Difference between GET and POST ?
The difference between a GET and a POST is the way data is transferred to a servlet. With a GET, the URL will show each name/value pair on the query string in the URL. For example, if you had a form with a field named 'para1,' and when submitted had a value of 'paraValue,' the url might be something like this:
With a POST, this information is not visible in the URL. Instead, it is transferred in the HTTP headers.
The method used in the Servlet for processing either a GET or a POST is different too. If you use a GET, the method that is called is doGet(HttpServletRequest, HttpServletResponse). The doGet method is also called if there is no GET or POST data. If you use a POST, the method called is doPost(HttpServletRequest, HttpServletResponse).
Check this link for summarized comparison.