Docker Image Optimization for Spring Boot
Docker images for Spring Boot applications often start bloated—large downloads, slow CI/CD pipelines, and unnecessary attack surface. This guide shows you how to dramatically reduce image size while improving security and build speed.
JRE Base Images on Alpine Linux
The default openjdk images are often built on top of full-sized Linux distributions (like Debian or Ubuntu) and include the full Java Development Kit (JDK).
Multi-Stage Builds
In the "old days," you'd run mvn package on your laptop or a Jenkins server and then docker build to copy the resulting JAR. This is messy and inconsistent.
Layered JARs and Caching
This is where the magic happens for developer productivity. Docker works on a Layered File System. If a layer hasn't changed, Docker reuses the cached version.