Java Queries

What are the differences between static and a dynamic include?

Static include <%@ include %> :
During the translation or compilation phase all the included JSP pages are compiled into a single Servlet.

Dynamic include <jsp:include …..>:
The dynamically included JSP is compiled into a separate Servlet.

What are the main elements of JSP? What are scriplets? What are expressions?

There are two types of data in a JSP page.

1. Static part (ie HTML, CSS etc), which gets copied directly to the response by the JSP Engine.
2. Dynamic part, which contains anything that can be translated and compiled by the JSP Engine.

What is a filter, and how does it work?

A filter dynamically intercepts requests and responses to transform or use the information contained in the requests or responses but typically do not themselves create responses. Filters can also be used to transform the response from the Servlet or JSP before sending it back to client.

What is the difference between forwarding a request and redirecting a request?

REDIRECT:
Sends a header back to the browser, which contains the name of he resource to be redirected to. The browser will make a fresh equest from this header information. Need to provide absolute URL path.

Explain the life cycle methods of a JSP?

• JSPs Pre-translated: Before the JSP file has been translated and compiled into the Servlet.
• JSPs Translated: The JSP file has been translated and compiled as a Servlet.
• Initialized: Prior to handling the requests in the service method the container calls the jspInit() to initialize the Servlet.

What is a JSP? What is it used for? What do you understand by the term JSP translation phase or compilation

JSP (Java ServerPages) is an extension of the Java Servlet technology. JSP is commonly used as the presentation layer for combining HTML and Java code. While Java Servlet technology is capable of generating HTML with out.println(“….. �) statements, where out is a PrintWriter.