Module 18: Testing, Delivery, and Runtime Operations
Mini-Project: Tested, Built, and Containerized Service
Bring the engineering workflow together by taking one service from source code to tests, build, container image, and pipeline. The value of this project is not new framework syntax; it is proving that the software can be changed and delivered with confidence.
Author
Java Learner Editorial Team
Reviewer
Technical review by Java Learner
Last reviewed
2026-04-17
Java version
Java 25 LTS
Learning goals
- Package one Java service with tests, build automation, and containerization
- Create a small delivery workflow that another developer or CI system can follow
- Practice the operational mindset that separates a demo app from a shippable service
Before you start
- You are comfortable building multi-class Java applications and reading project structure
Lesson roadmap: Start with the mental model, then follow the design choices, common pitfalls, and the practical workflow you should apply in a real project.
Project goal: Start with a small service and add a realistic engineering envelope around it: tests, build automation, container packaging, and CI checks.
What to practice: Unit tests, mocked collaborators where appropriate, a reproducible build, and one deployment-ready image.
Stretch ideas: Add health endpoints, environment-based config, and a pipeline that publishes a built image.
Success check: A teammate should be able to clone the project, run the tests, build it, and package it without guesswork.
Project scope: Pick a small service you already understand, then harden it. Add focused unit tests, a clean build entry point, a container image, and a simple CI plan.
Deliverables: Source code, passing tests, build instructions, Dockerfile, sample run command, and a pipeline definition or step-by-step CI checklist.
Milestone plan: First make the build reproducible, then add or improve tests, then add the Docker image, then encode the process in CI. This keeps the workflow honest.
Professional finish: Include a README that explains setup, run commands, test commands, configuration, and where to look if the build fails.
How to study this module: Treat every tool here as part of one delivery pipeline. Tests, builds, containers, and CI are not separate checkboxes; together they decide whether other people can trust your code.
Code review mindset: Good engineering workflow reduces risk. Reviewers look for repeatable builds, focused tests, useful failure messages, and deploy steps that are automated rather than tribal knowledge.
Production habit: Make the safe path the default path. The easier it is to run tests, build images, and verify changes, the more often the team will actually do it.
Runnable examples
A project is stronger when verification is automated
./gradlew test
./gradlew bootJar
docker build -t task-api .Expected output
The service is tested, packaged, and ready for a repeatable runtime image build.
A project is stronger when one command runs the full verification path
./mvnw clean verifyExpected output
One predictable command becomes the backbone for local development and CI.
Common mistakes
Adding Docker and CI before the local build and test path are reliable
Stabilize the local verification workflow first, then automate it outward.
Calling the project production-ready without documenting how to run or verify it
Good delivery includes clear instructions and evidence that the service can be verified repeatably.
Mini exercise
Choose one existing project and list the work needed to make it “deliverable”: missing tests, missing wrapper, missing Dockerfile, missing environment docs, and missing CI steps.
Summary
- Professional readiness includes tests, builds, and packaging, not only source code.
- Automation reduces manual release friction.
- This project ties development practices to a real service workflow.
- Shipping software means more than having source code that compiles once.
- A tested, containerized, documented project is far more valuable than a feature-rich but fragile demo.
Next step
The final module turns these ideas into portfolio-ready capstones with clearer scope, milestones, and delivery expectations.
Sources used