Practical Questions To be asked in Interviews

Listed questions are for Interviewer. Its more of a discussion to analyze how a candidate approaches to resolve these practical problems, it also will give an idea of how much grasp technically the candidate has on web technologies - java, j2ee , application servers, databases ..

These questions dont have any particular answer. These are practical problems which I have faced in web projects executed by my team.

1. How would one analyze and find solutions to HIGH CPU usage by a web application?  The CPU usage shoots close to 100% within 3 days of application server restart, and once the CPU reaches close to 100%, the web application hangs? What could be the probable causes? What would be line of approach to resolve this issue.?

Basically the candidate who answers this question, should try to reason out the issues which can shoot the CPU usage to 100%.

The Interviewer should bascially look the approach and discuss to find a solution.

I have asked this question very frequently and the answers give a very good feedback on the technology grasp of the candidate unlike theorotical questions which have one line answers.

2. How should a  web application authenticate user id / passwords combinations?

a) should the password be sent in clear text to the server for authentication ?
b) should the password be hashed ?
c) if hashed, how wud one authenicate the password at server?
d) or any other mechanism?

3. Any approach to migrate passwords from an existing web application to migrated web application. ?