Bhoopendra Singh

Functions can be override but instance variables. So dynamic method dispatch call is applicable to methods only. In your case p.x will always call instance variable of class p.

Since this is a derived value, why do you want store?
In case you want to do without any synchronization , you can do in two steps. First insert records and than update column with derived value. I am assuming pkid is id for new records and you don't need to get this value as max(..).

Since session is specific to single user, storing signed in user details in session will not work. You need to store signed in users details in location which accessible from all live session. One of the option is application context. Other maybe some some external persistent storage.
Also, since this is a web based application, which approach is being used "Pull" or "Push" to show incoming chat message?

Matthew is correct. You overriding default behaviour of Thread's Run method. So this method is doing what you are asking to do.