JavaServer Pages (JSP) is a technology that lets you embed Java code inside HTML pages. This code can be inserted by means of <% %> blocks or by means of JSTL tags. To insert Java code into JSP, JSTL tags are generally preferred, since tags adapt better to their own tag representation of HTML, making JSP pages look more readable.

JSTL is just a standard tag library provided by Oracle. We can add a reference to the JSTL tag library in our JSP pages as follows:

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%> 

Similarly, Spring MVC also provides its own tag library to develop Spring JSP views easily and effectively. These tags provide a lot of useful common functionality such as form binding, evaluating errors, and outputting messages, and more when we work with Spring MVC.

In order to use these, Spring MVC has provided tags in our JSP pages. We must add a reference to that tag library in our JSP pages as follows:

<%@taglib prefix="form" uri="http://www.springframework.org/tags/form" %> 
<%@taglib prefix="spring" uri="http://www.springframework.org/tags" %> 

These taglib directives declare that our JSP page uses a set of custom tags related to Spring and identify the location of the library. They also provide a means to identify custom tags in our JSP page. In the taglib directive, the uri attribute value resolves to a location that the servlet container understands and the prefix attribute announces which bits of markup are custom actions.