Don't Repeat Yourself, also known as the DRY principle, is a philosophy that reduces development time and increases the efficiency of a team working on a web application. Scripting languages such as PHP, Ruby based RoR, and so on, have this idea as part of their core architectural design. But for compiled languages such as Java (say servlets), it was not part of their core, especially for the View aspect.
However, this began to change for Java when JSP was brought to the fore. JSP provided all the required objects as implicit objects, including session and request related objects. Even though the implicit objects reduced the development time, the development of the View aspect was more or less based on reinventing the wheel.
The code implementing iteration and branching was this kind of code. This was the situation until custom tags were introduced. After their introduction, many of the daily routine codes, such as branching and looping over varied collections, made their appearance as custom tags. The standardized set of such custom tags is known as the JSP Standard Tag Library, or JSTL for short.
In this discussion I will be focusing on the basics of JSTL. The first section will focus on the terminology of the JSTL. The sets of tags within JSTL will be the focus of the second section. In the third section I will develop an application that will provide a simple interface for displaying retrieved data using the JSTL. That sets the theme for this discussion.