The purpose of this exercise is not to give a "gotcha" question or puzzle, but a straightforward (albeit contrived) example of the kind of requirement that might arise in a real project so that we have a shared context for a technical conversation during the interview. We are interested in how you approach a project, so you should feel free to add new class files as well modify the files that are provided as you see fit. Use of your favourite libraries or frameworks is fine, but not required. How you demonstrate the correctness of your implementation is up to you.

We have a small application that provides population statistics for countries. Recently some of our customers have reported some issues with the application and we would like you to investigate the problems.

We have had several reports that in the afternoon it takes a really long time to load data. This seems to be affecting everyone and it seems to affect all of the APIs.

It looks like the service that provides country information for us has made an update, because recently we noticed that we have duplicate country names in the /all results.

One of our customers reported to us that sometimes the data they get back from our api seems incomplete: they noticed that sometimes countries are missing from the /all response.

You may import and run the project within the IDE of your choice, or run the following Gradle command to generate a jar to execute.

From the root dir execute gradlew build (./gradlew build in some environments) and then, java -jar build/libs/integration-interview.jar.

• Why not Maven?

  Primarily due to the convenience of the Gradle wrapper; you don't need to install anything and you will always be using the version specified in the project.

• When I try to run the application I get a NPE from DBManager.

  The database is a file-based SQLite database (you can find it in DBManagerImpl) - check the path is valid for your application context, or, if you're running from within an IDE, make sure the working directory is the root of the project.

• I can't get my Database tool to work.

  Try DB Browser for SQLite. Platform-specific installers and a portable version are available.

• This JSON's terrible, I can't read it.

  Well that's all part of the fun. JSON is pretty easy to format with plugins in most editors, otherwise you could use this great online formatting tool.