environment JAVA_HOME missing

[soupdiver]

Is there a reason why JAVA_HOME is not set in this image?
I just used an image which is based on this one and I had to add a certificate to the default keystore. It was a bit tricky to figure out where this was located because everything I found related to $JAVA_HOME
So is there any reason not to set this environment variable?

[yosifkit]

It seems reasonable to have one. I was testing dockerization of some java software and it required a JAVA_HOME. I am open to a PR. 😉 Not being rooted in the java world, how common is it to rely on JAVA_HOME?

This is what I had for FROM java:openjdk-7-jre:

ENV JAVA_HOME /usr/lib/jvm/java-7-openjdk-amd64

[md5]

Not being rooted in the java world, how common is it to rely on JAVA_HOME?

It's a reasonably common convention in wrapper scripts. Many wrapper scripts will follow symlinks from which java to figure out JAVA_HOME if they need it, but not all of them.

The JVM internally exposes the equivalent as the java.home system property internally, but doesn't care about JAVA_HOME itself.

[yosifkit]

Sounds good to me 👍

[rakeshnambiar]

@yosifkit I am facing this issue with openjdk8 and 9. Please help.

[wglambert]

@rakeshnambiar

The PR added the ENV variable, what's the issue you're having?

$ docker run --rm -dit --name openjdk openjdk:9
$ docker exec -it openjdk bash
root@9a4e2e73468e:/# echo $JAVA_HOME
/docker-java-home

[rakeshnambiar]

Hi @wglambert thanks for your quick reply. I am using docker-compose to run a nodejs based test-script and the docker-compose file looks like below

version: "3"
services:
    jdkSetup:
        image: java:openjdk-9
        command: echo $JAVA_HOME
        ports:
          - 6060:6060
    nodeSetup:
        image: node:alpine
        volumes:
            - ./serenityjs:/usr/src/app/serenityjs
        working_dir: /usr/src/app/serenityjs
        command: npm test
        ports:
          - 7070:7070

[tianon]

command: echo $JAVA_HOME will likely be turned into CMD ["echo", "$JAVA_HOME"] by docker-compose, which will print the literal string $JAVA_HOME. You probably want something like this instead:

command:
  - sh
  - '-c'
  - 'echo $JAVA_HOME'

[rakeshnambiar]

@tianon still it's blank:
jdkSetup_1 | my jdk

version: "3"
services:
jdkSetup:
image: java:openjdk-9
command:
- sh
- '-c'
- 'echo my jdk $JAVA_HOME'
environment:
- JAVA_HOME:/usr/lib/jvm/java-8-openjdk-amd64
ports:
- 6060:6060
nodeSetup:
image: node:alpine
volumes:
- ./serenityjs:/usr/src/app/serenityjs
working_dir: /usr/src/app/serenityjs
command: npm test
ports:
- 7070:7070

[tianon]

Oh crap, I didn't notice image: java:openjdk-9 before -- swap that to image: openjdk:9.

See https://hub.docker.com/_/java/ (deprecation notice).

[rakeshnambiar]

thanks @tianon I had a doubt on the same. Anyways tried with the image: openjdk:9 However $JAVA_HOME still empty

[tianon]

Did you docker pull openjdk:9 first?

[rakeshnambiar]

yes, I have openjdk9 and openjdk8 images
java openjdk-8 d23bdf5b1b1b 17 months ago 643MB
java openjdk-9 1800de06a3eb 17 months ago 579MB

Should I remove and try again?