Remove JDK-20 images

[cescoffier]

From @zakkak :

JDK 21 is now out and 23.0 based on JDK 20 is no longer supported (i.e. it doesn't receive any updates):

 - graalvm-version: 23.0.1.2-Final
    java-version: 20
    tags: 23.0-java20, 23.0-jdk-20, jdk-20, jdk-20.0.2
    variants:
      - sha: be992959df83beb9f5fe0ffe4606d76b2deba6cb86322b9d3614f09a8a2fbbc8
        arch: amd64
      - sha: e6ed1f76292a5f44bff076225ebbb503b940180b14d6468d8722769ff7eb9e9e
        arch: arm64

I haven't implemented it yet, as some previous releases of Quarkus are using these images.

[zakkak]

I haven't implemented it yet, as some previous releases of Quarkus are using these images.

I don't think any Quarkus version ever used the jdk-20 tag, this was just a "preview" image for people wanting to explore JDK 20 features. Any Quarkus version relying on Mandrel 23.0 (e.g. 3.2) should be using the jdk-17 tag.

[cescoffier]

The virtual thread documentation and the native-image documentation reference this image. Let's migrate them to 21 before stopping building the image.

[zakkak]

The virtual thread documentation and the native-image documentation reference this image.

I fail to find the references, could you please provide links to the relevant parts?

[cescoffier]

@zakkak https://quarkus.io/guides/virtual-threads#using-an-in-container-build. Super simple to fix.

[zakkak]

For 3.5 and up we should indeed move it to jdk-21, for older versions we should stick to jdk-20. The image is not going away, it just won't get base image updates, as it doesn't get CPU updates so I think that's OK. Perhaps it's worth adding a note in the 3.2 docs (which is an LTS) about this.

[zakkak]

It looks like 3.2 docs don't mention the jdk-20 tag, they actually don't include the Compiling Quarkus application using virtual threads into native executable section at all.

[cescoffier]

Yes, I wrote it after 3.2. I think we can safely remove the image now.