public Set<OrganizationalUnit> getChildren()
   {
      return ImmutableSet.copyOf(children);
   }

package com.test.domain.product;

import java.util.Collection;
import java.util.List;
import java.util.Set;

import org.springframework.util.CollectionUtils;

import com.google.common.base.Function;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;

public class OrganizationalUnitCatalog
{
   private Long id;

   private Long systemId;

   private String code;

   private Set<OrganizationalUnit> children;
   

   

   public Set<OrganizationalUnit> getChildren()
   {
      return ImmutableSet.copyOf(children);
   }

   public void setChildren(final Set<OrganizationalUnit> products)
   {
      this.children = products;
   }

   public Long getSystemId()
   {
      return systemId;
   }

   public void setSystemId(final Long systemId)
   {
      this.systemId = systemId;
   }

   public Long getId()
   {
      return id;
   }

   public void setId(final Long id)
   {
      this.id = id;
   }

   @Override
   public String toString()
   {
      return String.format("OrganizationalUnitCatalog [id=%s, systemId=%s, products=%s]", id, systemId, children.size());
   }

   public void setCode(final String code)
   {
      this.code = code;
   }

   public String getCode()
   {
      return code;
   }

   @Override
   public int hashCode()
   {
      final int prime = 31;
      int result = 1;
      result = prime * result + ((code == null) ? 0 : code.hashCode());
      result = prime * result + ((systemId == null) ? 0 : systemId.hashCode());
      return result;
   }

   @Override
   public boolean equals(final Object obj)
   {
      if (this == obj)
      {
         return true;
      }
      if (obj == null)
      {
         return false;
      }
      if (getClass() != obj.getClass())
      {
         return false;
      }
      OrganizationalUnitCatalog other = (OrganizationalUnitCatalog) obj;
      if (code == null)
      {
         if (other.code != null)
         {
            return false;
         }
      }
      else if (!code.equals(other.code))
      {
         return false;
      }
      if (systemId == null)
      {
         if (other.systemId != null)
         {
            return false;
         }
      }
      else if (!systemId.equals(other.systemId))
      {
         return false;
      }
      return true;
   }

}

<?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 package="com.test.domain.product">
   <class name="OrganizationalUnitCatalog" table="ORGANIZATIONALUNITCATALOG">
   <cache usage="read-write" />
      <id name="id" type="java.lang.Long" column="ID">
         <generator class="native">
            <param name="sequence">ORGANIZATIONALUNITCATALOG_SN</param>
         </generator>
      </id>
      <property name="systemId" type="java.lang.Long" column="SYSTEMID" not-null="true" />
      <property name="code" type="java.lang.String" column="CODE" not-null="true" />
      <set lazy="false" name="children" table="ORGANIZATIONALUNIT" cascade="all" fetch="join" >
         <cache usage="read-write" />
         <key>
            <column name="ORGANIZATIONALUNITCATALOG_ID" />
         </key>
         <one-to-many class="OrganizationalUnit" />
      </set>
   </class>
   <query name="HibernateOrganizationalUnitCatalogDao.findBySystemId">from OrganizationalUnitCatalog where systemId = :systemId</query>
</hibernate-mapping>

package com.test.domain.product;

import java.util.Collections;
import java.util.Date;
import java.util.Set;
import java.util.Stack;

import com.google.common.base.Joiner;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;


public class OrganizationalUnit
{
   public static final String QUALIFIED_NAME_SEPARATOR = "/";

   private static final Joiner JOINER = Joiner.on(QUALIFIED_NAME_SEPARATOR);

   private Long id;

   private OrganizationalUnit parent;

   private Set<OrganizationalUnit> children = Collections.emptySet();
   

   private String code;

   private String name;

   private Date startDate;

   private Date endDate;

   private boolean decisionable;

   private boolean selectable;

   private String qualifiedCode;

   
   public void addChild(final OrganizationalUnit child)
   {
      /*
       * Preconditions.checkState(systemId != null,
       * "Set the systemId before adding children. This ensures all children have the systemId when persisted.");
       */
      if (children.isEmpty())
      {
         children = Sets.newHashSet();
      }
      child.setParent(this);
      children.add(child);
   }

   
   public String getQualifiedCode()
   {
      if (qualifiedCode != null)
      {
         // use the cache
         return qualifiedCode;
      }
      if (parent == null)
      {
         qualifiedCode = code;
         return qualifiedCode;
      }

