Introduction

Xtend is a statically-typed programming language which translates to comprehensible Java source code. Syntactically and semantically Xtend has its roots in the Java programming language but improves on many aspects:

• Extension methods - enhance closed types with new functionality
• Lambda Expressions - concise syntax for anonymous function literals
• ActiveAnnotations - annotation processing on steroids
• Operator overloading - make your libraries even more expressive
• Powerful switch expressions - type based switching with implicit casts
• Multiple dispatch - a.k.a. polymorphic method invocation
• Template expressions - with intelligent white space handling
• No statements - everything is an expression
• Properties - shorthands for accessing and defining getters and setter
• Type inference - you rarely need to write down type signatures anymore
• Full support for Java generics - including all conformance and conversion rules
• Translates to Java not bytecode - understand what is going on and use your code for platforms such as Android or GWT

Unlike other JVM languages Xtend has zero interoperability issues with Java: Everything you write interacts with Java exactly as expected. At the same time Xtend is much more concise, readable and expressive. Xtend’s small library is just a thin layer that provides useful utilities and extensions on top of the Java Development Kit (JDK).

Of course, you can call Xtend methods from Java, too, in a completely transparent way. Furthermore, Xtend provides a modern Eclipse-based IDE closely integrated with the Eclipse Java Development Tools (JDT), including features like call-hierarchies, rename refactoring, debugging and many more.

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