentThread();
         AndroidJavaClass androidClass = new AndroidJavaClass("com.example.androidhook");
     }
 
     public void Hello()
     {
         guiText.text = "hello";
     }
 
 }

I have the manifest file and the .jar file in the folder Plugins/Android.

Please could you advise me on what i need to do next thanks