Short screening interview with HR person. I presume everyone passes this part unless you are "extra horrible" here.

Then they assign you a programming problem on HackerRank with no due date, although they seem to expect something within a week or two. Mine was: Coding Exercise - Set-Associative Cache Optimization. It's a 4-hour timed exercise once you start.

I selected Java, which does not do well when all classes are in one file. Java expects different files. For example, I had trouble declaring an interface with the correct scope so it could be found. Normally, I would just create a new file and import it; no problem. I had all kinds of trouble with static classes and references that fell apart when I tried to add generics to it. All in all, if I had a real Java platform where I could create files and change things so everything is NOT IN ONE FILE, I would have gotten it to compile.

After I was done, I wished I had picked another language that does better in one file. I realize part of the exercise was to improve bad code. However, the first thing I would have done is split every high-level class at least into files. This would get rid of the tricky hierarchy in the one file.

My suggestion to someone taking the test is: First of all, if you can, use a language that is better when things are all in one file. If you plan to use Java, practice static and non-static classes and methods. Also, practice nested classes.

Due to the ugliness of the original code and its strange hierarchy, and my main complaint – Java in one file – I do not think this is a fair exercise. I got the interface and solution right away. I just wasn't able to compile because of the strange hierarchy and mess of static and non-static classes and methods.

Exercise N way set cache optimization.