how to get session object in simple java class??

i am fallowing a simple mvc architecture.

actually my problem is....

i am using 4 classes in my work.

1) GroupDetails.jsp

2) GroupPojo.java (simple pojo class which have setters and getters)

3) GroupServlet.java (a servlet class for control)

4) GroupDetailsDao.java (it is also a simple java class which have the jdbc logic)

in JSP : accepting the groupid and groupname from the user. and i am setting the value to GroupPojo.java and set this pojo object into session. sending control to servlet.

in servlet : here i am checking that whether jsp want to insert data or update data or delete the data. base on the jsp request i am calling paticular method in the GroupDetailsDao.java only.

problem......................... is....................

now i need to get that session object (GroupPojo) into GroupDetailsDao.java and i need to perform some operations and finally i need set that grouid and groupname to GroupPojo.java and set this GroupPojo object into session.

so, please tell me, how to get the session object (GroupPojo) in a simple java class (GroupDetailsDao.java)

please help me....