I have a form generated by servlet1 (by calling http://servlet/servlet1) and on submitting this form another servlet, servlet2 is called through "https" protocol. In the servlet2, the request object is found to be null disabling me to collect parameters passed from the servlet1 form.
Are you sure your setup is correct. There is a lot more the "HTTPS" then writting it in a URL. You can handle "HTTPS" many different ways. You can do it in your code, web.xml, and/or web server or servlet engine.
If your SSL and HTTPS are setup correctly make sure that your calling servlet is using the same protocol as your request handling servlet.
Servlet1 -[HTTPS]-> HTML FORM1 -[HTTPS]-> Servlet2
Servlet1 -[HTTP]-> HTML FORM1 -[HTTPS]-> Servlet2
This is because https and http use different ports, so if you switch the ports in mid request, you'll have servlet1 writting to a different port than the one servlet2 is reading from.