I was doing experiment with Hibernate self referential interigity and created following structure in hbm file and database side.
Database script:
################################################################
CREATE TABLE CATEGORY
(
CATID INTEGER NOT NULL,
CATNAME VARCHAR2(255 BYTE) NOT NULL,
PARENTID INTEGER DEFAULT 0
)
ALTER TABLE CATEGORY ADD (
CONSTRAINT FK_CATEGORY FOREIGN KEY (PARENTID)
REFERENCES CATEGORY (CATID));
########################################################
Hbm File
#######################################################
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.abhi.test.hibernate.dto.CategoryDTO" table="CATEGORY">
<id name="catId" type="int" column="CATID">
<generator class="assigned" />
</id>
<property name="catName" column="CATNAME" type="java.lang.String" />
<one-to-one name="parentCategory" />
<set name="childCategories"
table="CATEGORY"
inverse="true"
lazy="true"
>
<key column="PARENTID"/>
<many-to-many class="com.abhi.test.hibernate.dto.CategoryDTO" column="CATID" />
</set>
</class>
</hibernate-mapping>
######################################################################
Java Code:
###################################################################
public static void main(
String[] args) {
Session session = HibernateUtil.currentSession();
Transaction transaction = session.beginTransaction();
try{
Query query =session.createQuery("From com.abhi.test.hibernate.dto.CategoryDTO");
System.out.println(query.getQueryString());
List list = query.list();
System.out.println(list.size());
for(Iterator i=list.iterator();i.hasNext()
{
CategoryDTO categoryDTO = (CategoryDTO)i.next();
System.out.println("Child Categories----"+categoryDTO.getChildCategories());
System.out.println(categoryDTO.getParentCategory().getParentCategory().getParentCategory().getCatId());
}
transaction.commit();
}catch (Exception e) {
// transaction.rollback();
e.printStackTrace();
}
session.close();
}
##################################################
In above java code it is creating infinite CategoryDTO object struture but it is working fine without giving any memory problem.
Anyone please suggest what is happening over here or am i doing something wrong.
