what is the difference between MVC1 and MVC2

It might be possible that you read this version in connection with asp.net MVC, as there different versions of that framework. There is no version 2.0 of the mvc pattern, just a version 2.0 of the asp.net MVC framework.

In context of jsp servlets see: Model 1 and Model 2. In a nutshell: Model 1 doesn't have a controller to dispatch requests, Model 2 does.

In MVC 1, controller and model,both are JSP. While in MVC2 controller is servlet and model is java class. In MVC1 there is tight coupling between page and model as data access is usually done using Custom tag or through java bean call.
In MVC2 architecture there is only one controller which receives all the request for the application and is responsible for taking appropriate action in response to each request.