What are the differences between the getAttribute() and the getParameter() methods in HttpServletRequest?
getParameter() returns http request parameters. These are passed from the client to the server. For example http://example.com/servlet?parameter=1. They can only return String.
getAttribute() is for server-side usage only - you fill the request with attributes that you can use within the same request. For example - you set an attribute in a Servlet and read it from a JSP. These can be used for any object, not just string.