When updating your application to grails 2.x from the 1.3.x branches, you might notice that your logging no longer works.
This is due to changes in the logging by convention. While this is mentioned in the user guide (under Logging By Convention Changes), it is not very clear what this means.
In our update, we found that we needed to change our Log4J configuration from:
info 'grails.app.controller', 'grails.app.task', 'grails.app.service', 'grails.app.tagLib', 'grails.app.bootstrap.BootStrap'
info 'grails.app.controllers', 'grails.app.jobs', 'grails.app.services', 'grails.app.taglib', 'grails.app.conf.BootStrap'
While this might look trivial, it’s a fairly important breaking change.
Additionally, if you have Quartz jobs in your application, the logging convention changes from task to jobs. This is not mentioned in the grails documentation.