1.What is JSP?
JavaServer Pages (JSP) is a technology for developing web pages that support dynamic content which helps developers insert java code in HTML pages by making use of special JSP tags, most of which start with <% and end with %>.
2.What are advantages of using JSP?
JSP offer several advantages as listed below:
Performance is significantly better because JSP allows embedding Dynamic Elements in HTML Pages itself.
JSP are always compiled before it’s processed by the server unlike CGI/Perl which requires the server to load an interpreter and the target script each time the page is requested.
JavaServer Pages are built on top of the Java Servlets API, so like Servlets, JSP also has access to all the powerful Enterprise Java APIs, including JDBC, JNDI, EJB, JAXP etc.
JSP pages can be used in combination with servlets that handle the business logic, the model supported by Java servlet template engines.
3.What are the advantages of JSP over Active Server Pages (ASP)?
The advantages of JSP are twofold.
First, the dynamic part is written in Java, not Visual Basic or other MS specific language, so it is more powerful and easier to use.
Second, it is portable to other operating systems and non-Microsoft Web servers.
4.What are the advantages of JSP over Pure Servlets?
It is more convenient to write (and to modify!) regular HTML than to have plenty of println statements that generate the HTML. Other advantages are:
Embedding of Java code in HTML pages.
Platform independence.
Creation of database-driven Web applications.
Server-side programming capabilities.
5.What are the advantages of JSP over Server-Side Includes (SSI)?
SSI is really only intended for simple inclusions, not for “real” programs that use form data, make database connections, and the like.
6.What are the advantages of JSP over JavaScript?
JavaScript can generate HTML dynamically on the client but can hardly interact with the web server to perform complex tasks like database access and image processing etc.
7.What are the advantages of JSP over Static HTML?
Regular HTML, of course, cannot contain dynamic information.
8.Explain lifecycle of a JSP.
A JSP Lifecycle consists of following steps:
Compilation: When a browser asks for a JSP, the JSP engine first checks to see whether it needs to compile the page. If the page has never been compiled, or if the JSP has been modified since it was last compiled, the JSP engine compiles the page.
The compilation process involves three steps:
Parsing the JSP.
Turning the JSP into a servlet.
Compiling the servlet.
Initialization: When a container loads a JSP it invokes the jspInit() method before servicing any requests
Execution: Whenever a browser requests a JSP and the page has been loaded and initialized, the JSP engine invokes the _jspService() method in the JSP.The _jspService() method of a JSP is invoked once per a request and is responsible for generating the response for that request and this method is also responsible for generating responses to all seven of the HTTP methods ie. GET, POST, DELETE etc.
Cleanup: The destruction phase of the JSP life cycle represents when a JSP is being removed from use by a container.The jspDestroy() method is the JSP equivalent of the destroy method for servlets.
9.What is a sciptlet in JSP and what is its syntax?
A scriptlet can contain any number of JAVA language statements, variable or method declarations, or expressions that are valid in the page scripting language.
Following is the syntax of Scriptlet:
<% code fragment %>
10.What are JSP declarations?
A declaration declares one or more variables or methods that you can use in Java code later in the JSP file. You must declare the variable or method before you use it in the JSP file.
<%! declaration; [ declaration; ]+ … %>
