react-native-fbsdk in React Native 0.29.+

MainActivity.java

public class MainActivity extends ReactActivity {

    /**
     * Returns the name of the main component registered from JavaScript.
     * This is used to schedule rendering of the component.
     */
    @Override
    protected String getMainComponentName() {
        return "MyApp";
    }
    
    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        MainApplication.getCallbackManager().onActivityResult(requestCode, resultCode, data);
    }
}

MainApplication.java

public class MainApplication extends Application implements ReactApplication {

  private static CallbackManager mCallbackManager = new CallbackManager.Factory().create();
  
  @Override
  public void onCreate() {
    FacebookSdk.sdkInitialize(this);
  }

  private final ReactNativeHost mReactNativeHost = new ReactNativeHost(this) {
    @Override
    protected boolean getUseDeveloperSupport() {
      return BuildConfig.DEBUG;
    }

    @Override
    protected List<ReactPackage> getPackages() {
      return Arrays.<ReactPackage>asList(
          new MainReactPackage(),
          new FBSDKPackage(mCallbackManager),
      );
    }
  };

  @Override
  public ReactNativeHost getReactNativeHost() {
      return mReactNativeHost;
  }

  protected static CallbackManager getCallbackManager() {
    return mCallbackManager;
  }
}

Figured it out! It was my mistake. I tried to import MainReactPackage twice.

return Arrays.<ReactPackage>asList(
new MainReactPackage(),
new ReactNativePushNotificationPackage(),
new MainReactPackage(),
new FBSDKPackage(mCallbackManager)
);

Just gonna leave it here for anyone who runs into the same mistake.

Thank you, that was helpful :)