[arch-general] How to have multiple JDKs parallel?

[Olli]

On 15.09.18 10:56, Peter Nabbefeld wrote:
> up to JDK 9 I didn't have problems upgrading, but since JDK 10 it always
> wants to replace JDK 9, and I guess it will become worse with JDK 11 etc.

starting with Java 9, the OpenJDK changed its release cycle to publish a
new version every six month. Each new version is replacing the previous
one so that there is always only one (the latest) supported version.
Check out e. g. this article for more details:
https://medium.com/codefx-weekly/no-free-java-lts-version-b850192745fb

Since Arch Linux closely follows upstream I think the OpenJDK packages
will follow this policy—and that this is the reason why the package
“jdk10-openjdk” replaced “jdk9-openjdk” entirely. In ten days,
“jdk11-openjdk” will replace “jdk10-openjdk” and so on …

> As a Java developer, I need to be able to have multiple JDKs for
> compatibility checkings.

Since there will be no official OpenJDK builds (no maintenance) for the
older versions anymore, you have to install them manually—or use
Oracle’s builds with longtime support (not for free though). I guess it
would be best to closely follow the latest version and always make sure
your applications are running fine. I heard that new versions should be
backwards compatible (to a certain degree) but cannot find any source
for this.

Regards,
Olli