How to use other servlets service in another servlet?

I need to forward/craft request to another servlet from other servlet's service method manually. This servlet which calls another servlet, should extract the data from other servlet's response and send it's own response to client. How to achieve this kind of functionality?

Client <-----> Servlet1 <-----> Servlet2

I know it's bad design, but due the circumstances we have to introduce the functionality of Servlet2 to Servlet1