Chapter 1. Your way to Groovy One main factor in the upward trend of animal life has been the power of wandering. --Alfred North Whitehead Welcome to the world of Groovy. You've heard of Groovy on blogs and mailing lists. Maybe you've seen a snippet here and there. Perhaps a colleague has pointed out a page of your code and claimed the same work could be done in just a few lines of Groovy. Maybe you only picked up this book because the name is catchy. Why should you learn Groovy? What payback can you expect? Groovy will give you some quick wins, whether it's by making your Java code simpler to write, by automating recurring tasks, or by supporting ad-hoc scripting for your daily work as a programmer. It will give you longer- term wins by making your code simpler to read. Perhaps most important, it's fun to use. Learning Groovy is a wise investment. Groovy brings the power of advanced language features such as closures, dynamic typing, and the meta object protocol to the Java platform. Your Java knowledge will not become obsolete by walking the Groovy path. Groovy will build on your existing experience and familiarity with the Java platform, allowing you to pick and choose when you use which tool--and when to combine the two seamlessly. If you have ever marveled at the Ruby folks who can implement a full-blown web application in the afternoon, the Python guys juggling collections, the Perl hackers managing a server farm with a few keystrokes, or Lisp gurus turning their whole codebase upside-down with a tiny change, then think about the language features they have at their disposal. The goal of Groovy is to provide language capabilities of comparable impact on the Java platform, while obeying the Java object model and keeping the perspective of a Java programmer. This first chapter provides background information about Groovy and everything you need to know to get started. It starts with the Groovy story: why Groovy was created, what considerations drive its design, and how it positions itself in the landscape of languages and technologies. The next section expands on Groovy's merits and how they can make life easier for you, whether you're a Java programmer, a script aficionado, or an agile developer. We strongly believe that there is only one way to learn a programming language: by trying it. We present a variety of scripts to demonstrate the compiler, interpreter, and shells, before listing some plug-ins available for widely used IDEs and where to find the latest information about Groovy. By the end of this chapter, you will have a basic understanding of what Groovy is and how you can experiment with it. We--the authors, the reviewers, and the editing team--wish you a great time programming Groovy and using this book for guidance and reference. 1.1. The Groovy story At GroovyOne 2004--a gathering of Groovy developers in London--James Strachan gave a keynote address telling the story of how he arrived at the idea of inventing Groovy. Some time ago, he and his wife were waiting for a late plane. While she went shopping, he visited an Internet café and spontaneously decided to go to the Python web site and study the language. In the course of this 1