Update base image as JRE-8 is not maintained

[martindsouza]

From Lutz Platen

I run a ORDS container using your Dockerfile from the Github for quite a while. A few days ago I updated to ORDS 20.3 and I wondered, that the JRE 8 base container is still used. Today I invest a moment and figured out, that the openjdk:8-jre-alpine container is no longer updated and there is no other suitable jre-alpine container available. It might be a security issue to stay on JRE 8. Debian moved in Buster a while ago from openjdk 8 to openjdk 11 due to security issues - very unusual. My APEX instance is visible in the internet, so I'm a liitlebit concerned.

I tried to run ORDS using a openjdk:11-jre and got it running after a few changes. I see the following Pro&Cons:

• openjdk:11-jre is still maintained
• container creation is simple and unchanged

• the size of the image increases from 230 MB to 500MB (while the base image is only 40 MB bigger - quite surprising)

Obvious change Dockerfile: > FROM openjdk:11-jre

Two changes in scripts/docker-run.sh:

1. Use standard Shell - line 1: #!/bin/sh
2. curl already exist and apt does not exist - comment out line 4: #apk add --no-cache curl