uses of sessions & cookies?

Question

what is use of sessions & cookies in servlets?

Answer 1

Session store items between HTTP requests.

Cookies are used to keep track of sessions by making the browser hold and return a unique ID (the cookie) that is used to recall the stored session on the next HTTP request.

Answer 2

A brief read http://www.apl.jhu.edu/~hall/java/Servlet-Tutorial/Servlet-Tutorial-Session-Tracking.html