Do you know where Java gets its simplicity in developing high-end web applications? The answer lies in Java servlets. Servlets are Java classes that extend the capabilities of servers to generate dynamic content for web applications. And, because servlets are fundamental to Java web development, interviewers often ask questions on this topic. That’s why we have prepared a list of the top 20+ interview questions on Java servlets for you.
By understanding these questions and learning how to answer them, you can feel more confident and improve your chances of succeeding.
Here we go!
Interview Questions on Java Servlets for Freshers
Here are some basic interview questions on Java servlets and their answers for freshers.
- What is a servlet?
A servlet is a Java class that runs on the server to handle client requests in web applications. It extends the functionality of servers by generating dynamic content.
Servlets facilitate the processing of HTTP requests and enable the creation of interactive web applications by responding to client actions.
- How do servlets differ from regular Java classes?
Servlets are special Java classes designed for server-side programming, whereas regular Java classes are used for general-purpose programming.
- What is the purpose of a servlet container?
A servlet container, like Apache Tomcat, is responsible for managing servlets, handling requests, and generating responses.
- What is the doGet() method in a servlet?
The doGet() method is used to handle HTTP GET requests sent by clients to the server.
- What is a Cookie?
A cookie is a small data snippet that persists across multiple client requests. It comprises a name, a single value, and optional attributes like comment, path, domain qualifiers, maximum age, and version number.
- Explain the difference between forward() and sendRedirect() methods.
The forward() method forwards the request from one servlet to another servlet or JSP page on the server, whereas the sendRedirect() method sends a temporary redirect response to the client’s browser.
- What is session tracking in servlets?
Session tracking is a mechanism used to maintain state information about a user’s interactions with a website across multiple requests, typically using HTTP session objects in servlets.
Interview Questions on Java Servlets for Experienced
A list of important interview questions on Java servlets and their answers for experienced candidates.
- What is the difference between HttpServlet and GenericServlet?
HttpServlet is a subclass of GenericServlet that provides HTTP-specific functionality, such as handling HTTP requests and responses. GenericServlet is an abstract class that serves as a base for all servlets, including HttpServlet.
- How do you handle form data in a servlet?
Form data can be retrieved in a servlet using the request.getParameter() method to access individual form parameters. Alternatively, request.getParameterMap() can be used to retrieve a map of all form parameters.
- Explain the servlet lifecycle.
The servlet lifecycle consists of several stages: initialization, service, and destruction. During initialization, the servlet is instantiated and initialized.
In the service stage, the servlet handles client requests. Finally, during destruction, the servlet is destroyed and released from memory.
- What is session management in servlets?
Session management in servlets involves maintaining state information about client sessions across multiple requests. This can be achieved using HttpSession objects, which allow servlets to store and retrieve session-specific data.
- What is the purpose of servlet filters?
Servlet filters intercept incoming requests and responses to perform pre-processing or post-processing tasks, such as authentication, logging, or modifying request parameters.
They provide a reusable mechanism for applying common functionality across multiple servlets.
- What are the annotations used in Servlet 3?
In Servlet 3.0, annotations are used for configuration instead of XML-based configuration. The main annotations used are:
· @WebServlet: Used to define a servlet class without the need for XML configuration.
· @WebFilter: Used to define a filter class without XML configuration.
· @WebListener: Used to define a listener class without XML configuration.
- What is difference between Get and Post method?
The main difference between the GET and POST methods lies in how data is transferred.
GET sends data in the URL, visible to users and suitable for retrieving data.
POST sends data in the request body, which is not visible and is suitable for sending sensitive or large data.
Advanced Java JSP Servlet Interview Questions
A list of advanced JSP servlet interview questions and their answers.
- How do you handle exceptions in servlets?
Exceptions in servlets can be handled using try-catch blocks within the service() method or by configuring error-page elements in the web.xml deployment descriptor to specify error-handling servlets or JSP pages.
Also Read - Top 25 Exception Handling Questions In Java Interview
- Explain the MVC architecture and how it is implemented in servlets and JSP.
MVC (Model-View-Controller) architecture separates an application into three components: Model (data), View (user interface), and Controller (logic).
In servlets and JSP, servlets act as controllers handling business logic, while JSP pages serve as views to display data retrieved by servlets from models.
- What are the advantages of using custom tags in JSP?
Custom tags in JSP provide a way to encapsulate reusable pieces of code or functionality, promoting code reusability and maintainability.
They allow developers to create their own tags to perform specific tasks, reducing code duplication and improving readability.
- How do you handle session management in servlets and JSP?
Session management in servlets and JSP involves using HttpSession objects to maintain state information about client sessions across multiple requests.
Session attributes can be set, retrieved, or invalidated to store and retrieve session-specific data throughout the user’s session.
- What are the differences between cookies and session tracking in servlets and JSP?
Cookies are small pieces of data stored on the client’s browser, while session tracking in servlets and JSP involves storing session data on the server.
Cookies have size limitations and can be disabled, whereas session tracking is more secure but requires server-side storage.
Interview Questions for JSP and Servlet in Java
Here are some important interview questions for JSP and servlet in Java, along with their answers.
- What is the difference between JSP and Servlet?
JSP (JavaServer Pages) is a technology used for creating dynamic web pages with HTML and Java code, while Servlet is a Java class used to extend server functionality to handle HTTP requests and generate dynamic content.
- How do you pass data from a servlet to a JSP page?
Data can be passed from a servlet to a JSP page using a request.setAttribute() method and forwarding the request to the JSP page.
- What is the difference between ServletContext and ServletConfig?
ServletContext represents the entire web application and is shared among all servlets within the application. ServletConfig, on the other hand, is specific to each servlet and provides configuration information for that servlet, such as initialization parameters defined in the deployment descriptor.
- What is the purpose of the JSP implicit objects?
JSP implicit objects are predefined objects that are available within JSP pages without any declaration.
They provide access to various elements of the JSP environment, such as request, response, session, application, out, and pageContext, simplifying JSP page development.
Also Read - Top 25+ Frontend Interview Questions and Answers
Wrapping Up
So, these are the top 15+ interview questions on Java Servlets to help you prepare. Going through these questions will boost your confidence and increase your chances of success in landing your dream job. If you’re still on the lookout for job opportunities in Java Servlets or any other IT field, consider checking out Hirist. As India’s top IT job portal, it offers the latest and most authentic tech job listings. With the Hirist app installed on your smartphone, you can conveniently browse for jobs on the go.