You can not use instanceof operator on Hibernate Proxy even if the proxy is initialised.You should use Visitor in that case .For example

There is charity fund which accepts donation from Party (it may be Group also).After receiving donation it would send thank mail to Party or in case of Group ,it sends thanks mail to everyone in group.


@Entity
//set inheritance type
public class Party {
private String name;
public String getName() {
return name;
}
}
@Entity
public class Group extends Party {
List getGroupMembers() {
return groupMembers;
}
}

@Entity
public class Donation {
//fetchType is set to lazy
private Party;
public Party getParty {
return Party;
}
}


Now lets see charity Service --

public class CharityService {
public void sendThanksMailToParty(Donation donation){
Party party = donation.getParty();
//instaneof operator would alsways return false ,even if
//Party is really Group
//because Proxy is subclass of Party, it does not know about Group
//Proxy has a target and it delegates method calls to it.
if(party instanceOf Group){
//send email to every group member
}
}
}


so how to make it work ,lets use vistor pattern



public interface Visitable {
public void accept(Visitor visitor);
}
public interface Visitor {
public void visit(Party party);
public void visit(Group group);
}

public class DefaultVisitor extends Visitor {
public void visit(Party party){};
public void visit(Group group){};
}

@Entity
//set inheritance type
public class Party implements Visitable{
private String name;
public String getName() {
return name;
}
public void accept(Visitor visitor){
visitor.visit(this);
}
}

@Entity
public class Group extends Party implements Visitable{
List getGroupMembers() {
return groupMembers;
}
public void accept(Visitor visitor){
visitor.visit(this);
}
}



Now lets see charity service again ---

Now lets see charity Service again --

public class CharityService {
public void sendThanksMailToParty(Donation donation){
Party party = donation.getParty();
party.accept(new DefaultVisitor(){
public void visit(Group group){
List parties= group.getGroupMembers;
//now send email to each member of party
}
});
}
}


Read more: http://feeds.dzone.com/~r/dzone/snippets/~3/u7kci8XGrM8/11555