title: How to import Authentication and SecurityContextHolder in grails
body: <p>I want to logout manually and I use <a href="https://stackoverflow.com/questions/7788487/grails-redirect-post-logout-using-spring-security-core-3-0-6">Grails Redirect Post-Logout Using spring-security-core-3.0.6+</a> to resolve my issues but there is an error of "Unable to resolve Authentication" so can anyone help me how to import Authentication and SecurityContextHolder in grails?</p>