A helper class for AdMob ads

Ads.java

import android.app.Activity;
import android.location.Location;
import android.view.View;

import com.google.android.gms.ads.AdListener;
import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdView;
import com.google.android.gms.ads.MobileAds;

/*
 * A helper class for AdMob ads. 
 * This class expects a resource string called "ad_id" that is set to your AdMob App ID.
 * Test devices can be added by using a resource string array called "test_devices".
 */
public class Ads {

    public static void initialize(Activity activity) {
        MobileAds.initialize(activity, activity.getResources().getString(R.string.ad_id));
    }

    public static void loadAd(Activity activity, int id) {
        final AdView adView = activity.findViewById(id);

        if (adView == null)
            return;

        adView.setVisibility(View.GONE);

        AdRequest.Builder builder = new AdRequest.Builder();
        AddTestDevices(activity, builder);

        // builder.setLocation();
        // builder.setBirthday();
        // builder.setGender();
        
        AdRequest adRequest = builder.build();

        adView.loadAd(adRequest);
        adView.setAdListener(new AdListener() {
            @Override
            public void onAdLoaded() {
                adView.setVisibility(View.VISIBLE);
            }

            @Override
            public void onAdFailedToLoad(int i) {
                adView.setVisibility(View.GONE);
            }
        });
    }

    public static void AddTestDevices(Activity activity, AdRequest.Builder builder) {
        String[] testDevices = activity.getResources().getStringArray(R.array.test_devices);
      
        for (String testDevice : testDevices) {
            if (!testDevice.isEmpty())
                builder.addTestDevice(testDevice);
        }
    }

}

can you add how to use it ?