Norman Maurer 0d37b06bc8 Update JDK12 and 13 to latest EA releases. (#8809)
Motivation:

We use outdated EA releases when building and testing with JDK 12 and 13.

Modifications:

- Update versions.
- Add workaround for possible JDK12+ bug.

Result:

Use latest releases
2019-02-28 13:55:01 +01:00
..

Using the docker images

cd /path/to/netty/

centos 6 with java 8

docker-compose -f docker/docker-compose.yaml -f docker/docker-compose.centos-6.18.yaml run test

centos 7 with java 9

docker-compose -f docker/docker-compose.yaml -f docker/docker-compose.centos-7.19.yaml run test

etc, etc