Java Academy · Lesson

Packaging & Running

Package a Spring Boot app into a JAR and run it in different ways.

Lesson 3 of 38 steps

Packaging & Running is a free Java Academy lesson on CoddyKit. This is lesson 3 of 3. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Java Academy learning path, and your progress syncs across the web and the CoddyKit app. The Java Academy course includes 3 lessons in total.

Intro

Packaging means building a distributable JAR file that contains your Spring Boot app.

Maven build

Run mvn clean package. It produces a fat JAR under target/.

Code: packaging demo

This demo prints the idea of packaging into a JAR.

public class Main {
  public static void main(String[] args) {
    System.out.println("Packaging Spring Boot app...");
    System.out.println("Created target/app.jar with all dependencies.");
  }
}

Run app

Run with java -jar target/app.jar. Spring Boot launches the embedded Tomcat.

Code: run output

This simulates console output of java -jar.

public class Main {
  public static void main(String[] args) {
    System.out.println("Launching app on port 8080...");
    System.out.println("App started successfully. Press Ctrl+C to exit.");
  }
}

Docker note

You can also package into a Docker image, then run docker run -p 8080:8080 app.

Packaging check

Quick check: Which command runs a packaged Spring Boot JAR?

Answer it in the interactive lesson

Recap

Recap: Built with Maven, ran with java -jar, saw console output, and noted Docker option.

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Frequently Asked Questions

Is the “Packaging & Running” lesson free?

Yes — the full text of “Packaging & Running” is free to read here on the web. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Java Academy course, upgrade to CoddyKit PRO. The Java Academy course includes 3 lessons in total.

What will I learn in “Packaging & Running”?

Package a Spring Boot app into a JAR and run it in different ways. You practise Java Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Java Academy?

No prior experience is required. Java Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 3 of 3.

How long does the “Packaging & Running” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Java Academy lesson?

Yes. Every Java Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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