how to show new form in the same web page?

Im new at java web programming. Can anyone can give me idea or link how to do these kind of effect in web application. see the picture i attached.

http://ift.tt/1TP2rjQ

when i click the plus sign it will show these form in the same web page

http://ift.tt/1g3gGTT

How to do these in servlet ? Any help will be appreciated.