1. What is JSP?
JSP stands for JavaServer Pages. It is a technology used to create dynamic web pages and is an extension of the Java Servlets API.

2. What are the advantages of using JSP?
– JSP pages can be easily maintained as they separate the dynamic content from the static content.
– The Java programming language is used to write the dynamic content, making it easy for Java developers to work with.
– JSP provides a higher level of abstraction than Servlets, allowing developers to focus more on the application logic.

3. What is a JSP container?
A JSP container is a part of a web server or application server that manages JSP pages. It compiles JSP pages into Java servlets, manages their lifecycle, and handles requests and responses.

4. How can you include a file in a JSP page?
You can include a file in a JSP page using the `` tag. For example, `` will include the content of the “included.jsp” file in the current JSP page.

5. What is the difference between and <%@ include %>?
The `` tag is a dynamic include whereas `<%@ include %>` is a static include. The dynamic include evaluates the included file at runtime, while the static include includes the file during the JSP page compilation.

6. What is JSTL?
JSTL (JavaServer Pages Standard Tag Library) is a collection of custom tags that provide common functionality to JSP pages, such as looping, conditional statements, and formatting. It simplifies JSP page development by reducing the need for Java code.

7. What are the different types of JSP directives?
There are three types of JSP directives:
– `<%@ page %>` directive is used to set page-specific attributes like language, content type, and session configuration.
– `<%@ include %>` directive is used to include a file during compilation.
– `<%@ taglib %>` directive is used to import a tag library into the JSP page.

8. What is the JSP expression language (EL)?
The JSP expression language (EL) is a scripting language that simplifies the retrieval and manipulation of data in JSP pages. It provides a way to access JavaBean properties, arrays, and other objects using simple expressions, such as `${variable}`.

9. What is the difference between request scope and session scope?
The request scope is used to store data that is specific to a particular request/response cycle, while the session scope is used to store data that is accessible across multiple requests from the same client.

10. What is the use of the JSP useBean action?
The JSP useBean action is used to instantiate and use a JavaBean in a JSP page. It allows you to create an instance of a Java class and store it as a request, session, or application attribute for use in the page.

11. What is JSP expression tag?
The JSP expression tag `<%= %>` is used to evaluate and display the result of an expression within the HTML content of a JSP page. It is usually used to display dynamic data, such as the value of a variable or an expression.

12. How can you prevent caching in JSP?
You can prevent caching in JSP by including the following directives:
“`jsp
<% response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1. response.setHeader("Pragma", "no-cache"); // HTTP 1.0. response.setDateHeader("Expires", 0); // Proxies. %>
“`

13. What are cookies in JSP?
Cookies are small pieces of data stored on the client’s computer by the web server. They can be used to store user preferences, track user behavior, and maintain session information in JSP applications.

14. How can you pass parameters from one JSP page to another?
You can pass parameters from one JSP page to another using the request object and query strings. For example, you can pass a parameter called “id” as follows:
“`
Click here
“`
In the “next.jsp” page, you can retrieve the value using:
“`
String id = request.getParameter(“id”);
“`

15. What are JSP standard actions?
JSP standard actions are predefined actions that are included in the JSP specification. They provide a way to perform common tasks, such as including files, handling exceptions, and manipulating session attributes. Examples of JSP standard actions include ``, ``, and ``.

16. What is the difference between forward and sendRedirect in JSP?
The forward action in JSP forwards the request and response objects to another resource within the server, typically another JSP page or a servlet. The URL remains the same in the browser.
The sendRedirect method redirects the client to a different URL. The URL changes in the browser.

17. What is the purpose of JSP declarations?
JSP declarations (`<%! %>`) are used to declare methods, variables, and classes that are accessible throughout the JSP page. They are typically used to define helper methods or to initialize variables.

18. What is JSP scripting element?
JSP scripting elements (`<% %>`) are used to embed Java code within a JSP page. You can use scripting elements to perform complex calculations, database operations, or other tasks that require Java code.

19. How can you handle exceptions in JSP?
You can handle exceptions in JSP using the `<% try {} catch() {} %>` block. Within the catch block, you can display an error message or perform any necessary error handling tasks.

20. What is the “isThreadSafe” attribute in a JSP page directive?
The “isThreadSafe” attribute in a JSP page directive specifies whether the JSP page is thread-safe or not. If set to true, the JSP container ensures that only one thread is accessing the page at a time, making it thread-safe.

1. What is the difference between include directive and include action in JSP?
Include directive instructs the JSP container to include the content of another resource during the translation phase, while include action includes the content of another resource during the execution phase.

