Notes | Notion

JSP vs Servlets Comparison

Key Differences

Servlets = Business Logic* + Presentation Logic
JSP = Presentation Logic* + Business Logic
JSP is outdated but still used in legacy systems
JSP is translated into servlet during execution

JSP Implicit Objects

These are variables automatically available in JSP pages during request handling stage. They are internally local variables of the jspService() method:

Object	Type	Description
`request`	HttpServletRequest	HTTP request object
`response`	HttpServletResponse	HTTP response object
`config`	ServletConfig	Servlet configuration
`session`	HttpSession	User session object
`application`	ServletContext	Application context
`page`	Object	Current page (this pointer)
`pageContext`	PageContext	Page context for attributes
`out`	JspWriter	Output writer
`exception`	Throwable	Available only in error pages

JSP Syntax Elements

1. Directives `<%@ ... %>`

@page - Controls page properties
@include - Static file inclusion
@taglib - Import custom tag libraries

2. Declarations `<%! ... %>`

Define fields and methods (outside service method)
Used for jspInit(), jspDestroy() methods
Instance variables

3. Scriptlets `<% ... %>`

Java statements for request handling