...
// 1. Import the plugin class.
import com.microsoft.codepush.react.CodePush;

public class MainApplication extends Application implements ReactApplication {

    private final ReactNativeHost mReactNativeHost = new ReactNativeHost(this) {
        ...
        // 2. Override the getJSBundleFile method in order to let
        // the CodePush runtime determine where to get the JS
        // bundle location from on each app start
        @Override
        protected String getJSBundleFile() {
            return CodePush.getJSBundleFile();
        }

        @Override
        protected List<ReactPackage> getPackages() {
            // 3. Instantiate an instance of the CodePush runtime and add it to the list of
            // existing packages, specifying the right deployment key. If you don't already
            // have it, you can run "code-push deployment ls <appName> -k" to retrieve your key.
            return Arrays.<ReactPackage>asList(
                new MainReactPackage(),
                new CodePush("deployment-key-here", MainApplication.this, BuildConfig.DEBUG)
            );
        }
    };
}

@Override
protected String getJSMainModuleName() {
    return "index";
}

...
// 1. Import the plugin class.
import com.microsoft.codepush.react.CodePush;

public class MyReactActivity extends Activity {
    private ReactRootView mReactRootView;
    private ReactInstanceManager mReactInstanceManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        ...
        mReactInstanceManager = ReactInstanceManager.builder()
                // ...
                // Add CodePush package
                .addPackage(new CodePush("deployment-key-here", getApplicationContext(), BuildConfig.DEBUG))
                // Get the JS Bundle File via Code Push
                .setJSBundleFile(CodePush.getJSBundleFile())
                // ...
                
                .build();
        mReactRootView.startReactApplication(mReactInstanceManager, "MyReactNativeApp", null);

        setContentView(mReactRootView);
    }

    ...
}

...
// 1. Import the plugin class (if you used RNPM to install the plugin, this
// should already be done for you automatically so you can skip this step).
import com.microsoft.codepush.react.CodePush;

public class MainActivity extends ReactActivity {
    // 2. Override the getJSBundleFile method in order to let
    // the CodePush runtime determine where to get the JS
    // bundle location from on each app start
    @Override
    protected String getJSBundleFile() {
        return CodePush.getJSBundleFile();
    }

    @Override
    protected List<ReactPackage> getPackages() {
        // 3. Instantiate an instance of the CodePush runtime and add it to the list of
        // existing packages, specifying the right deployment key. If you don't already
        // have it, you can run "code-push deployment ls <appName> -k" to retrieve your key.
        return Arrays.<ReactPackage>asList(
            new MainReactPackage(),
            new CodePush("deployment-key-here", this, BuildConfig.DEBUG)
        );
    }

    ...
}

...
// 1. Declare your ReactNativeHost to extend ReactInstanceHolder. ReactInstanceHolder is a subset of ReactNativeHost, so no additional implementation is needed.
import com.microsoft.codepush.react.ReactInstanceHolder;

public class MyReactNativeHost extends ReactNativeHost implements ReactInstanceHolder {
  // ... usual overrides
}

// 2. Provide your ReactNativeHost to CodePush.

public class MainApplication extends Application implements ReactApplication {

   private final MyReactNativeHost mReactNativeHost = new MyReactNativeHost(this);

   @Override
   public void onCreate() {
     CodePush.setReactInstanceHolder(mReactNativeHost);
     super.onCreate();
  }
}

// 1. Provide your ReactInstanceHolder to CodePush.

public class MainApplication extends Application {

   @Override
   public void onCreate() {
     // ... initialize your instance holder
     CodePush.setReactInstanceHolder(myInstanceHolder);
     super.onCreate();
  }
}

import com.facebook.react.ReactActivity;
import com.reactnativenavigation.controllers.SplashActivity;

public class MainActivity extends SplashActivity {

}

// ...
import com.facebook.react.ReactInstanceManager;

// Add CodePush imports
import com.microsoft.codepush.react.ReactInstanceHolder;
import com.microsoft.codepush.react.CodePush;

public class MainApplication extends NavigationApplication implements ReactInstanceHolder {

	@Override
	public boolean isDebug() {
		// Make sure you are using BuildConfig from your own application
		return BuildConfig.DEBUG;
	}

	protected List<ReactPackage> getPackages() {
		// Add additional packages you require here
		return Arrays.<ReactPackage>asList(
			new CodePush("deployment-key-here", getApplicationContext(), BuildConfig.DEBUG)
		);
	}

	@Override
	public List<ReactPackage> createAdditionalReactPackages() {
		return getPackages();
	}

	@Override
	public String getJSBundleFile() {
        // Override default getJSBundleFile method with the one CodePush is providing
		return CodePush.getJSBundleFile();
	}

	@Override
	public String getJSMainModuleName() {
		return "index";
	}

    @Override
    public ReactInstanceManager getReactInstanceManager() {
        // CodePush must be told how to find React Native instance
        return getReactNativeHost().getReactInstanceManager();
    }
}

import com.reactnativenavigation.NavigationActivity;

public class MainActivity extends NavigationActivity {

}

// ...
import com.facebook.react.ReactInstanceManager;

// Add CodePush imports
import com.microsoft.codepush.react.CodePush;

public class MainApplication extends NavigationApplication {

    @Override
    public boolean isDebug() {
        return BuildConfig.DEBUG;
    }

    @Override
    protected ReactGateway createReactGateway() {
        ReactNativeHost host = new NavigationReactNativeHost(this, isDebug(), createAdditionalReactPackages()) {
            @javax.annotation.Nullable
            @Override
            protected String getJSBundleFile() {
                return CodePush.getJSBundleFile();
            }
            
        };
        return new ReactGateway(this, isDebug(), host);
    }

    @Override
    public List<ReactPackage> createAdditionalReactPackages() {
        return Arrays.<ReactPackage>asList(
	    new CodePush("deployment-key-here", getApplicationContext(), isDebug())
	    //,MainReactPackage , etc...
    }
}

<resources>
   <string name="app_name">my_app</string>
   <string name="CodePushPublicKey">-----BEGIN PUBLIC KEY-----
MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtPSR9lkGzZ4FR0lxF+ZA
P6jJ8+Xi5L601BPN4QESoRVSrJM08roOCVrs4qoYqYJy3Of2cQWvNBEh8ti3FhHu
tiuLFpNdfzM4DjAw0Ti5hOTfTixqVBXTJPYpSjDh7K6tUvp9MV0l5q/Ps3se1vud
M1/X6g54lIX/QoEXTdMgR+SKXvlUIC13T7GkDHT6Z4RlwxkWkOmf2tGguRcEBL6j
ww7w/3g0kWILz7nNPtXyDhIB9WLH7MKSJWdVCZm+cAqabUfpCFo7sHiyHLnUxcVY
OTw3sz9ceaci7z2r8SZdsfjyjiDJrq69eWtvKVUpredy9HtyALtNuLjDITahdh8A
zwIDAQAB
-----END PUBLIC KEY-----</string>
</resources>

new CodePush(
    "deployment-key",
    getApplicationContext(),
    BuildConfig.DEBUG,
    R.string.CodePushPublicKey)

new CodePushBuilder("deployment-key-here",getApplicationContext())
   .setIsDebugMode(BuildConfig.DEBUG)
   .setPublicKeyResourceDescriptor(R.string.CodePushPublicKey)
   .build()