cookie

Cookie, sometimes using the plural form of Cookies, that certain websites in order to identify the user, the session tracking and stored in the user's local terminal data (usually encrypted). Defined in RFC2109 (obsolete), the latest specification is replaced by RFC2965.
Initiated
Cookie was originally a former employee of Lou Montulli Netscape in March 1993 of the invention.
Cookie is generated by the server, sent to the User-Agent (typically a browser), the browser will be Cookie's key / value saved to a text file in a directory, the next request to send the same site to Cookie server (provided your browser settings to enable cookie). Cookie name and value can be defined by the server-side to develop their own, for the JSP can also be written in terms jsessionid, so that the server can know whether the user is the legitimate user and the need to re-login and so on.