what is the different between the method of session.Dispose() and session.Close()?
is there necessary to set the null value to the session after dispose is?

AFAIK, session.Dispose() and session.Close() do almost the same thing... (you can read their code :wink: )

And you only need to set the null value to the session if you want to be sure that it gets collected by the GC at the next collect... But I don't think it is very important for classic applications...