[TroubleShooting] Deprecated Gradle features

Trouble Shooting history

When I run gradle, I got below message.

$ Deprecated Gradle features were used in this build, making it incompatible with Gradle 6.0.

So, first I put --warning-mode=all to gradle command like below.

$ ./gradlew clean build --warning-mode=all

And I find DefaultSourceDirectorySet class's constructor has been deprecated (below detail message)

Configure project :
The DefaultSourceDirectorySet constructor has been deprecated. This is scheduled to be removed in Gradle 6.0. Please use the ObjectFactory service to create instances of SourceDirectorySet instead.

Kotlin 1.3.20 was released and also updated in the Gradle repository

so this issue should be solved by updating the Kotlin Gradle plugin to 1.3.20