Stop Writing Bad Dockerfiles: Multi-Stage Builds + Security Explained

Most Dockerfiles work - but "working" isn't the same as "good," and it definitely isn't the same as "secure." In this video, I take a basic Dockerfile for a Java Spring Boot-style app and turn it into a production-ready, security-hardened, multi-stage build — step by step. You'll learn: ✅ Why a basic Dockerfile forces your CI server (Jenkins, GitHub Actions, etc.) to have Maven and Java installed ✅ Why that setup breaks reproducibility and bloats your final image ✅ How multi-stage builds separate the "build" environment from the "runtime" environment ✅ Why the ORDER of instructions in your Dockerfile directly affects build speed and caching ✅ Security optimizations: running as non-root ✅ Regular JRE images vs distroless images - what you gain, what you trade off, and when to use each ✅ A before/after comparison of image size, attack surface, CI requirements, and rebuild speed Whether you're deploying Java apps, setting up CI/CD pipelines, or just want your Docker images smaller, faster to build, and harder to break into, this one's for you. 🔧 Tools/Tech mentioned: Docker, Java, Maven Connect with me 📺 YouTube:    / @ramanujds   📸 Instagram:   / ramanuj_das_   💻 GitHub: https://github.com/ramanujds 💼 LinkedIn:   / ramanujdas   🌐 Website: https://codewithramanuj.com