What is JSP (Java Server Pages)?

JSP - Java server pages.

JSP is programming language(environment) to develop dynamic web pages.

• Developed by Sun Microsystems
  
• Works on both IIS (Internet Information System) and Apache (Commonly Tomcat used)
  
• .jsp files are compiled into Java Servlets by a JSP compiler on JSP Servlet engine.
• .jsp files are parsed once and used forever.
  
• <%! ... %> is used for variable and method declarations.
• scriptlet: <% ... %> tags, any valid Java code is called scriptlet.
  
• <% -- my comment -- %> or <% /* my Comment */%>
• <%= expression ... %> - we do not use (;) at this
  
• <%@ directives ... %> : directives give special information about the page to the JSP engine.
  
• JSTL - JSP Standard tag library

Advantages:

• Multiplatform
• Component reuse by using Javabeans + EJB
• advantages of Java

Execution steps of .jsp files

• send .jsp file to JSP Servlet engine
• parse .jsp file
• generate servlet source code
• compile servlet source code into class
• instantiate servlate
• send HTML (servlet output) to client

reference