How to use this java-challenge project

Prerequisites

• Java1.8
• Maven 3.*
• Docker 20.10.6
• Docker-compose 1.29.1

How to Run this project

$ git clone https://github.com/lechatthecat/java-challenge
$ cd ./java-challenge
$ docker-compose up -d --build
$ docker ps -a
$ mvn clean package
$ mvn spring-boot:run

Now the project should be running locally. Application (with MariaDB container) is ready to be used.

You can access the url below for testing it :

• Swagger UI : http://localhost:8080/swagger-ui/#/

To connect to the MariaDB contaier, please use the following information:

• host: localhost
• port: 3306
• user id: root
• password: root
• database name: testdb

Enhancements I did

• Replaced H2 mem DB with MariaDB running on Docker container.
  • H2 DB is not supposed to be used as a main DB in production, but MariaDB and Docker can be used as a main DB in both development and production.
  • I used Docker not to reduce the project portability. H2 DB can be easily moved to other environment, but MariaDB with Docker also can be easily moved.
  • If this system were used in production, when traffic grows, MariaDB/Docker would provide better performance.
• Changed Swagger/Swagger-UI version to 3.0.0.
  • My IDE shows vulnerability warning on ver 2.9.xx, but ver 2.10.2 is broken version according to GitHub issue, so I changed it to ver 3.0.0.
  • Replaced some other dependencies' versions that can have vulnerability.
• Added validation for user input. When you pass wrong value to the endpoints, they will return validation messages.
  • Validation is performed for both of pathVariables and Employee json passed for all endpoints.
• Removed bugs.
  • "basic error controller" was removed from swagger-ui.
  • getEmployee(Long employeeId) method of EmoloyeeService returns Optional<Employee>, but controller was checking whether value/null was returned from getEmployee(Long employeeId), which is meaningless because this method always returns Optional<Employee> even if the method doesn't find any row by the specified employeeId.
• Added Transaction for UPDATE/DELETE/CREATE.
• Added 7 Unit tests.
• Added comments.
• Added simple caching logic for database calls

Enhancements I would do if I have more time

• In DB definition, "salary" column of "EMPLOYEE" table is defined as VarChar(255), which is strange. I think Int or BigInt would be better. If I had more time, I would change the column definition.
• If I had more time, I would have added more detailed caching logic (evicts only updated caches).
• I would add more unit tests and increase the coverage of unit tests.

Instructions

• download the zip file of this project

• create a repository in your own github named 'java-challenge'

• clone your repository in a folder on your machine

• extract the zip file in this folder

• commit and push

• Enhance the code in any ways you can see, you are free! Some possibilities:

  • Add tests
  • Change syntax
  • Protect controller end points
  • Add caching logic for database calls
  • Improve doc and comments
  • Fix any bug you might find

• Edit readme.md and add any comments. It can be about what you did, what you would have done if you had more time, etc.

• Send us the link of your repository.

Restrictions

• use java 8

What we will look for

• Readability of your code
• Documentation
• Comments in your code
• Appropriate usage of spring boot
• Appropriate usage of packages
• Is the application running as expected
• No performance issues

Your experience in Java

Please let us know more about your Java experience in a few sentences. For example:

• I have 3 years experience in Java and I started to use Spring Boot from last year
• I'm a beginner and just recently learned Spring Boot
• I know Spring Boot very well and have been using it for many years

My Experience in Java

• I have 3 years experience in Java and I started to use Spring Boot 2 years ago.