title: React native: error: cannot find symbol after upgrade
body: <p>Hi after importing my react native project expo and upgrading react, I've been have the following problems. </p>
  
  <blockquote>
    <p>C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:5:
    error: cannot find symbol import com.facebook.react.ReactApplication;
                             ^   symbol:   class ReactApplication   location: package com.facebook.react
    C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:13:
    error: cannot find symbol import com.facebook.react.ReactNativeHost;
                             ^   symbol:   class ReactNativeHost   location: package com.facebook.react
    C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:21:
    error: cannot find symbol public class MainApplication extends
    Application implements ReactApplication {
                                                                ^   symbol: class ReactApplication
    C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:23:
    error: cannot find symbol   private final ReactNativeHost
    mReactNativeHost = new ReactNativeHost(this) {
                    ^   symbol:   class ReactNativeHost   location: class MainApplication
    C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:40:
    error: cannot find symbol   public ReactNativeHost
    getReactNativeHost() {
             ^   symbol:   class ReactNativeHost   location: class MainApplication
    C:\Users\user\gramic\android\app\src\main\java\com\shop\MainActivity.java:5:
    error: MainActivity is not abstract and does not override abstract
    method getPackages() in ReactActivity public class MainActivity
    extends ReactActivity {
           ^ C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:23:
    error: cannot find symbol   private final ReactNativeHost
    mReactNativeHost = new ReactNativeHost(this) {
                                                           ^   symbol:   class ReactNativeHost   location: class MainApplication
    C:\Users\user\gramic\android\app\src\main\java\com\shop\MainApplication.java:39:
    error: method does not override or implement a method from a supertype
    @Override   ^</p>
  </blockquote>
  
  <pre><code>    package com.shop;
  
  import android.app.Application;
  
  import com.facebook.react.ReactApplication;
  import com.oblador.vectoricons.VectorIconsPackage;
  import com.corbt.keepawake.KCKeepAwakePackage;
  import com.oblador.vectoricons.VectorIconsPackage;
  import com.github.yamill.orientation.OrientationPackage;
  import com.BV.LinearGradient.LinearGradientPackage;
  import com.brentvatne.react.ReactVideoPackage;
  
  import com.facebook.react.ReactNativeHost;
  import com.facebook.react.ReactPackage;
  import com.facebook.react.shell.MainReactPackage;
  import com.facebook.soloader.SoLoader;
  
  import java.util.Arrays;
  import java.util.List;
  
  public class MainApplication extends Application implements ReactApplication {
  
    private final ReactNativeHost mReactNativeHost = new ReactNativeHost(this) {
      @Override
      public boolean getUseDeveloperSupport() {
        return BuildConfig.DEBUG;
      }
  
      @Override
      protected List&lt;ReactPackage&gt; getPackages() {
        return Arrays.&lt;ReactPackage&gt;asList(
            new MainReactPackage(),
              new VectorIconsPackage(),
              new VectorIconsPackage(),
              new KCKeepAwakePackage(),
              new VectorIconsPackage(),
              new OrientationPackage(),
              new LinearGradientPackage(),
              new ReactVideoPackage()
  
        );
      }
    };
  
    @Override
    public ReactNativeHost getReactNativeHost() {
      return mReactNativeHost;
    }
  
    @Override
    public void onCreate() {
      super.onCreate();
      SoLoader.init(this, /* native exopackage */ false);
    }
  }
  </code></pre>