Interviewing Tips

With the plenty of FAQ/Q&A available on Internet & books, most of the programmers are aware of nature of questions. If any one get selected by sheer power of raw memory, I guess that is unfair. Memory is also important but definitely not more important than the ability to assimilate just in time information to solve a particular problem.This is more important with the advent of Google Search & development methods.
So I think we should give 50-50 for both knowledge & analytical skills. We cannot undermine any of these two, both are equally important. With amount of APIs and available options we cannot afford to have good analytical person taking more than few months to learn & apply in 6-7 month duration projects.

Give a problem and see how the API design is done for that. Look out for class names, method names and handling alternate flows. Naming classes/methods and cache invalidation remains toughest part of the software creation. Probe on what difficult problem they have solved so far.

Q & A on factual details aren't useful & definitely not the best way to reject or consider.

Here some personal set of questions that I would like to consider while interviewing a person for technical lead position in my company. (Mainly in Java) All the professionals claiming developing web applications should be able to answer all these questions without any hesitation.

JSP/Servlet:
1. Difference b/w forward and re-direct & use cases for them
2. Difference b/w jsp include and include directive
I would expect senior guys to explain the actual implementation details by the container rather than just functional difference & usage scenario's.
3. Scope questions (session,request,application & page)
I expect senior guys to explain me terms like web clustering, session replication, load balancing, thread safety & it's implications on data stored in above scopes.
4. Explain the stateless nature of servlets,(It's life cycle, SingleThreadModel, web.xml entry requirements, ActionServlet implementation details if the candidate is aware of struts)
5. Filters, Listeners & their importnace.
6. Web framework(s) & their relative merits/de-merits. (Action Oriented Vs Component oriented) again from senior guys.

Core Java:
1. java.io.Serializable/Cloneable marker interfaces and their importance. Deep cloning Vs Shallow cloning.
Different ways of instantiating Objects & their overheads (new, Cloning, Serialize/De-serialize, reflection)
2. Collection API knowledge
Choosing a right collection is one of very important characterstic of good java programmer.
Practical usage of Map,Set,List from their experience. Performance related issues with them.
(Synchronized, Non synchronized)
A problem that involves string manipulation and usage of Collection APIs.A successful candidate should be able to produce code using proper APIs.
3. Exception Handling, Im-mutable nature of String
Any programmer who has coded in java should be easily able to tell about the difference/example for Checked Exception & Unchecked Exception. It will be interesting to debate on this issue with senior guys taking popular framework into consideration.

For Example reversing a given set of string with removing duplicates & sorting them alphabetically in case insensitive manner. Candidate should be able to pick up TreeSet, Comparator & String manipulation stuff.
Searching for a string in a file, It's important to see how the candidate write the code taking performance, Exception handling into consideration.

JDBC/Database:
1. Importance Normalization & join.
Difference between an inner join and an outer join
2. foreign key constraint? what can happen when you try to delete a parent record?
3. ResultSet, Template pattern, How to get column details from the table name?
4. A SQL query problem involving either outer or inner join with aggregate functions.
5. Dirty Reads/Phantom Reads. Selecting isolation levels .
6. Spring/Hibernate value addition
Spring Templates (For JDBC, Hibernate) I can't forgive a experienced person who is unaware of these APIs or he should be able to explain the home grown utility to reduce the # of lines of code in persistence layer
7. Lazy, Eager & Batch fetch strategies (With hibernate context if the candadate is hibernate aware)

Overall application architecture:
(These are must for architecture position)
1. Layering of application and their importance.
2. Technical benefits of EJB & how i tries to solve all these issues.
a. Security
b. Transactions
c. Distribution
d. Scalebility
Pragmetic aproach here should be appreciated rather than violent pro-against stand on EJB's.
3. Lightweight architectures
4. Design patterns & their benefits
You can pick up any pattern & discuss on the same, It's amzing to see people's answers when I ask difference b/w Singleton/class with all static methods & use get/set methods of javabeans :)
5. OOAD
Difference static binding Vs Dynamic binding typically discussion should start with questions like can we extend String class (with String being a final)
6. Knowledge of existing frameworks & shortcomings of those.
7. Asynchronus communication JMS, Thread, MDB

After this I have this matrix to measure the technical competence

Technology Ratings (1-5)
Core Java 3
Application/Framework 2
JDBC/DB 2

I will enter my rating (1 min & 5 Max), & it is more 5 in any he should be hired or can be considered for next round. If it is 3 in all the cases he can be considered.

In the same fashion non-technical competence can also be considered. But I don't want really want to consider this (May be as input for HR guys)

Criteria Ratings(1-5)
Previous Company/Projects 3
Academic Record/Stream 1
Attitude/Communication 2

For management position
1. Estimation techniques.
FP, WBS
2. Conflict solving ability
3. CMM levels & overall quality processes

Any thoughts on this??