From the Programming Groovy book webpage:
Groovy brings you the best of both worlds: a flexible, highly productive, agile, dynamic language that runs on the rich framework of the Java Platform. Groovy preserves the Java semantics and extends the JDK to give you true dynamic language capabilities⎯programming in Groovy feels like you’re using an augmented Java. Programming Groovy will help you learn and take advantage of the latest version of this rich dynamic language, so you can be a more productive Java Platform developer.From the Groovy Recipes book webpage:
If you’re a busy Java professional who needs quick solutions to everyday problems, then Groovy Recipes is for you. The Groovy language and Grails web framework give you seamless integration with your legacy Java code while adding the flexibility and dynamism of a scripting language and giving you modern, agile, time-saving techniques. Groovy allows you to write code the way you always thought you should—you’ll never look at Java the same way again.For those who like Ruby and Rails and the ability to access other Java frameworks and APIs, but also really want their Java-like syntax (and hence more than just JRuby), these are the books to read. Groovy even has its own answer to Rails called "Grails"
- An Introduction to Groovy and Grails
- Groovy with Grails – Java’s fight back to Ruby on Rails
- Groovy Zone | Everything for the Groovy & Grails developer
- Mastering Grails : Read more in this series to gain a further understanding of Grails and all you can do with it.
- Groovy homepage
- Grails homepage
- Grails Framework Reference Documentation: The Grails bible.
- Practically Groovy : This developerWorks series is dedicated to exploring the practical uses of Groovy and teaching you when and how to apply them successfully.
- Grails Plugins: Documentation for all Grails plug-ins.