request.getSession() and request.getSession(true).... Both are same.
By default request.getSession()'s argument is true....... it means that when we get request.getSession() then if session object is exists then it is returned otherwise new one is created but in case of request.getSession(false) if we try to get session object using request.getSession(false) then if session object is exists then it is returned other wise null is returned.