running flutter in vs code shows Running with sound null safety - flutter

Question

This is my first app in flutter using VS Code.
While I try to run my program via terminal using command flutter run shows:
Using hardware rendering with device Android SDK built for x86. If you notice graphics artifacts, consider enabling software rendering with"--enable-software-rendering".
Launching lib\main.dart on Android SDK built for x86 in debug mode...
Warning: Mapping new ns http://schemas.android.com/repository/android/common/02 to old ns http://schemas.android.com/repository/android/common/01
Warning: Mapping new ns http://schemas.android.com/repository/android/generic/02 to old ns http://schemas.android.com/repository/android/generic/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/addon2/02 to old ns http://schemas.android.com/sdk/android/repo/addon2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/addon2/03 to old ns http://schemas.android.com/sdk/android/repo/addon2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/repository2/02 to old ns http://schemas.android.com/sdk/android/repo/repository2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/repository2/03 to old ns http://schemas.android.com/sdk/android/repo/repository2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/sys-img2/03 to old ns http://schemas.android.com/sdk/android/repo/sys-img2/01
Warning: Mapping new ns http://schemas.android.com/sdk/android/repo/sys-img2/02 to old ns http://schemas.android.com/sdk/android/repo/sys-img2/01
Running Gradle task 'assembleDebug'... 12.3s
√ Built build\app\outputs\flutter-apk\app-debug.apk.
Syncing files to device Android SDK built for x86... 9.4s
Flutter run key commands.
r Hot reload.
R Hot restart.
h List all available interactive commands.
d Detach (terminate "flutter run" but leave application running).
c Clear the screen
q Quit (terminate the application on the device).
Running with sound null safety
An Observatory debugger and profiler on Android SDK built for x86 is available at: http://127.0.0.1:63186/_rjqXM3bogc=/
The Flutter DevTools debugger and profiler on Android SDK built for x86 is available at:
http://127.0.0.1:9101?uri=http://127.0.0.1:63186/_rjqXM3bogc=/
After this nothing happens in terminal neither virtual device opens up. What is happening?
When running flutter doctor shows everything ok.

Answer 1

This error happens because of gradle version this is an error like this question just update your gradle in Your_Flutter_App > android > build.gradle, dependencies block to new versions like:
classpath 'com.android.tools.build:gradle:7.0.2'
check buildToolsVersion and compileSdkVersion in /android/app/build.gradle if didnt work.