The answers are very brief and are intended to provide the direction towards which one should format his answer. Be more detailed and clear with your answers. All the best.
1) How do you differentiate between Core Java and Enterprise Java?
Expected Ans: Core Java is something that provides the API's like regular expression, String handling, collections. But enterprise java involves writing scalable, secure and per-formant applications which can have large user base.
2) What do you generally do after you have resolved a problem?
Expected Ans: Perform the Root Cause Analysis and make sure the changes done have not effected any other module.
3) What is JSON? Can you represent JSON as Java Object
4) What kind of HTTP request does the <a href="url">text</a> generate?
Expected Ans: It will generate HTTP GET request
5) What are the common browser issues you will keep in mind while creating a web application?
1) User pressing back/refresh button
2) Browser crashing
3) Session issues
4) Compatibility across web browsers
6) What steps will you take for ensuring the proper security of an web application?
Expected Ans: Stuff like Encryption, Authentication and Authorization
7) The Server and Database are working fine at your end but not on customer machine. What will you do?
1) Check if the customer has not done any customizations
2) Provide a test build same as running at my end (ask customer to take a backup of their app)
3) Check out how the customer is using the application
8) A web application is running but pages are loading slow. How will you figure out what the problem is?
Expected Ans: Look for threading, database, caching issues.
9) What is the difference between frameworks like Jquery/DOJO and AJAX?
Expected Ans: Jquery and DOJO are java script frameworks for writing rich web applications but AJAX is a server communication mechanism which can issue requests without page reload.
10) What are the reasons for a page not found error and how will you sort it out?
1) The URL being sent is wrong
2) The web.xml mapping is wrong
3) The web server is down
4) The application has not been deployed
11) How will you know whether a Java file is a servlet or not?
Expected Ans: It will extend from HttpServlet class
12) When will you use Servlet and JSP or MVC framework?
Expected Ans: While framework provides a number of components and allows one to concentrate more on the business logic but Servlets and JSP are used for controller and view layer respectively.
13) What are the common issues you have faced in web applications and how did you resolve them?
1) Server not starting up. Proper heap size not set
2) Migrating from JBoss to Weblogic. Wrote a number of XML configurations
Any other generic problems faced during development/support
14) How do you keep yourself updated about the latest web technologies?
Expected Ans: Whatever websites/blogs/forums/authors you follow.
15) What was the last technical book you read?
Expected Ans: Whatever you have read