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Run the Application

  1. Open IntelliJ IDEA → File → Open → Select the unzipped project folder.

  2. First-time JDK setup (if prompted):

    • IntelliJ will ask you to download a JDK. Choose the same version you selected in Spring Initializr (e.g., Java 21).
    • Click Download JDK and follow the prompts.

  3. Wait for background tasks:

    • Look for progress indicators in the lower-right corner (e.g., "Downloading Gradle dependencies" or "Indexing").
    • Let these finish – they set up your project’s tools and libraries.

  4. Run the application:

    • Navigate to the main class: src/main/java/dev/pollito/UsersManagerApplication.java. Right-click the class → Run UsersManagerApplication.main().
    main

  5. Check the run terminal:

    • After a few seconds, you’ll see something similar to Started UsersManagerApplication in 2.262 seconds (process running for 2.568).
    • This means your Spring Boot app is live!

  6. Test it out:

    • Open your browser and go to http://localhost:8080/.
    • You’ll see a Whitelabel Error Page – this is normal as we haven’t done any development yet.
whitelabel

Congratulations! Your Spring Boot app is up and running – and here’s why this is a big deal:

Before Spring Boot, getting a Java app to listen on a port like 8080 required hours of manual setup:

  • Configuring XML files (like web.xml).
  • Deploying WAR files to an external server (e.g., Tomcat).
  • Writing boilerplate code just to start the server.

Today, with Spring Boot:

  • The embedded Tomcat server starts automatically.
  • Zero code needed – the main() method does everything.
  • No XML or manual server setup.

You just witnessed Spring Boot’s magic: turning what used to be a days-long chore into a 10-second task. And we haven’t even written a single line of our own code yet!