FAILURE: Build failed with an exception. * What went wrong: Could not initialize class org.codehaus.groovy.runtime.InvokerHelper flutter code example

Example: Could not initialize class org.codehaus.groovy.runtime.InvokerHelper

This is because of the gradle version:

In your project
go to: gradle / wrapper / gradle-wrapper.properties /

change the version:
distributionUrl=https\://services.gradle.org/distributions/gradle-6.1.1-all.zip

to
distributionUrl=https\://services.gradle.org/distributions/gradle-6.3-all.zip

Source
https://stackoverflow.com/questions/35000729/android-studio-could-not-initialize-class-org-codehaus-groovy-runtime-invokerhel