Java 21 Support

[grey-cat-1908]

Current latest supported Java version is 17. However, Java 21 was released long time ago and is being required by some applications (like Minecraft >=1.20.5 versions).
So, please add Java 21 support

[mpilone]

I contacted support about this issue and this is the reply I received:

The current consensus is that users should go with off the shelf images and not rely on our base images.

The balenalib base images “product” is kind of influx. Originally when we started them, the docker ecosystem was very new and support for arm (6/7/8) images was almost non-existent, so we had to provide balenalib to help our customers succeed.

However, now almost a decade later, the docker images for all architectures are very well supported and maintained, so the value and advantage of the balenalib set of images has drastically diminished and the burden of keeping them as fresh as those of docker official images has become quite high. This is why you will see quite a bit of our newer blog posts, etc. promoting using the official images.

So I'd recommend exploring a move to an off the shelf base image and install JDKv21 as part of the image build.