Procyon

Free Procyon books, articles, documentation

Gradle

• Building Java Projects with Gradle
• Gradle Succinctly - José Roberto Olivas Mendoza
• Gradle User Guide - Hans Dockter, Adam Murdoch (PDF) (CC BY-NC-SA)

Grails

• Getting Started with Grails
• Grails Tutorial for Beginners - grails.asia (:card_file_box: archived)
• The Grails Framework - Reference Documentation - Graeme Rocher, Peter Ledbrook, Marc Palmer, Jeff Brown, Luke Daley, Burt Beckwith, Lari Hotari (PDF)

Spock Framework

• Spock Framework Reference Documentation - Peter Niederwieser

Search on GitHub