JSP Interview Questions

• What is the JSP pageContext object?

The JSP pageContext object provides access to various objects and information related to the JSP page, such as request, response, session, and application objects.

• What is the difference between include and forward in JSP?

Include and forward are used for including the content of another resource in the current page. The main difference is that include includes the content of the other resource and continues processing the current page, while forward forwards the request to the other resource and stops processing the current page.

• What is the difference between GET and POST method in JSP?

GET and POST are HTTP methods used to send data from the client to the server. GET is used for retrieving data from the server, while POST is used for submitting data to the server for processing.

• What is the purpose of JSP expression language?

The purpose of JSP expression language is to simplify the process of accessing and manipulating data stored in objects in JSP pages. It provides a simplified syntax for accessing properties and methods of objects.

• What is the difference between JSP custom tags and JSP standard tags?

JSP custom tags are user-defined tags that are created for specific purposes, while JSP standard tags are built-in tags that are included in the JSP specification and are used for common tasks.

• What is the difference between JSP and PHP?

JSP is a server-side technology that uses Java, while PHP is a server-side scripting language. JSP provides a rich set of tools and libraries for developing complex web applications, while PHP is mainly used for developing simple web applications.

• What is a JSP session listener?

A JSP session listener is a Java class that implements the HttpSessionListener interface. It is used to monitor session creation and destruction events in a web application.

• What is the purpose of JSP directive page import?

The JSP directive page import is used to import Java classes and interfaces into a JSP page. This allows the JSP page to access and use the imported classes.

• What is a JSP error page?

A JSP error page is a page that is displayed when an unhandled exception occurs in a JSP page. It is used to handle errors and provide a meaningful response to the user.

• What is the difference between JSP include and JSP forward?

JSP include includes the content of another JSP page or servlet in the current page, while JSP forward forwards the request to another JSP page or servlet.

• What is the use of JSP tag libraries?

JSP tag libraries provide a set of custom tags that can be used in JSP pages to simplify the development process. They encapsulate complex behavior and make it easier to develop JSP pages.

• What is a JSP application server?

A JSP application server is a software application that provides the environment necessary for running JSP pages and Java servlets. It handles requests, manages connections, and provides services to the JSP pages and servlets.

• What is the difference between JSP and servlets?

JSP and servlets are both Java technologies used for creating dynamic web pages. The main difference is that JSP pages are primarily used for presentation logic, while servlets are used for application logic.

• What is a JSP session?

A JSP session is a way to maintain state information between multiple requests from the same client. It is implemented using cookies or URL rewriting to store session data.

• What is a JSP tag file?

A JSP tag file is a reusable JSP component that can be included in other JSP pages or tag files. It is similar to a custom tag, but is defined in a separate file.

• What is the difference between JSP scriptlets and expressions?

JSP scriptlets are used to include Java code in a JSP page, while JSP expressions are used to include the value of a Java expression in the output of the JSP page.

• What is the difference between the JSP include directive and the JSP include action?

The JSP include directive is processed at translation time, while the JSP include action is processed at request time. The include directive includes the contents of the included page in the main page, while the include action executes the included page and includes its output in the main page.

• What is a JSP custom tag?

A JSP custom tag is a user-defined tag that can be used in a JSP page to perform a specific function. It is defined using a tag library descriptor (TLD) and a Java class.

• What is the JSP EL implicit object?

The JSP EL implicit object is an object that is automatically available in JSP pages for use in expressions. It includes objects such as pageContext, request, response, session, and application.

• What is the use of the JSP useBean action?

The JSP useBean action is used to create or obtain a Java bean object and store it in a variable that can be used in the JSP page.

• What is the JSP tag library descriptor (TLD)?

The JSP tag library descriptor is an XML file that defines the custom tags that can be used in a JSP page.

• What is the JSP include directive?

The JSP include directive is used to include the contents of another file in the current JSP page. It is processed during the translation phase of the JSP page.

• What is a JSP action?

A JSP action is a special tag that performs a specific function, such as including a file, instantiating a Java bean, or forwarding the request to another page.

• What is the use of the JSP forward action?

The JSP forward action is used to forward the request to another JSP page or servlet. The forwarding is done on the server side, so the client is not aware of the change.

• What is the use of the JSP page directive?

The JSP page directive is used to define various attributes of the JSP page, such as the language used, the MIME type, and the buffer size.

• What is a JSP declaration?

A JSP declaration is used to declare variables and methods in a JSP page. It is similar to a Java class declaration.

• What is a JSP element?

A JSP element is a tag or directive used in a JSP page. It is enclosed in "<" and ">" characters.

• What is the use of the JSP param action?

The JSP param action is used to pass parameters to a JSP page or servlet. It is similar to passing parameters in a query string.

• What is the use of the JSP include action?

The JSP include action is used to include the output of another JSP page or servlet in the current JSP page. The included page is processed at request time, and its output is included in the output of the current page.

• What is the difference between the request and session objects in JSP?

The request object is used to store information that is valid only for the current request, while the session object is used to store information that is valid across multiple requests from the same client.

• What is the use of the JSP expression language (EL)?

The JSP expression language (EL) is used to evaluate expressions and output their values in a JSP page. It is a simplified way of accessing Java objects and their properties.

• What is the difference between the page directive and the include directive in JSP?

The page directive is used to specify various attributes of the JSP page, such as the language used and the buffer size, while the include directive is used to include the contents of another file in the current JSP page.

• What is the use of the JSP tag library?

The JSP tag library is a collection of custom tags that can be used in JSP pages. It provides a way to encapsulate complex functionality and reuse it in multiple pages.

• What is the use of the JSP error page directive?

The JSP error page directive is used to specify the page that should be displayed when an uncaught exception occurs in the JSP page.

• What is a JSP lifecycle?

The JSP lifecycle is the sequence of events that occur when a JSP page is requested by a client. It includes translation, compilation, initialization, service, and destruction.

• What is the use of the JSP context object?

The JSP context object is used to store information that is valid across multiple requests from all clients. It is similar to the application object in servlets.

• What is the difference between the JSP include directive and the JSP include action?

The JSP include directive is processed at translation time, while the JSP include action is processed at request time. The include directive includes the contents of the included page in the main page, while the include action executes the included page and includes its output in the main page.

• What is the use of the JSP standard tag library (JSTL)?

The JSP standard tag library (JSTL) is a collection of custom tags that provide a standard way of accessing and processing data in JSP pages. It includes tags for iteration, conditional processing, and formatting.

• What is the use of the JSP tag handler?

The JSP tag handler is a Java class that implements the functionality of a custom tag. It is responsible for processing the tag and generating its output.

• What is the use of the JSP declaration tag?

The JSP declaration tag is used to declare variables and methods in a JSP page. It is similar to a Java class declaration.

• What is the use of the JSP session object?

The JSP session object is used to store information that is valid across multiple requests from the same client. It is implemented using cookies or URL rewriting to maintain session state.

• What is the difference between a JSP scriptlet and a JSP expression?

A JSP scriptlet is used to include Java code in a JSP page, while a JSP expression is used to output the value of a Java expression in the output of the JSP page.