So you want 100% of your deploys to be slower and less convenient than they need be just because you need to use another tool for 10% of them (and mostly for code that wasn't even written in the organization, so those images might not even need to be maintained by the organization)? I'd understand if you'd want to do that for a 50-50 mix, but not 90-10.

Also, remember that Capsule doesn't add another build step. You need to create JARs anyway, so you might as well make them capsules. You then either have the option of adding another step of building Docker images (just because you have some other Docker containers, most of them not even built by you) or not. Capsule just saves you that extra step and still lets you isolate your app in a container if you want, while making everything faster and management+logging easier. I don't think the need/wish to use containers for isolation should dictate your packaging solution.

Docker is incredibly good at caching, the assumption that Docker is slow is incorrect. The first time you build or pull an image on a machine, it might take a few to get the base images, but past that it is lightning fast, and it works the same for any language and any stack.

For most companies that operate several services, having one trusted and strong way to deploy and orchestrate is way more important than an occasional load/build time when working on a new laptop / instance.

Edit: I'm not saying Capsule isn't useful, it just doesn't make any sense to say it compares to Docker, because the use-case is quite different in reality.

What makes Docker-based deploys of JVM applications slower than Capsule-based deploys? All of an organization's Docker images for JVM applications would probably be based on the same base image, so there's no waste there.

Because you still need the extra step of creating the images (and layering them carefully if you want them to share dependencies other than the JVM). To run a capsule inside a container (if you want to run it in a container), you just tell Shield to launch the capsule JAR (which is created anyway by the build). In fact, you can even embed Shield itself in the capsule.