Do follow some steps:
Go to flutter_app => android => gradle => wrapper directory
Delete gradle-wrapper.jar file
Open and edit gradle-wrapper.properties file
Change distributionUrl=https://services.gradle.org/distributions/gradle-x.x.x-all.zip to gradle-6.4.1-all.zip or latest
On terminal use flutter run command
I solved my issue, hopefully yours
#windows users
This can be solved by adding environment variable for jdk. Or delete the .gradle folder under C:users'Your username'
#linux users
delete the .gradle folder under /home/user_name