Error: Invalid or corrupt jarfile /app.jar
Replace in Dockerfile
COPY ${JAR_FILE} app.jar
with
COPY ${JAR_FILE} /app.jar
Rather embarrassingly i hadn't realised that i needed to point towards the right jar file with ${JAR_FILE}
. After ensuring it was directed at my app jar it all worked. Thankyou!
Keeping here incase someone needs it.