Hi
I have two classes named college and student with parent child relationship .
the mapping file is as fallows.

<hibernate-mapping>
<class name="com.sample.College" table="College">
<id name="dbid" column="College_id" type="long">
<generator class="increment" />
</id>
<list name="studentList" table="College_Student" lazy="true" >
<key column="dbid"/>
<index column="rmxcamp_number"/>
<many-to-many class="com.sample.Student" column="college_studid"/>
</list>
</class>
</hibernate-mapping>

and code to CREATE, ADD and GETting records are as fallows

CREATE: in a HTTP Request - Response model
ex:
public long createCollege(String name,String city){
Session hibernatesession =hibernateSessionFactory.getCurrentSession();
Transaction ts=hibernatesession.beginTransaction();
College c1=new College(name,city); // here empty student list is created
hibernatesession.save(c1);
ts.commit();
httpsession.setAttribute(c1.getDbid(),c1);
return c1.getDbid();
}
here c1 is placed in the HTTP session with dbid, to get that object in subsequent request

ADD: in a HTTP Request - Response model

public void addStudent(long dbid, String stundentname, float marks){
College c1=(College)httpsession.getAttribute(dbid());
Session hibernatesession =hibernateSessionFactory.getCurrentSession();
Transaction ts=hibernatesession.beginTransaction();
Student s1=new Student(studentname,marks);
c1.addStudent(s1); // s1 is added to list of student;
hibernatesession.save(s1);
hibernatesession.update(c1);
ts.commit();
}

GETting objects : in a HTTP Request - Response model


public List<Student> getStudents(long dbid){
List<Student> studlist=null;
College c1=(College)httpsession.getAttribute(dbid());
Session hibernatesession =hibernateSessionFactory.getCurrentSession();
Transaction ts=hibernatesession.beginTransaction();
studlist=c1.getStudentList();
// displaying the list values giving LazyInitialation exception here.
ts.commit();
}

the exception is as fallows"

98430 [btpool0-0] ERROR org.hibernate.LazyInitializationException - failed to lazily initialize a collection of role: com.sample.College.studentList, no session or session was closed
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.sample.College.studentList, no session or session was closed
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:380)
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:372)
at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:365)
at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:108)
at org.hibernate.collection.PersistentList.toString(PersistentList.java:395)
at com.sample.College.getStudentList(UserServiceUtil.java:600)

I think, the college object is detached from the hibernate session,it is attached to the previous hibernate session
but it is not working even i merged it to the new hibernate session as fallows or with get() method.
ex:

c1= (College)hibernatesession.merge(c1);
or
c1 =(College)hibernateSession.get(College.class,c1.getDbid());

it is giving the same above exception.


Please Help me on this.
How to lazy load a collection in a request -response model


thanks
ramanaiah a v