No form parameters are passed when submitting a form

The problem once identified was so stupid and obvious that for while I felt bad. I should have found it very quickly. Anyway, so what was happening is, I created a login for my new web application and after integrating with Spring security I was not able to login. I changed the log level of Spring security package to TRACE and then found that username and password are passed as empty strings.
Then I checked the request sent from browser and noticed that browser is not sending the params with the request.
Below is my html code of the login form:



I spent some time to figure out what is happening but it was already past midnight so I left it like that and slept.
In morning I looked into the code again and very quickly noticed that the input elements in the html does not have "name" attribute. Ooops !!! Very stupid mistake done by someone who has created many web applications.

But it shows that sometimes simple mistakes like this are hard to find.

~Manish

Why should we allow only single session per user?

Some time back me , Mishra and Mittal were discussing some technical issues and then Mishra mentioned that he had a requirement to implement this feature to allow only one session per user. He implemented this without any problem but then we started thinking what are the possible reasons for which people want to implement this requirement. After some thinking, discussing and googling we could come with below reasons:

1. Security. If we allow only one session per user then on creation of second session we can alert the user that there is already a active session and allow a way to kill the previous session. This way if the user is unaware of previous session then this will serve as a warning that his/her credentials may have been compromised. And user can change his credentials.
2. Licensing. Some products are priced as per number of users using the product. So, avoiding the multiple session per user will prevent the misuse of the license.
3. Product Implementation. This is very specific to the product requirement. If the application maintains some kind of user's working state then multiple sessions can mess it up.

 I will update this post if I could find some more reasons.

~Manish