looks like BV_SessionID is same as we have jsessionid.
My question is can we replece the "jsessionid" with and value
what could be the significance of BV_EngineID ..is it some thing related to multiple servers and distributed engines that serve the request .
The jsessionid is not a variable - it's an appendage. If you'll notice, there's a ";" between it and the rest of the URL, including the request variables, which are inrtoduced by the "?".
As far as I can remember without checking, it's stripped off before any of the HttpServletRequest methods can ever even see it.
There's no point in mucking around with it. All it - or any J2EE session IDs - really is is a handle by which the server can match the session with a given client. There's no formal spec about what that ID should be, how it should be formed, of even if the same ID should be passed on each request/response cycle. jsessionid hacks that work on one server may not work on another. Or even a different version or configuration of the same server.
An IDE is no substitute for an Intelligent Developer.