      Stack<String> s = new Stack<String>();
      OrganizationalUnit p = parent;
      while (p != null)
      {
         s.push(p.getCode());
         p = p.getParent();
      }
      qualifiedCode = JOINER.join(s) + QUALIFIED_NAME_SEPARATOR + code;

      return qualifiedCode;
   }

   public Long getId()
   {
      return id;
   }

   public void setId(final Long id)
   {
      this.id = id;
   }

   public String getCode()
   {
      return code;
   }

   public void setCode(final String code)
   {
      this.code = code;
   }

   public String getName()
   {
      return name;
   }

   public void setName(final String name)
   {
      this.name = name;
   }

   public Date getStartDate()
   {
      return startDate;
   }

   public void setStartDate(final Date startDate)
   {
      this.startDate = startDate;
   }

   public Date getEndDate()
   {
      return endDate;
   }

   public void setEndDate(final Date endDate)
   {
      this.endDate = endDate;
   }

   public boolean isDecisionable()
   {
      return decisionable;
   }

   public void setDecisionable(final boolean isDecisionable)
   {
      this.decisionable = isDecisionable;
   }

   public boolean isSelectable()
   {
      return selectable;
   }

   public void setSelectable(final boolean isSelectable)
   {
      this.selectable = isSelectable;
   }

   public OrganizationalUnit getParent()
   {
      return parent;
   }

   public void setParent(final OrganizationalUnit parent)
   {
      this.parent = parent;
   }

   public Set<OrganizationalUnit> getChildren()
   {
      return ImmutableSet.copyOf(children);
   }

   public void setChildren(final Set<OrganizationalUnit> children)
   {
      this.children = children;
   }

   public void setQualifiedCode(final String qCode)
   {
      this.qualifiedCode = qCode;
   }

   public Set<ZipCodePreferenceEntry> getBureauPreferences()
   {
      return bureauPreferences;
   }

   public void setBureauPreferences(final Set<ZipCodePreferenceEntry> bureauPreferences)
   {
      this.bureauPreferences = bureauPreferences;
   }

   @Override
   public String toString()
   {
      return String
            .format("OrganizationalUnit [getCode=%s, getQualifiedCode=%s, getName=%s, getParent=%s, getChildren=%s, getStartDate=%s, getEndDate=%s, isDecisionable=%s, isSelectable=%s, getId=%s]",
                  getCode(), getQualifiedCode(), getName(), getParent(), getChildren().size(), getStartDate(), getEndDate(),
                  isDecisionable(), isSelectable(), getId());
   }

   @Override
   public int hashCode()
   {
      final int prime = 31;
      int result = 1;
      result = prime * result + ((getQualifiedCode() == null) ? 0 : getQualifiedCode().hashCode());
      return result;
   }

   @Override
   public boolean equals(final Object obj)
   {
      if (this == obj)
      {
         return true;
      }
      if (obj == null)
      {
         return false;
      }
      if (getClass() != obj.getClass())
      {
         return false;
      }
      OrganizationalUnit other = (OrganizationalUnit) obj;
      if (getQualifiedCode() == null)
      {
         if (other.getQualifiedCode() != null)
         {
            return false;
         }
      }
      else if (!getQualifiedCode().equals(other.getQualifiedCode()))
      {
         return false;
      }
      return true;
   }
}

<?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 package="com.test.domain.product">
   <class name="OrganizationalUnit" table="ORGANIZATIONALUNIT">
      <cache usage="read-write" />
      <id name="id" type="java.lang.Long" column="ID">
         <generator class="native">
            <param name="sequence">ORGANIZATIONALUNIT_SN</param>
         </generator>
      </id>
      <many-to-one name="parent" class="OrganizationalUnit" lazy="false" column="PARENT" />
      <set name="children" lazy="false" fetch="join" table="ORGANIZATIONALUNIT" cascade="all">
         <cache usage="read-write" />
         <key>
            <column name="PARENT" />
         </key>
         <one-to-many class="OrganizationalUnit" />
      </set>      
      <property name="code" type="java.lang.String" column="CODE" not-null="true" />
      <property name="name" type="java.lang.String" column="NAME" />
      <property name="qualifiedCode" type="java.lang.String" column="QUALIFIEDCODE" />
      <property name="startDate" type="java.util.Date" column="STARTDATE" />
      <property name="endDate" type="java.util.Date" column="ENDDATE" />
      <property name="decisionable" type="boolean" column="ISDECISIONABLE" />
      <property name="selectable" type="boolean" column="ISSELECTABLE" />
   </class>
</hibernate-mapping>

package com.equifax.ic.platform.domain.product;

import java.sql.SQLException;
import java.util.List;
import java.util.Set;

import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.cfg.Environment;
import org.hibernate.dialect.HSQLDialect;
import org.junit.Before;
import org.junit.Test;
import org.springframework.orm.hibernate3.HibernateCallback;
import org.springframework.orm.hibernate3.HibernateTemplate;
import org.springframework.orm.hibernate3.HibernateTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.support.TransactionTemplate;

import com.google.common.collect.Lists;
import com.google.common.collect.Sets;

public class Test1
{
   private OrganizationalUnitCatalog catalog;

   private OrganizationalUnit mortgage;

   protected HibernateTemplate hibernateTemplate;

   protected TransactionTemplate transTemplate;

   protected PlatformTransactionManager transactionManager;

