Introduction

This is a skeleton project structure which will help you start solving the problem right away.

Tools available to you.

src/main/java is where all your java source files should be written to. Already has a Main.java file that contains the driver code.
src/test/java is where all your unit test files should be written. Make sure all your test files end with Tests.java. Example: CartTests.java, OrderTests.java.
lib contains the jar files for the IDE to provide code suggestion capabilities on external dependecies. Like JUnit5.
build.xml is a build config file. You don't need to worry about this or edit this.

We have already configured everything for you to get started with running and writing unittests rightaway.
Run the command ant test in the terminal to run unittests.
ant test will detect all test files inside src/test/java and build and run the tests.
All test files needs to end with Tests.java. Example: BooksTests.java, BooksRepoTests.java.

Ant task have already been configured for you.
Run ant dist to generate the dist.jar file. This can be found inside dist/lib/ folder.

After building your solution as per How to build your solution you can now run the dist.jar against inputs.
To run, issue the command java -jar dist/lib/dist.jar '[cmd [options...]' 'cmd [options...]'...] where
- cmd is a valid problem specific command.
- options are optional cmd specific options.
Example: java -jar dist/lib/dist.jar 'ADD APPLE 2' 'ADD ORANGE 3' 'SHOW'

Note: Each full command should be wrapped in single quotes(').

You can run these following commands on the terminal.

ant clean - will clean the older builds.
ant dist - will compile your code and build the dist.jar file inside dist/lib folder.
ant test - will build and run all your unittests. The test files are expected to reside inside src/test/java.