Doing more Groovy on Grails dev today and have really got in to the Grails Console. What this allows you to do is to fire up a console from within the context of your application and then dick about with code snippets. The context bit is important as you can run all the data access stuff just as you would in you application. In the above example I list the contents of the JadLine table.
The real benefit for me, particularly when on a leaning curve of a new language, is the ability to run a code snippets with out having to arse about in browsers. This really chops the corner off the usual code, reload and grumble process of web development in Java.
To run the Grails console, cd to you project directory and enter “Grails console”