How to set Java heap size (Xms/Xmx) inside Docker container?

Question

As of raising this question, Docker looks to be new enough to not have answers to this question on the net. The only place I found is this article in which the author is say

Answer 1

I agree that it depends on what container you're using. If you are using the official Tomcat image, it looks like it's simple enough, you will need to pass the JAVA_OPTS environment variable with your heap settings:

docker run --rm -e JAVA_OPTS='-Xmx1g' tomcat

See How to set JVM parameters?