   @Before
   public void init()
   {
      catalog = new OrganizationalUnitCatalog();
      catalog.setCode("test");
      catalog.setSystemId(Long.valueOf(0));

      mortgage = new OrganizationalUnit();
      mortgage.setCode("Mortgage");
      OrganizationalUnit ml = new OrganizationalUnit();
      ml.setCode("Mortgage Loan");
      OrganizationalUnit me = new OrganizationalUnit();
      me.setCode("Home Equity LOC");

      mortgage.addChild(me);
      mortgage.addChild(ml);
      // add unit to catalog
      catalog.setChildren(Sets.newHashSet(mortgage));
   }

   @Test
   public void updateIssue()
   {
      hibernateTemplate.save(catalog);

      hibernateTemplate.execute(new HibernateCallback() {
         public Object doInHibernate(Session session) throws HibernateException, SQLException
         {
            Transaction tx = session.beginTransaction();
            Query query = session
                  .createQuery("from com.test.domain.product.OrganizationalUnitCatalog ouc where ouc.systemId=0");
            query.setMaxResults(1);
            OrganizationalUnitCatalog entity = (OrganizationalUnitCatalog) query.list().get(0);
            Set<OrganizationalUnit> children = entity.getChildren();
            System.out.println("Children count :" + children.size());

            tx.commit();

            return null;
         }
      });
   }

   @Before
   public void setUp() throws Exception
   {
      Configuration configuration = new Configuration();
      configuration.setProperty(Environment.DRIVER, getDriverClassName());
      configuration.setProperty(Environment.URL, getJdbcUrl());
      configuration.setProperty(Environment.USER, getuserName());
      configuration.setProperty(Environment.PASS, getPassword());
      configuration.setProperty(Environment.DIALECT, getHibernateDialect());
      configuration.setProperty(Environment.SHOW_SQL, "true");
      configuration.setProperty(Environment.HBM2DDL_AUTO, getHbm2DdlAuto());
      configuration.setProperty(Environment.STATEMENT_BATCH_SIZE, "5");
      configuration.setProperty(Environment.USE_SECOND_LEVEL_CACHE, "true");
      configuration.setProperty(Environment.USE_QUERY_CACHE, "true");
      configuration.setProperty(Environment.CACHE_PROVIDER, "org.hibernate.cache.EhCacheProvider");

      for (String resource : getHbmResourceUnderTest())
      {
         configuration.addResource(resource);
      }
      SessionFactory sessionFactory = configuration.buildSessionFactory();
      // OracleLobHandler lobHandler = new OracleLobHandler();
      // lobHandler.setNativeJdbcExtractor(new SimpleNativeJdbcExtractor());
      //
      // ((LocalSessionFactoryBean) sessionFactory).setLobHandler(lobHandler);

      transactionManager = new HibernateTransactionManager(sessionFactory);
      hibernateTemplate = new HibernateTemplate(sessionFactory);
      transTemplate = new TransactionTemplate(transactionManager);
   }

   protected String getHbm2DdlAuto()
   {
      return "create-drop";
   }

   protected String getPassword()
   {
      return "";
   }

   protected String getHibernateDialect()
   {
      return HSQLDialect.class.getName();
   }

   protected String getuserName()
   {
      return "sa";
   }

   protected String getJdbcUrl()
   {
      return "jdbc:hsqldb:mem:test";
   }

   protected String getDriverClassName()
   {
      return "org.hsqldb.jdbcDriver";
   }

   public List<String> getHbmResourceUnderTest()
   {
      return Lists
            .newArrayList("com/test/domain/OrganizationalUnit.hbm.xml", "com/test/domain/OrganizationalUnitCatalog.hbm.xml");
   }
}

