i am working on multi user web application which has technology stack like vaadin 6.7, web sphere portal server 8 and springs.
When multiple user login (different machines with different login ) at the same time.I noticed all the user generating the same http session id (httpservletrequest.getSession()) for all the three request because of which session parameter got replaced. i did some research and find out vaadin 6 has some problem related to providing single instance of vaddinApplication instead of providing the new instance for new user but to tackle this problem. We also implement thread local to tackle this problem. Can any one provide me a theory why because of singleton instance of vaadinApplication i am getting the same session. May be old session replaced with the new one but i am not sure regarding this theory.