Vert.x

Vert.x is another tool kit provided by the Eclipse Foundation project used to build a JVM-based Reactive System. It also provides an implementation of Reactive Streams specifications similar to Ratpack. Vert.x supports and allows the use of RxJava to build a Reactive System. Needless to say, Vert.x is event based and non-blocking in nature. It supports various programming languages, like Java, JavaScript, Ruby, Groovy, Ceylon, Scala, Kotlin, and so on. You can learn more about it at:  https://vertx.io.