2. What is the difference between and response.sendRedirect() in JSP?
forwards the request to another resource on the server without the client being aware of it, while response.sendRedirect() sends a redirect response to the client, causing the client to make a new request to the specified URL.

3. What is JSP EL? How does it differ from standard expressions?
JSP EL (Expression Language) is a scripting language used to access data from objects within a JSP page. It simplifies the readability and reduces the need for Java code in JSP. Standard expressions are evaluated during translation time, whereas JSP EL expressions are evaluated at runtime.

4. Explain the use of JSP implicit objects.
JSP implicit objects are automatically available in every JSP page without the need for explicit declaration. They include request, response, pageContext, session, application, config, out, and exception, which provide access to various objects and functionalities of the JSP environment.

5. What is the usage of JSP tag libraries?
JSP tag libraries provide reusable components and custom tags for performing specific tasks in JSP pages. They enhance code modularity, readability, and maintenance by encapsulating complex functionalities into reusable tags.

6. What are the different types of JSP directives?
JSP directives include page, include, taglib, and attribute directives. Page directive defines page-specific attributes, include directive includes the content of another resource, taglib directive defines the custom tag library used in the JSP, and attribute directive defines attributes for a JSP tag handler.

7. How can you handle exceptions in JSP?
Exceptions in JSP can be handled using the try-catch block or by defining an error page using the page directive’s “errorPage” attribute. The error page can handle exceptions globally or specific to the respective JSP page.

8. Explain the usage of JSP expression tag.
JSP expression tag (<%= %>) is used to evaluate an expression and display its result in the output. It can be used to display variables, method return values, or any valid expression from within the JSP page.

9. Can you define a JSP tag without using a tag library?
Yes, JSP tags can be defined without using a tag library. These tags are known as “scriptless tags” and are implemented using Java classes that extend the javax.servlet.jsp.tagext.SimpleTagSupport class. They provide custom functionalities directly within the JSP page.

10. What are JSP standard actions?
JSP standard actions are predefined actions provided by the JSP specification. They include actions like jsp:include, jsp:useBean, jsp:setProperty, jsp:getProperty, etc., which provide functionalities for including other resources, managing JavaBeans, setting and getting property values, etc.

11. How can you pass data between a servlet and a JSP page?
Data can be passed between a servlet and a JSP page using request attributes, request parameters, session attributes, or by including the JSP page in the servlet response.

12. What is the role of JSP tags?
JSP tags are used to insert Java code, control flow statements, or reusable components into a JSP page. They enhance the functionality and structure of JSP pages and provide a means for encapsulating complex logic into modular components.

13. What are the different scopes in JSP?
JSP provides four scopes: page scope, request scope, session scope, and application scope. Page scope is limited to the current JSP page, request scope is specific to the current HTTP request, session scope persists across multiple requests from the same client, and application scope is shared among all users of the application.

14. Explain the concept of custom tags in JSP.
Custom tags in JSP allow developers to create their own tags for specific functionalities. They encapsulate complex logic and provide a reusable component that can be easily included in JSP pages by using the custom tag library.

15. How can you prevent JSP pages from being cached by the browser?
To prevent JSP pages from being cached by the browser, you can include the following directives at the top of the JSP page:
“`html
<% response.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); response.setHeader("Pragma", "no-cache"); response.setDateHeader("Expires", 0); %>
“`

16. How can you include a JSP page within another JSP page without affecting the request?
You can use the standard action to include a JSP page within another JSP page without affecting the request. This action allows you to include the content of the specified page at the point where the action is invoked.

17. What is the difference between JSP pageContext and servletContext?
JSP pageContext provides access to various objects and methods related to the current JSP page, including request, response, session, application, and exception objects. On the other hand, servletContext provides access to global information about the web application, like initialization parameters, servlet context attributes, etc.

18. How can you handle concurrent access issues in JSP?
Concurrent access issues in JSP can be handled by using synchronization techniques on critical sections of code or by using thread-safe operations and objects. Ensuring thread safety is crucial when multiple users can simultaneously access and modify shared data.

19. Can JSP pages be used without servlets?
No, JSP pages are typically compiled into servlets before they can be executed. The JSP container translates the JSP pages into servlet code, which is then executed by the servlet container.

20. What is the purpose of JSP pre-compilation?
JSP pre-compilation is done to improve the performance and efficiency of JSP pages. By pre-compiling JSP pages, the JSP container can detect syntax errors and potential issues before runtime, reducing the overhead of on-the-fly translation and improving overall performance.