How to Reduce SpringBoot Jar Size for Faster Deployment

SpringBoot applications are easy to deploy, but when the service runs on a public cloud the generated JAR can become huge, especially if many libraries such as SpringCloud are included, making updates and deployments painful.

Step 1: Build the normal JAR and extract the BOOT-INF/lib folder. Run mvn clean install in the project root, then unzip the resulting JAR and copy the BOOT-INF/lib directory to a separate location.

Step 2: Modify pom.xml to produce a JAR without the embedded libraries. The article shows a sample POM configuration (image omitted) that excludes the lib folder from the final artifact. After editing, run mvn clean install again.

The rebuilt JAR is dramatically smaller because external JARs are no longer bundled.

Step 3: Run the slimmed JAR together with the extracted libraries. Place the previously saved lib folder and the new JAR in the same directory and start the application with: java -Dloader.path=./lib -jar your‑app.jar Alternatively, you can use Maven to copy only the required JARs with the command shown in the article (image omitted).

Note: replace /path/to/ with the actual path to your lib directory.

The final directory layout looks like:

In practice, once a project's architecture is fixed, the set of JAR dependencies rarely changes; only business logic evolves. By rebuilding only the lightweight JAR when business code changes, deployment becomes much faster.