Surprised error when creating the application “Could not find an external class” after upgrading to gradle3.1.0-beta1 (Android Studio 3.1 Beta1)

Question

run: ./ gradlew clean assembleDebug

Exception in thread "main" java.lang.NullPointerException: Couldn't find outer class xxxxx/SomeClass$someMethod$1$1$2 of xxxx/SomeClass$someMethod$1$1$2$1

execution failed for task ':app:transformClassesWithDesugarForDevDebug'.

issue

Same issue https://www.reddit.com/r/androiddev/comments/7u8tug/android_studio_31_beta_1_is_available/

Answer 1

Solution: https://issuetracker.google.com/issues/72750890#comment10

the error is also populated in JB.