How can I programmatically force stop an Android app with Java?

get the process ID of your application, and kill that process onDestroy() method

@Override
public void onDestroy()
 {
    super.onDestroy();

    int id= android.os.Process.myPid();
    android.os.Process.killProcess(id);
 }

or

getActivity().finish();
System.exit(0);

and if you want to kill other apps from your activity, then this should work

You can send the signal using:

Process.sendSignal(pid, Process.SIGNAL_KILL);

To completely kill the process, it's recommended to call:

ActivityManager.killBackgroundProcesses(packageNameToKill)

before sending the signal.

Please, note that your app needs to own the KILL_BACKGROUND_PROCESSES permission. Thus, in the AndroidManifest.xml, you need to include:

<uses-permission android:name="android.permission.KILL_BACKGROUND_PROCESSES" />

Try to use following code

    finish(); // for stopping Current Activity

    // add this line for Removing Force Close

    @Override
        protected void onDestroy() {
    // closing Entire Application
            android.os.Process.killProcess(android.os.Process.myPid());
            super.onDestroy();
        }
    }

May be this solution will help you Force Close an app programmatically