server code

package com.example.firstapp;

import androidx.appcompat.app.AppCompatActivity;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";

    EditText editText ;

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


    private boolean isPackageInstalled(String packageName, PackageManager packageManager) {
        try {
            packageManager.getPackageInfo(packageName, 0);
            return true;
        } catch (PackageManager.NameNotFoundException e) {
            return false;
        }
    }

    public void reject(View view) {

        final Intent intent=new Intent();
        intent.setAction("com.example.secondapp");
        intent.putExtra("action","reject");
        intent.addFlags(Intent.FLAG_INCLUDE_STOPPED_PACKAGES); // to insure app even if it not running
        intent.setComponent(
                new ComponentName("com.example.secondapp","com.example.secondapp.MyReceiver"));
        sendBroadcast(intent);
    }

    public void accept(View view) {

        if(isPackageInstalled("com.example.secondapp" , getPackageManager()))
        {
            Intent intent = new Intent();
            intent.setComponent(new ComponentName("com.example.secondapp","com.example.secondapp.MainActivity"));
            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            intent.addFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);
            startActivity(intent);

        }else {
            Toast.makeText(getApplicationContext(), " app not installed ", Toast.LENGTH_SHORT).show();
        }
    }
}

server broadcast receiver :

package com.example.firstapp;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;

public class MyReciever extends BroadcastReceiver {

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = "I received from Client " + intent.getStringExtra("action");
        Toast.makeText(context, action, Toast.LENGTH_SHORT).show();
    }
}

Manifest file

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.firstapp">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">


        <receiver
            android:name=".MyReciever"
            android:enabled="true"
            android:exported="true">

        </receiver>

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Notes

• first app represent server code
• second app represent client app
• second app is similar to first app.