title: FirebaseAuthPlugin.java:9: error: cannot find symbol import androidx.annotation.NonNull;
body: <p>Note: /opt/sdk/flutter/.pub-cache/hosted/pub.dartlang.org/cloud_firestore-0.12.1/android/src/main/java/io/flutter/plugins/firebase/cloudfirestore/CloudFirestorePlugin.java uses or overrides a deprecated API.
  Note: Recompile with -Xlint:deprecation for details.
  Note: /opt/sdk/flutter/.pub-cache/hosted/pub.dartlang.org/cloud_firestore-0.12.1/android/src/main/java/io/flutter/plugins/firebase/cloudfirestore/CloudFirestorePlugin.java uses unchecked or unsafe operations.
  Note: Recompile with -Xlint:unchecked for details.
  Note: /opt/sdk/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_analytics-3.0.2/android/src/main/java/io/flutter/plugins/firebaseanalytics/FirebaseAnalyticsPlugin.java uses or overrides a deprecated API.
  Note: Recompile with -Xlint:deprecation for details.
  Note: /opt/sdk/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_analytics-3.0.2/android/src/main/java/io/flutter/plugins/firebaseanalytics/FirebaseAnalyticsPlugin.java uses unchecked or unsafe operations.
  Note: Recompile with -Xlint:unchecked for details.
  /opt/sdk/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_auth-0.11.1+5/android/src/main/java/io/flutter/plugins/firebaseauth/FirebaseAuthPlugin.java:9: error: cannot find symbol
  import androidx.annotation.NonNull;
                            ^
    symbol:   class NonNull
    location: package androidx.annotation
  /opt/sdk/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_auth-0.11.1+5/android/src/main/java/io/flutter/plugins/firebaseauth/FirebaseAuthPlugin.java:10: error: cannot find symbol
  import androidx.annotation.Nullable;
                            ^
    symbol:   class Nullable
    location: package androidx.annotation
  /opt/sdk/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_auth-0.11.1+5/android/src/main/java/io/flutter/plugins/firebaseauth/FirebaseAuthPlugin.java:764: error: cannot find symbol
    private void reportException(Result result, @Nullable Exception exception) {
                                                 ^
    symbol:   class Nullable
    location: class FirebaseAuthPlugin
  /opt/sdk/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_auth-0.11.1+5/android/src/main/java/io/flutter/plugins/firebaseauth/FirebaseAuthPlugin.java:668: error: cannot find symbol
      public void onComplete(@NonNull Task task) {
                              ^
    symbol:   class NonNull
    location: class FirebaseAuthPlugin.SignInCompleteListener
  /opt/sdk/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_auth-0.11.1+5/android/src/main/java/io/flutter/plugins/firebaseauth/FirebaseAuthPlugin.java:687: error: cannot find symbol
      public void onComplete(@NonNull Task task) {
                              ^
    symbol:   class NonNull
    location: class FirebaseAuthPlugin.TaskVoidCompleteListener
  /opt/sdk/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_auth-0.11.1+5/android/src/main/java/io/flutter/plugins/firebaseauth/FirebaseAuthPlugin.java:705: error: cannot find symbol
      public void onComplete(@NonNull Task task) {
                              ^
    symbol:   class NonNull
    location: class FirebaseAuthPlugin.GetSignInMethodsCompleteListener
  /opt/sdk/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_auth-0.11.1+5/android/src/main/java/io/flutter/plugins/firebaseauth/FirebaseAuthPlugin.java:540: error: cannot find symbol
                public void onComplete(@NonNull Task task) {
                                        ^
    symbol: class NonNull
  /opt/sdk/flutter/.pub-cache/hosted/pub.dartlang.org/firebase_auth-0.11.1+5/android/src/main/java/io/flutter/plugins/firebaseauth/FirebaseAuthPlugin.java:617: error: cannot find symbol
            public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
                                            ^
    symbol: class NonNull
  8 errors</p>
  
  <p>FAILURE: Build failed with an exception.</p>
  
  <ul>
  <li><p>What went wrong:
  Execution failed for task ':firebase_auth:compileDebugJavaWithJavac'.</p>
  
  <blockquote>
    <p>Compilation failed; see the compiler error output for details.</p>
  </blockquote></li>
  <li><p>Try:
  Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.</p></li>
  <li><p>Get more help at <a href="https://help.gradle.org" rel="nofollow noreferrer">https://help.gradle.org</a></p></li>
  </ul>
  
  <p>BUILD FAILED in 15s</p>
  
  <hr>
  
  <p>Finished with error: Gradle task assembleDebug failed with exit code 1</p>