Java Expiring App

A tiny Java 17 + Maven project packaged as a Docker image. The image/app refuses to start after a configured expiry date.

• Expiry is enforced twice:
  • In entrypoint.sh before the JVM starts
  • In the Java main method at runtime
• Default expiry date is set via APP_EXPIRY_DATE (ISO YYYY-MM-DD). The default in this repo is 2025-12-31.
  • The Docker image also bakes the expiry into /app/expiry.date. That baked value is authoritative at start time.

Build

1. Build the JAR:

mvn -q -e -B -DskipTests package

2. Build the Docker image:

docker build -t expiring-app:1.0.0 .

Optionally override default expiry at build time (baked into image via build-arg and stored in /app/expiry.date):

docker build --build-arg APP_EXPIRY_DATE=2025-11-30 -t expiring-app:trial .

Note: At runtime, setting -e APP_EXPIRY_DATE=... cannot extend the baked expiry; the entrypoint prefers the baked /app/expiry.date. If the date format is invalid, the app exits with code 41. When the image is expired, it exits with 42.

If Docker Hub is rate-limiting or blocked for you, use the alternate Dockerfile that pulls from Microsoft Container Registry (MCR):

docker build -f Dockerfile.runtime -t expiring-app:1.0.0 .

This uses mcr.microsoft.com/openjdk/jdk:17-ubuntu as the base image.

Run on macOS (local)

• Default expiry baked in image:

docker run --rm expiring-app:1.0.0

• Override expiry at runtime:

docker run --rm -e APP_EXPIRY_DATE=2025-10-31 expiring-app:1.0.0

• Inspect exit code when expired (should be 42):

set +e
docker run --rm -e APP_EXPIRY_DATE=2000-01-01 expiring-app:1.0.0
echo "Exit code: $?"

Run on Windows

Using Command Prompt (cmd):

docker run --rm expiring-app:1.0.0

docker run --rm -e APP_EXPIRY_DATE=2025-10-31 expiring-app:1.0.0

Using PowerShell:

docker run --rm expiring-app:1.0.0

docker run --rm -e APP_EXPIRY_DATE=2025-10-31 expiring-app:1.0.0

If expired, container will exit with code 42 and show an error message. Runtime APP_EXPIRY_DATE can only shorten life (e.g., 2000-01-01), not extend beyond the baked date in /app/expiry.date.

How expiry works

• entrypoint.sh checks APP_EXPIRY_DATE against current UTC date and exits 42 if past.
• App.java re-checks the same date at runtime as an additional safeguard.

This is a best-effort control. If a user rebuilds the image and removes the checks, or changes system time inside the container, they could bypass it. For typical distribution use-cases, combine with private registries, short-lived tags, or license servers for stronger controls.

Project structure

.
├─ pom.xml
├─ Dockerfile
├─ entrypoint.sh
├─ src/main/java/com/example/App.java
└─ .dockerignore