How I can fix this error; java.lang.ClassNotFoundException: org.gradle.api.internal.plugins.DefaultConvention

It looks like one of your plugins (a jetbrains plugin of some sort) is not compatible with Gradle 6. I'm guessing you could fix the issue by either

• Using an older version of Gradle
• Upgrading to a newer version of the plugin that supports Gradle 6

It seems that the jetbrains plugin is referencing a Gradle class in an "internal" package. These classes are not part of the public API and can change (or be removed) between Gradle versions without notice, hence the NoClassDefFoundError. Ideally plugins should only reference the public API