Overview

To create a simple spring boot application, as the very famous example “Hello World!”, you don’t need to use an IDE software. Fortunately, you can use only gradle CLI, and the Gradle website explains how to do this via its simple tutorial. I will try to sumarize it in this article

Getting Started

Initialize your project via gradle

gradle init --type java-application

It will create this directory structure adding some files

$ tree spring-hello-world/
spring-hello-world/
├── build.gradle
├── gradle
│   └── wrapper
│       ├── gradle-wrapper.jar
│       └── gradle-wrapper.properties
├── gradlew
├── gradlew.bat
├── settings.gradle
└── src
    ├── main
    │   ├── java
    │   │   └── spring
    │   │       └── hello
    │   │           └── world
    │   │               └── App.java
    │   └── resources
    └── test
        ├── java
        │   └── spring
        │       └── hello
        │           └── world
        │               └── AppTest.java
        └── resources

Modify the build.gradle file adding the plugin and dependencies block

Creating a “Hello World” sample application

mkdir src/{main,test}/java/hello

Into src/main/java/hello dir add two files: App.java and HelloGradleController.java

And within the src/test/java/hello create this file:

AppTest.java

Define the main class name for the spring boot jar file. In your build.gradle file add this block

application {
   mainClassName = 'hello.App'
}

bootJar {
    mainClassName = 'hello.App'
}

At this point, you could build and run the application

./gradlew bootJar

Or using the jar file

java -jar ./build/libs/spring-hello-world.jar

Another way to run the Application is by executing the following Gradle command:

./gradlew bootRun

Sample: