What you need for this book
One of the pieces of software required for this book is the Java Development Kit (7 or above), which you can obtain from http://www.oracle.com/technetwork/java/javase/downloads/. JDK is necessary to run and develop applications on the Java platform. The other major software that you'll need is Leiningen (2.5.1 or above), which you can download and install from http://github.com/technomancy/leiningen.
Leiningen is a tool for managing Clojure projects and their dependencies. Throughout this book, we'll use a number of Clojure libraries. Leiningen will download these libraries, and also the Clojure language itself, for us, as required.
You'll also need a text editor or an integrated development environment (IDE). If you already have a text editor that you prefer, you can probably use it. Navigate to http://dev.clojure.org/display/doc/Getting+Started for a list of environment-specific plugins to write code in Clojure. If you don't have a preference, it is suggested that you use Eclipse with Counterclockwise (http://doc.ccw-ide.org/) or Light Table (http://lighttable.com/).
Some examples in this book will also require a web browser, such as Chrome (42 or above), Firefox (38 or above), or Microsoft Internet Explorer (9 or above).