Hibernate: insert into ORGANIZATIONALUNITCATALOG (ID, SYSTEMID, CODE) values (null, ?, ?)
Hibernate: call identity()
Hibernate: insert into ORGANIZATIONALUNIT (ID, PARENT, CODE, NAME, QUALIFIEDCODE, STARTDATE, ENDDATE, ISDECISIONABLE, ISSELECTABLE) values (null, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate: call identity()
Hibernate: insert into ORGANIZATIONALUNIT (ID, PARENT, CODE, NAME, QUALIFIEDCODE, STARTDATE, ENDDATE, ISDECISIONABLE, ISSELECTABLE) values (null, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate: call identity()
Hibernate: insert into ORGANIZATIONALUNIT (ID, PARENT, CODE, NAME, QUALIFIEDCODE, STARTDATE, ENDDATE, ISDECISIONABLE, ISSELECTABLE) values (null, ?, ?, ?, ?, ?, ?, ?, ?)
Hibernate: call identity()
Hibernate: update ORGANIZATIONALUNIT set ORGANIZATIONALUNITCATALOG_ID=? where ID=?
Hibernate: update ORGANIZATIONALUNIT set PARENT=? where ID=?
Hibernate: update ORGANIZATIONALUNIT set PARENT=? where ID=?
Hibernate: select top ? organizati0_.ID as ID1_, organizati0_.SYSTEMID as SYSTEMID1_, organizati0_.CODE as CODE1_ from ORGANIZATIONALUNITCATALOG organizati0_ where organizati0_.SYSTEMID=0
Hibernate: select children0_.ORGANIZATIONALUNITCATALOG_ID as ORGANIZ10_1_, children0_.ID as ID1_, children0_.ID as ID0_0_, children0_.PARENT as PARENT0_0_, children0_.CODE as CODE0_0_, children0_.NAME as NAME0_0_, children0_.QUALIFIEDCODE as QUALIFIE5_0_0_, children0_.STARTDATE as STARTDATE0_0_, children0_.ENDDATE as ENDDATE0_0_, children0_.ISDECISIONABLE as ISDECISI8_0_0_, children0_.ISSELECTABLE as ISSELECT9_0_0_ from ORGANIZATIONALUNIT children0_ where children0_.ORGANIZATIONALUNITCATALOG_ID=?
Hibernate: select children0_.PARENT as PARENT1_, children0_.ID as ID1_, children0_.ID as ID0_0_, children0_.PARENT as PARENT0_0_, children0_.CODE as CODE0_0_, children0_.NAME as NAME0_0_, children0_.QUALIFIEDCODE as QUALIFIE5_0_0_, children0_.STARTDATE as STARTDATE0_0_, children0_.ENDDATE as ENDDATE0_0_, children0_.ISDECISIONABLE as ISDECISI8_0_0_, children0_.ISSELECTABLE as ISSELECT9_0_0_ from ORGANIZATIONALUNIT children0_ where children0_.PARENT=?
Hibernate: select children0_.PARENT as PARENT1_, children0_.ID as ID1_, children0_.ID as ID0_0_, children0_.PARENT as PARENT0_0_, children0_.CODE as CODE0_0_, children0_.NAME as NAME0_0_, children0_.QUALIFIEDCODE as QUALIFIE5_0_0_, children0_.STARTDATE as STARTDATE0_0_, children0_.ENDDATE as ENDDATE0_0_, children0_.ISDECISIONABLE as ISDECISI8_0_0_, children0_.ISSELECTABLE as ISSELECT9_0_0_ from ORGANIZATIONALUNIT children0_ where children0_.PARENT=?

Hibernate: select children0_.PARENT as PARENT1_, children0_.ID as ID1_, children0_.ID as ID0_0_, children0_.PARENT as PARENT0_0_, children0_.CODE as CODE0_0_, children0_.NAME as NAME0_0_, children0_.QUALIFIEDCODE as QUALIFIE5_0_0_, children0_.STARTDATE as STARTDATE0_0_, children0_.ENDDATE as ENDDATE0_0_, children0_.ISDECISIONABLE as ISDECISI8_0_0_, children0_.ISSELECTABLE as ISSELECT9_0_0_ from ORGANIZATIONALUNIT children0_ where children0_.PARENT=?
Children count :1
Hibernate: update ORGANIZATIONALUNIT set ORGANIZATIONALUNITCATALOG_ID=null where ORGANIZATIONALUNITCATALOG_ID=?
Hibernate: update ORGANIZATIONALUNIT set PARENT=null where PARENT=?
Hibernate: update ORGANIZATIONALUNIT set ORGANIZATIONALUNITCATALOG_ID=? where ID=?
Hibernate: update ORGANIZATIONALUNIT set PARENT=? where ID=?
Hibernate: update ORGANIZATIONALUNIT set PARENT=? where ID=?
Hibernate: update ORGANIZATIONALUNIT set ORGANIZATIONALUNITCATALOG_ID=null where ORGANIZATIONALUNITCATALOG_ID=?
Hibernate: update ORGANIZATIONALUNIT set PARENT=null where PARENT=?
Hibernate: update ORGANIZATIONALUNIT set ORGANIZATIONALUNITCATALOG_ID=? where ID=?
Hibernate: update ORGANIZATIONALUNIT set PARENT=? where ID=?
Hibernate: update ORGANIZATIONALUNIT set PARENT=? where ID=?