 <p>Unfortunately that page is quite dated and not correct for Grails 3+.</p> <p>You can find <code>BootStrap.groovy</code> under <code>grails-app/init</code>, and the settings that were specified in <code>DataSource.groovy</code> are now with the rest of the config settings in <code>application.yml</code> (or <code>application.groovy</code> if you create it).</p>