"The main message I'm going home with is the rather obvious realisation that Groovy is in a completely different category to any other scripting language, because of its relationship with Java. Hence, lots of stuff (such as the Java debugger, as indicated above) can simply be reused when working with Groovy. That insight should also inform the tooling provided for Groovy." - Geertjan at the Grails eXchange
This is a great quote from Geertjan from Sun and highlights what we've been saying about Groovy for years: Java integration is more than being able to invoke a method on a Java class, it is object model integration, tools integration, debugger integration, profiling integration etc. etc. etc.