History

New features and improvements in Groovy 1.7:

• Anonymous Inner Classes and Nested Static Classes
• Annotation enhancements
• Grape enhancements
• Power Asserts
• AST enhancements: AST Viewer and AST Builder
• Ability to customize the Groovy Truth
• Dependency upgrades
• Rewrite of GroovyScriptEngine
• GroovyConsole enhancements
• SQL batch updates and transactions
• More details: (draft) Groovy 1.7 release

New features and improvements in Groovy 1.6:

• Great runtime performance improvements
• Multiple assignments- optional return in if/else and try/catch blocks
• AST transformations and all the provided transformation annotations like @Singleton, @Lazy, @Immutable, @Delegate and friends
• The Grape module and dependency system and its @Grab transformation
• Various Swing builder improvements, thanks to the Swing / Griffon (http://griffon.codehaus.org) team
• As well as several Swing console improvements
• The integration of JMX builder
• JSR-223 scripting engine built-in
• Various metaprogramming improvements, like the EMC DSL, per-instance metaclasses even for POJOs, and runtime mixins
• More details: Infoq

New features and improvements in Groovy 1.5:

• Integrates Java 5 features: annotations, generics, static imports and enums
• New meta-programming capabilities
• A few syntax enhancements have also found their way into it to help ease the development of Domain-Specific Languages
• Groovy's Swing builder support, to help you build Swing UIs, has almost completely been rewritten and spiced up with several useful additions
• A great attention to performance improvements made this new version much
• A joint Java / Groovy compiler to let you mix and match Groovy and Java classes in the same compilation step
• A GroovyDoc equivalent to JavaDoc lets you document your Groovy classes
• A rewritten interactive shell is now really interactive and provides useful command completions for making you more productive
• The Groovy Swing console has also been improved
• More details: Infoq