I am using the following open source classes and trying to connect them using hibernate. I am getting the following exception :

Caused by: org.hibernate.MappingException: Could not determine type for: mod.sun.security.acl.AclEntryImpl, for columns: [org.hibernate.mapping.Column(aclentry)]
at org.hibernate.mapping.SimpleValue.getType(SimpleValue.java:265)
at org.hibernate.mapping.SimpleValue.isValid(SimpleValue.java:252)
at org.hibernate.mapping.Collection.validate(Collection.java:247)
at org.hibernate.mapping.IndexedCollection.validate(IndexedCollection.java:67)
at org.hibernate.cfg.Configuration.validate(Configuration.java:841)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1000)
at com.belfast.hibernate.HibernatePlugin.<clinit>(HibernatePlugin.java:34)


The code is as follows:

package mod.sun.security.acl;

import java.security.Principal;
import java.security.acl.AclEntry;
import java.security.acl.Group;
import java.security.acl.Permission;
import java.util.Enumeration;
import java.util.Vector;

/**
* This is a class that describes one entry that associates users
* or groups with permissions in the ACL.
* The entry may be used as a way of granting or denying permissions.
* @author Satish Dharmaraj
*/
public class AclEntryImpl implements AclEntry {

private long aclentryid;
private Principal user = null;
private Vector<Permission> permissionSet = new Vector<Permission>(10, 10);
private boolean negative = false;


=====================================================================


package mod.sun.security.acl;

import java.security.Principal;
import java.security.acl.Acl;
import java.security.acl.AclEntry;
import java.security.acl.Group;
import java.security.acl.NotOwnerException;
import java.security.acl.Permission;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.NoSuchElementException;
import java.util.Vector;

import com.belfast.storage.object.ObjectData;

/**
* An Access Control List (ACL) is encapsulated by this class.
* @author Satish Dharmaraj
*/
public class AclImpl extends OwnerImpl implements Acl {
//
// Maintain four tables. one each for positive and negative
// ACLs. One each depending on whether the entity is a group
// or principal.
//

private long aclid;

private Hashtable<Principal, AclEntry> allowedUsersTable =
new Hashtable<Principal, AclEntry>(23);
private Hashtable<Principal, AclEntry> allowedGroupsTable =
new Hashtable<Principal, AclEntry>(23);
private Hashtable<Principal, AclEntry> deniedUsersTable =
new Hashtable<Principal, AclEntry>(23);
private Hashtable<Principal, AclEntry> deniedGroupsTable =
new Hashtable<Principal, AclEntry>(23);
private String aclName = null;
private Vector<Permission> zeroSet = new Vector<Permission>(1,1);
private ObjectData object;

==================================================

<?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="mod.sun.security.acl">
<class name="AclImpl" table="BEACL">
<id name="aclid">
<generator class="native"></generator>
</id>
<map name="allowedUsersTable" table="beaclentry">
<key column="id"></key>
<index column="principal" type="com.belfast.db.object.Alias"></index>
<element column="aclentry" type="mod.sun.security.acl.AclEntryImpl"></element>
</map>
<map name="allowedGroupsTable" table="beaclentry">
<key column="id"></key>
<index column="principal" type="mod.sun.security.acl.GroupImpl"></index>
<element column="aclentry" type="mod.sun.security.acl.AclEntryImpl"></element>
</map>
<map name="deniedUsersTable" table="beaclentry">
<key column="id"></key>
<index column="principal" type="com.belfast.db.object.Alias"></index>
<element column="aclentry" type="mod.sun.security.acl.AclEntryImpl"></element>
</map>
<map name="deniedGroupsTable" table="beaclentry">
<key column="id"></key>
<index column="principal" type="mod.sun.security.acl.GroupImpl"></index>
<element column="aclentry" type="mod.sun.security.acl.AclEntryImpl"></element>
</map>
<property name="aclName"></property>
<list name="zeroSet" inverse="false" cascade="all" table="beperm">
<key column="permid"/>
<index column="permission"></index>
<one-to-many class="mod.sun.security.acl.PermissionImpl"></one-to-many>
</list>
<many-to-one name="object" class="com.belfast.storage.object.ObjectData" column="objectid" not-null="true"/>
</class>
</hibernate-mapping>

Any help is appreciated.