README.md

Tutorial: Create a Docker image for a Java application

A template project to create a Docker image for a Java application. The example application exposes an HTTP endpoint.

The Docker build uses a multi-stage build setup to minimize the size of the generated Docker image.

Requirements

Docker must be installed. That's it. You do not need a Java JDK or Maven.

Usage and Demo

Step 1: Create the Docker image miguno/java-docker-build:latest according to Dockerfile. This step uses Maven to build, test, and package the Java application according to pom.xml. The resulting image is 87MB in size.

# This may take a few minutes.
$ ./create_image.sh

Example output:

Building image 'miguno/java-docker-build:latest'
...
Successfully tagged miguno/java-docker-build:latest

Step 2: Start a container for the Docker image.

$ ./start_container.sh

Example output:

Starting container for image 'miguno/java-docker-build:latest', exposing port 8123/tcp
...
Endpoint is available at http://0.0.0.0:8123/status

Step 3: Open another terminal and access the example API endpoint.

$ curl http://localhost:8123/status
{"status": "idle"}

Notes

You can also build, test, and package the Java application locally (without Docker) if you have JDK 8+ and Maven installed.

$ mvn package