Level: Beginner
Time: ~60 minutes

Learning Objectives

  • Install JDK 17+ and verify the installation
  • Choose and set up a build tool (Maven or Gradle)
  • Use Spring Initializr to generate a project
  • Run the generated app from IDE and command line

2.1 Java Development Kit (JDK)

Requirement

  • Spring Boot 3.x: Java 17 minimum
  • Spring Boot 4.x: Java 17+ (supports up to Java 25)

Install JDK

Option A: Eclipse Temurin (recommended)

Option B: Oracle JDK

Option C: SDKMAN (macOS/Linux)

sdk install java 21.0.1-tem
sdk use java 21.0.1-tem

Verify

java -version
javac -version

You should see version 17 or higher.

2.2 Build Tools

Spring Boot works with Maven or Gradle. You only need one.

Maven

  • Install: maven.apache.org or use the wrapper (mvnw) included by Initializr
  • Verify: mvn -v

Gradle

  • Install: gradle.org or use the wrapper (gradlew) from Initializr
  • Verify: ./gradlew --version or gradle --version

Tip: Prefer the wrapper (mvnw/gradlew) so students use the same version without installing Maven/Gradle globally.

2.3 Spring Initializr

start.spring.io generates a ready-to-run Spring Boot project.

Steps

  1. Open https://start.spring.io
  2. Project: Maven or Gradle
  3. Language: Java (or Kotlin)
  4. Spring Boot: Latest 3.x (e.g. 3.2.x) or 4.x
  5. Metadata: - Group: com.example (or your domain) - Artifact: demo - Name / Description: optional - Package name: usually same as Group
  6. Packaging: Jar
  7. Java: 17 or 21
  8. Dependencies: Add: - Spring Web — for REST/MVC (we use this in the first app)
  9. Click Generate and download the ZIP

What You Get

  • pom.xml (Maven) or build.gradle (Gradle)
  • src/main/java — main application and packages
  • src/main/resources — application.properties, static, templates
  • src/test/java — test skeleton
  • Wrapper scripts: mvnw/mvnw.cmd or gradlew/gradlew.bat

2.4 IDE Setup

IntelliJ IDEA

  • File → New → Project from Existing Sources and select the project folder, or open the pom.xml / build.gradle
  • JDK: Project Structure → Project → SDK = 17 or 21
  • Run: open the main class (with @SpringBootApplication) and click Run

Eclipse (with Spring Tools)

  • Install Spring Tools 4 from the Eclipse Marketplace
  • File → Import → Maven/Gradle → Existing Project
  • Right-click project → Run As → Spring Boot App

VS Code

  • Install Extension Pack for Java and Spring Boot Extension Pack
  • Open folder; run from the main class or use the Spring Boot dashboard

2.5 Run the Application

From IDE

  • Open the class that has @SpringBootApplication and main(String[] args)
  • Run that class (e.g. green play button)

From Command Line

Maven:

./mvnw spring-boot:run

Gradle:

./gradlew bootRun

Build a JAR and Run

Maven:

./mvnw clean package
java -jar target/demo-0.0.1-SNAPSHOT.jar

Gradle:

./gradlew clean bootJar
java -jar build/libs/demo-0.0.1-SNAPSHOT.jar

Then open http://localhost:8080. The template project may show a Whitelabel error page until you add a controller — that’s expected.

2.6 Troubleshooting

Issue Check
java: command not found JDK not installed or not on PATH
Wrong Java version JAVA_HOME and java -version
Port 8080 in use Change server.port in application.properties or stop the other process
Maven/Gradle not found Use wrapper: ./mvnw or ./gradlew

Summary

  • Install JDK 17+ and a build tool (or use wrappers).
  • Use Spring Initializr to create a project with Spring Web.
  • Run with IDE or ./mvnw spring-boot:run / ./gradlew bootRun.
  • Build a JAR with package / bootJar and run it with java -jar.

Exercises

  1. Generate a project from start.spring.io with Spring Web and run it; confirm it starts on port 8080.
  2. Change the server port to 9090 via application.properties and run again.
  3. Build the JAR and run it from the command line without the IDE.