Scala

https://docs.scala-lang.org/tour/basics.html https://www.scala-lang.org/documentation/your-first-lines-of-scala.html

Kotlin

https://spring.io/guides/tutorials/spring-boot-kotlin/ https://github.com/Kotlin/kotlin-examples/blob/master/tutorials/spring-boot-restful/build.gradle https://www.baeldung.com/kotlin-allopen-spring https://www.baeldung.com/spring-boot-kotlin

groovy

https://www.tutorialspoint.com/gradle/gradle_build_a_groovy_project.htm http://groovy-lang.org/structure.html https://examples.javacodegeeks.com/enterprise-java/spring/spring-groovy-tutorial/ https://dev.to/jorge_rockr/spring-boot--groovy-from-zero-to-hero-5d39 https://medium.com/inside-bukalapak/rest-api-with-spring-boot-groovy-fa9d5b1e5274 https://www.educba.com/groovy-vs-java/