Groovy is an agile dynamic language for the Java VM.
Grails aims to bring the "coding by convention" paradigm to Groovy.

Links:

• Groovy
• Grails
• Oracle JDeveloper Plugin

Articles :

• Enhanced Calculation and Validation (Steve Muench)
  
• Groovy Scripting Tips for ADF Business Components (Steve Muench)
• Groovy and JMX : see how to manage your Java application with Groovy. with a special section on OC4J management