I work on Capsule.<p>It&#x27;s not about philosophy but pragmatism. Most organizations are mostly Java, and even if Java doesn&#x27;t make up 90% of the components, it makes up 90% of the deployments because that&#x27;s what the core business software uses. Such organizations get to use a a rather crude tool that takes away some of the power of their technology stack. Why not use a slimmer, faster, less-hassle tool for the majority of your deploys?<p>And if we want to talk philosophy, Docker really mixes two separate issues -- portable packaging and isolation. Capsule separates them. If you want, you can launch a capsule inside a Docker container. If you want, you can directly launch it in a more convenient container simply by launching it with Shield (or outside a container by running it directly). As Shield will be open-container-compatible, there&#x27;s no reason why Docker and Shield shouldn&#x27;t play together. And remember, Capsule requires zero additional tools on top of what developers use anyway (it&#x27;s just a plain Maven Central library that you stick in your JAR with your build tool).