Generated code in Grails used to use an @Property annotation to indicate Grails properties. This was used somewhere around version 0.1 – 0.2, was still supported in 0.3.1 (although I think not used in newly generated code), but is now no longer in 0.4.2. You’ll see the error:
<code> @ line 8, column 6.ExampleController: 34: unable to resolve class Property unable to find class for annotation </code>
Just go through your old code if you have migrated from prior versions of Grails and replace the @Property annotation with def instead – the code will work with 0.4.2+.