At least since the release of Java 8, functional programming has become mainstream in the Java community. Things like collection processing, lazy evaluation and concurrent programming are much easier to describe in a functional style than in the traditional procedural or object-oriented way. Xtend is a Java dialect hosted at Eclipse. Designed to remove the syntactic noise, it offers a superior syntax and additional abstractions to provide the full power of functional programming to Java developers. As it compiles to Java 5 code, it will enable functional programming even for Android and GWT developers. In this tutorial, you will learn the basic principles of functional programming and the Xtend idioms to write code the functional way: concise, easy to understand, and yet powerful. No prior knowledge of functional programming or Xtend required.