感谢tim_yates！（为什么这个文档没有出现在谷歌上😧）
以下是kotlin和groovy文档的改编

tasks.named<AbstractCompile>("compileGroovy") {
    // Groovy only needs the declared dependencies
    // (and not longer the output of compileJava)
    classpath = sourceSets.main.get().compileClasspath
}

tasks.named<AbstractCompile>("compileKotlin") {
    // Java also depends on the result of Groovy compilation
    // (which automatically makes it depend of compileGroovy)
    classpath += files(sourceSets.main.get().withConvention(GroovySourceSet::class) { groovy }.classesDirectory)
}