Interview Questions

As part of my job, I am regularly interviewing developers. Often, before a interview a canidate, I do a Google search for them. What I'm hoping to find is:

Open source projects they've contributed to
Technical postings they've written on messages boards
Interesting blog postings

I well prepared canidate as likely Googled me before the interview. In fact, you the reader of this page, may be one such canidate. Well to give you a little help, I'll give you some of the questions I'll probably be asking you. I've posted a subset fo the questions which I usually ask. See also my Phone interview tips

Java Questions

What's the difference between .equals and ==. If you can't answer this, it's probably going to be a short interview.
Can you put constants in an interface? If so, is this a good idea?
Why do people say Java isn't a true object oriented language?
What is a weak reference?
In Java 1.4, how would you create a type safe enum?

C++

Explain the difference between a macro and a template.
What is an initializer list? Why use them? When would you be required to use one?
What's the difference between an int and a long?
How would you determine the number of elements in a C array?
What's the difference between a reference and a pointer? Which one do you prefer to use?

SQL

What is an inner / outer / self / theta join?
Give me an example of a query with a HAVING clause.
If you have a time series table which contains the columns instrument, date, & price, what indexes would you create?
What is meant by the ACID model?
What is a composite primary key?
How do you represent a many-to-many relationship?

Network

How can you have one thread wait on multiple sockets?
Explain how multicast works.
What are the five elements which uniquely identify a socket?
What is the purpose of the TIME_WAIT state?
If a have an echo server on a local network, how many requests per second could a single client make, assuming it has to wait for the response before sending the next request.

Architecture

What is virtual memory?
What is the difference between virtual memory and virtual address space?
What is the difference between kernel and user address space? How much of each do you get on Windows, Solaris, Linux, etc..?
What is a memory mapped file? When might you use one?

Unix

How do you check the return code of the last command which executed?
How can you tell the number of lines in a file?
If I chmod a file 644, what permissions will it have?