IntelliJ's IDEA Java/Groovy/Ruby/PHP/etc. IDE is considered by many to be the best IDE for Java/Groovy, there is a free version.

• Download and install IntelliJ's IDEA v9.0+ CE from here.


• Download the latest AribaWeb plugin for IDEA here.
  
  
  
  • md aribaweb\lib in IDEA's plugin directory
  
  
  • copy or move the plugin JAR into the above directory

• Create a new AribaWeb project i.e. type aw and follow the prompts (e.g. see this video)


• Launch IDEA at the end i.e. MyFirstApp.ipr
  
  
  • You'll be prompted to tell IDEA where AribaWeb lives
  
  
  • Point it to wherever you installed AiribaWeb
  
  
  • Adjust the Ant version to be used for your project after watching this video
  
  
  • You can adjust the JDK used by IDEA for your project under File | Project Structure | Project (aka General Settings for Project 'Whatever')

• BTW, there's a little more info. here, including how to install the Eclipse plugin