Grails Get/Use Http Session In Service Or Util Class

import org.codehaus.groovy.grails.web.util.WebUtils
import javax.servlet.http.HttpSession

HttpSession httpSession = WebUtils.retrieveGrailsWebRequest().request.session

Grails access HttpSession from service or from other src files

import org.springframework.web.context.request.RequestContextHolder; 

HttpSession session = RequestContextHolder.currentRequestAttributes().getSession();

##### 
/* Code */
session.properties.each {
    println it;
}

/* Output from above code */
creationTime=1387331940863
maxInactiveInterval=1800
sessionContext=org.apache.catalina.session.StandardSessionContext@1ff04376
attributeNames=java.util.Collections$2@2aec16fa
class=class org.codehaus.groovy.grails.web.servlet.mvc.GrailsHttpSession
servletContext=org.apache.catalina.core.ApplicationContextFacade@3dc6e9f8
new=false
id=A2791167D1EC3D21025078895357147D
valueNames=[Ljava.lang.String;@71d88d19
lastAccessedTime=1387332146960

#####
/* Code */
session.attributeNames.each {
    println it;
}

/* Output from above code */
SETTING
org.codehaus.groovy.grails.FLASH_SCOPE
USER

#####
/* Code */
session.attributeNames.each {
    println session.getAttribute(it.toString());
}

/* Output from above code */
[paginationCount:10, generateClientID:On]
[:]
[name:Admin, id:1, username:admin, isSystemAdmin:true]