Introduction to Servlet Interview Questions and Answers
Servlet is one of the key technology for learning about advanced java or J2EE. Java Servlet is the base of any web application developing by using a J2EE platform. Currently, all the popular Java web application frameworks like Spring, Struts etc., all is actually designed based on Servlet’s basic framework.
Now, if you are looking for a job that is related to Servlet, then you need to prepare for the 2021 Servlet Interview Questions. It is true that every interview is different as per the different job profiles. Here, we have prepared the important Servlet Interview Questions and Answers, which will help you get success in your interview.
In this 2021 Servlet Interview Questions article, we shall present the 10 most important and frequently asked Servlet Interview questions. These questions are divided into two parts are as follows:
Part 1 – Servlet Interview Questions (Basic)
This first part covers basic Servlet Interview Questions and Answers
Q1. We normally get two very common servers name in the IT industry; people are calling the web server and application server. Please give some differences in details between a web server and an application server?
A web server is mainly handling end-user request and response. It was normally responsible for handling HTTP request from the client browser and responding the same with proper HTML response. One of the main utility of a web server that it understands HTML language properly and run on a specific define HTTP protocol.
The application server, in another way which has some of the key additional features like Enterprise Java Bean (EJB) support, Transaction Management ability, JMS messaging ability etc. So an application server can assume a web server with some additional features.
Q2. Every web application normally followed the common HTTP method. Explain which HTTP method can be called as non-idempotent?
This is the basic Servlet Interview Question asked in an interview. Servlet HTTP methods have followed some defined method structure. One HTTP method can be called as an important method if that method always returns the same value or the same result. Suppose some of the key methods of Servlet HTTP like getting, delete, put, head, options all are considering as the idempotent method. The funny thing is, we should need to implement that method in such a way that those methods always return the same result. Otherwise, the servlet will not work. But servlet POST method can be considered as the non-idempotent method as we should planning to proper implementation of some critical changes as per the requirement with every valid request in this POST method.
Q3. Two key methods of servlet normally define in a servlet life cycle. Key methods are Get and Post; please explain proper differences between those?
There have some several differences available in Servlet GET and POST methods; differences are:
- GET is actually one idempotent or safe method, whereas POST is not a safe method it is called non-idempotent.
- In the case of GET method, we have to limit our sending data in the request, as the GET method request should go through the request URL. Whereas POST method request can contain huge values as it moves through a request body.
- GET request is definitely not secure as the entire request can display in the URL, where POST request obviously is more secure as it is inside the request body.
- An HTTP default method is GET, but we need externally define POST for processing the request through it.
Q4. Explain details about the MIME type available in Servlet?
The MIME type is one of the response headers mentions for any Servlet page in the ‘Content-type’ attribute. It is mainly using to mention request data type to the client so that the client can clearly understand what the exact data is sending, how it can be managed and rendered to the end-user. Some of the popular MIME type in servlet are text/HTML, application/XML etc.
Let us move to the next Servlet Interview Questions
Q5. In the IT industry, one of the very common and popular applications is Web Application. Please explain what is the exact meaning of web application, how the possible directory structure needs to be maintained for executing or planning one web application properly?
Web Application is one of the popular modules in the IT industry which can be generated for presenting the static and dynamic screen to the end-user through a specific browser. Apache web server is one of the key server normally using in the current industry; it is given the environment a running web application that develops in PHP. And it also able to run the java web application, which mainly depends on servlet and JSP for running web applications in the Apache webserver environment.
Java Web application can be packaged as.WAR, EAR file can deploy in any supported server. The normal folder structure of any web application is defined in the below tree structure:
Web application Root Directory à WEB-INF, WEB CONTENT, META-INF à CLASSES, LIB, web.xml, MANIFEST.MF, JAVA SOURCE CODE, JSP or JS
Part 2 – Servlet Interview Questions (Advanced)
Let us now have a look at the advanced Servlet Interview Questions.
Q6. Explain in details your clear understanding of Servlet in Java J2EE?
JAVA Servlet is one of the key technology of Java/J2EE environment which provide one server-side technology forgiven a wonderful opportunity on displaying dynamic and static data in the client browser screen properly by using web server environment. It normally has two key packages, javax.servlet and javax.servlet.http, all the interfaces and classes define inside those packages can be utilized for designing servlet page.
Q7. Earlier servlet people were normally using CGI for preparing one web application, but after inventing of a servlet in Java/J2EE, the industry is going to use servlet directly. Please explain all the advantages of using servlet compare to CGI?
CGI technology is one of the oldest approaches for creating a web application and rendering the same to a client browser. Servlet technology mainly introduces for overcoming some of the key problems of CHI technology. Differences are below:
- Servlet always provided better performance than CGI on processing request and response in a client browser. As servlet always support multithreading, so every request will create a new thread, which obviously helps for better performance than creating a new object every time.
- Servlet is always a platform and system independent. So application developed in servlet can run in any supporting server like tomcat, web sphere, Weblogic etc., and any system platform like Windows, Linux etc.
- Servlet container has always been taken care life cycle of a servlet, so we don’t need to worry about some of the key features like leaking memory, security or garbage collecting kind of common activities.
Let us move to the next Servlet Interview Questions
Q8. Servlet has one of the common containers, which is called Servlet Container. Please explain in details about some common task done by the servlet container in the case of a servlet-based web application?
Servlet container is one of the keys contain for any servlet-based application. It sometimes called as the web container. Some of the key tasks have been performed by the servlet container; those are below:
- Support of communication between client and server.
- Managing servlet lifecycle and using resources.
- Supporting multithreading
- Supporting JSP
- Some undefined or miscellaneous task.
Q9. One of the key objects for Servlet is the servlet config object. Please explain in details about the ServletConfig object using in the servlet-based web application?
This is the most asked Servlet Interview Question in an interview. ServletConfig is normally holding configuration information of one specific servlet. Every servlet should have one servlet config object, which always initializing before starting the servlet by the container.
Q10. Provide some proper differences between servlet config and servlet context?
Servlet-Config and SevletContext both are playing a very important role in running one web application. The difference between servlet config and servlet context is as follows:
- ServletConfig has always been unique for one individual servlet, whereas ServletContext has also been unique but for an entire application.
- Both are holding init parameters, servletconfig is for one individual servlet, and servletcontext is for the entire servlet define in the application.
- ServletContext accepted to add one attribute, but servletconfig don’t.
This has been a guide to the list of Servlet Interview Questions and Answers. Here we have studied the most useful 10 interview sets of questions so that the jobseeker can crack the interview with ease. You may also look at the following articles to learn more –