Whenever I am trying to put logged in user in to HttpSession it throws exception like...
com.google.gwt.user.client.rpc.SerializationException: Type 'org.hibernate.collection.PersistentBag' was not assignable to 'com.google.gwt.user.client.rpc.IsSerializable' and did not have a custom field serializer. For security purposes, this type will not be serialized.
Even its comfortable to use Hibernate along with GWT with only one set of beans. To do this, you need create one converter which will remove all the uninitialized proxies from beans before beans are transfered from the server to client. In this approach, before sending beans back to the client(Browser), you need to send the beans to Conversion layer.
I have used GWT with hibernate. But I have not used any other external jar. I have my POJO implement the Serializable interface and its the same object that is being used on the gwt client as well as hibernate.. I haven't used any convertor as well though it might be a better way as you don't want to share the same pojo between the client and the server.
There is a possibility that you have a class which implements Serializable and you have an attribute field within that class which is not Serializable hence you might be getting this exception.
Thanks and Regards,
I remember reading documentation that said GWT will treat Java Serializable identically to GWT IsSerializable. In other words, if you have a bunch of existing Java classes that implement Serializable, you don't need to go back and add IsSerializable to them.