title: java.lang.VerifyError: Cannot inherit from final class with Firebase Admin
body: <p>I am trying to create a java program with Eclipse to take care of some things in my firebase realtime database. My code:</p>
  
  <pre><code>package server;
  
  import java.io.FileInputStream;
  import java.io.IOException;
  
  import com.google.auth.oauth2.GoogleCredentials;
  import com.google.firebase.FirebaseApp;
  import com.google.firebase.FirebaseOptions;
  import com.google.firebase.database.DataSnapshot;
  import com.google.firebase.database.DatabaseError;
  import com.google.firebase.database.DatabaseReference;
  import com.google.firebase.database.FirebaseDatabase;
  import com.google.firebase.database.ValueEventListener;
  
  
  
  public class Main {
  
      public static void main(String[] args) throws IOException {
          // Fetch the service account key JSON file contents
          FileInputStream serviceAccount = new FileInputStream("src/server/something.json");
  
          // Initialize the app with a service account, granting admin privileges
          FirebaseOptions options = new FirebaseOptions.Builder().setCredentials(GoogleCredentials.fromStream(serviceAccount)).setDatabaseUrl("https://something.firebaseio.com").build();
          FirebaseApp.initializeApp(options);
  
          // As an admin, the app has access to read and write all data, regardless of Security Rules
          DatabaseReference ref = FirebaseDatabase.getInstance().getReference("Status");
          ref.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
              int status = dataSnapshot.getValue(Integer.class);
              System.out.println(status);
            }
  
            @Override
            public void onCancelled(DatabaseError error) { }
          });
  
      }
  
  }
  </code></pre>
  
  <p>My errors:</p>
  
  <pre><code>Exception in thread "main" java.lang.VerifyError: Cannot inherit from final class
      at java.base/java.lang.ClassLoader.defineClass1(Native Method)
      at java.base/java.lang.ClassLoader.defineClass(Unknown Source)
      at java.base/java.security.SecureClassLoader.defineClass(Unknown Source)
      at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(Unknown Source)
      at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(Unknown Source)
      at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(Unknown Source)
      at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(Unknown Source)
      at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(Unknown Source)
      at java.base/java.lang.ClassLoader.loadClass(Unknown Source)
      at com.google.api.client.googleapis.util.Utils.getDefaultTransport(Utils.java:51)
      at com.google.firebase.FirebaseOptions$Builder.&lt;init&gt;(FirebaseOptions.java:216)
      at server.Main.main(Main.java:24)
  </code></pre>
  
  <p>My imports in the project:
  firebase-admin-6.3.0.jar ; google-api-client-1.24.1.jar ; google-api-client-http-1.2.3-alpha.jar ; google-api-client-xml-1.2.3-alpha.jar ; google-auth-library-oauth2-http-0.10.0.jar ; google-http-client-1.24.1.jar .
  And a picture of the whole thing: <a href="https://image.ibb.co/kqNMne/whole.png" rel="nofollow noreferrer">https://image.ibb.co/kqNMne/whole.png</a></p>