idea.gradle

idea {
    project {
        languageLevel = '8'
    }
    module {
        sourceDirs += file('src/main/scala')
        sourceDirs += file('src/main/java')

        testSourceDirs += file('src/test/scala')
        testSourceDirs += file('src/test/java')

        jdkName = '1.8'
    }
}