Is there no Oracle JDK for docker?
No. Because you cannot distribute Oracle JDK or JRE, the license in effect doesn't allow distribution. When distributed by a third party (embedded with your app) all the liability for it not working is on that party. This is why you will not find Oracle JDK/JRE on any of the public Docker registries, or in any Linux package repositories for that matter.

You can create your own image, and install Oracle JDK or JRE using the webupd8team/java package for Ubuntu/Debian.

And if you are using Alpine Linux this blog post explains which dependencies are required, and links to StackOverflow for installation instructions.

Update: Oracle has an official Docker image on the Docker Store now. https://blogs.oracle.com/developers/official-docker-image-for-oracle-java-and-the-openjdk-roadmap-for-containers

Link to Docker Store Oracle Java Image - https://store.docker.com/images/oracle-serverjre-8