Docker Java Example Part 1: Initializing a new Spring Boot Project

Docker Java Example Series

1. Initializing a new Spring Boot Project
2. Spring Web MVC Testing
3. Transmode Gradle Plugin
4. Bmuschko and Nebula Gradle Plugins
5. Kubernetes

I've been wanting to learn more about Docker for a while.  I'm almost done with this udemy course Docker for Java Developers.  Its a good course, and the concepts are straightforward.  To help me commit it to memory, I wanted to do my own project to apply what I'm learning.
https://github.com/ryanmckaytx/java-docker-example
In this part, I'm just going to initialize a new project.  Part 2 covers Spring Web MVC testing.

Set up your dev machine

Every once in a while, like when you switch jobs and get a new laptop, you need to set up a machine for java development.  

For this, I like to use sdkman.  It helps install the tools you need to do java development.  It also helps switch between multiple versions of those tools.  I've installed java, groovy, gradle, and maven.

$ sdk c

Using:

gradle: 4.0
groovy: 2.4.11
java: 8u131-zulu
maven: 3.5.0

Create a new project

There are a few good ways to do this.  The typical way I do this is to copy another project.  Within an organization, or at least within a team, there is typically some amount of infrastructure and institutional knowledge built into existing projects that you want in a new project.  But for this project, I wanted to practice starting completely from scratch.  There are a couple of good options.

Gradle init

I like gradle as a build tool, and gradle has a built in project initializer.  It supports a few project archtypes, including pom (converting a maven project to gradle), java library, and java application.  It even explicitly supports spock testing framework.

$ gradle init --type java-application --test-framework spock

BUILD SUCCESSFUL in 0s
2 actionable tasks: 2 executed
$ tree
.
|____build.gradle
|____gradle
| |____wrapper
| | |____gradle-wrapper.jar
| | |____gradle-wrapper.properties
|____gradlew
|____gradlew.bat
|____settings.gradle
|____src
| |____main
| | |____java
| | | |____App.java
| |____test
| | |____groovy
| | | |____AppTest.groovy

You can see it also generates a demo App and AppTest.

Spring Boot Initializr

For Spring Boot apps, Spring provides the Spring Boot Initializr.  This lets you choose from a curated  (but extensive) set of options and dependencies, and then generates a project in a zip file for download.  Similarly to gradle init, it includes a default basic app and test.

$ unzip demo.zip
Archive:  demo.zip
   creating: demo/
  inflating: demo/gradlew
   creating: demo/gradle/
   creating: demo/gradle/wrapper/
   creating: demo/src/
   creating: demo/src/main/
   creating: demo/src/main/java/
   creating: demo/src/main/java/net/
   creating: demo/src/main/java/net/ryanmckay/
   creating: demo/src/main/java/net/ryanmckay/demo/
   creating: demo/src/main/resources/
   creating: demo/src/main/resources/static/
   creating: demo/src/main/resources/templates/
   creating: demo/src/test/
   creating: demo/src/test/java/
   creating: demo/src/test/java/net/
   creating: demo/src/test/java/net/ryanmckay/
   creating: demo/src/test/java/net/ryanmckay/demo/
  inflating: demo/.gitignore
  inflating: demo/build.gradle
  inflating: demo/gradle/wrapper/gradle-wrapper.jar
  inflating: demo/gradle/wrapper/gradle-wrapper.properties
  inflating: demo/gradlew.bat
  inflating: demo/src/main/java/net/ryanmckay/demo/DemoApplication.java
  inflating: demo/src/main/resources/application.properties
  inflating: demo/src/test/java/net/ryanmckay/demo/DemoApplicationTests.java

Pretty much the only thing I don't like here is that the test isn't spock and there doesn't seem to be a way to choose it. Not a big deal, its easy to change afterward.  I went with initializr for this project.

JHipster

JHipster is an opinionated full-stack project generator for Spring Boot + Angular apps.  It has a lot of features that I want to explore later, so for now I stuck with Spring Boot Initializr.

Add a Rest Controller

I could have gone straight to CI at this point, but I wanted to do a little extra work that I wish the Initializr could have done for me.  I copied in a basic hello world spring rest controller (and its tests) from the Spring Restful Web Service Guide.  The repo is now at this point https://github.com/ryanmckaytx/java-docker-example/tree/v0.1