Here's what I suggest:
If you follow the demo / doc instructions - you will get the HTML reports in say target/cucumber-html-reports
, and this is "pure Maven and Java", no dependency on CircleCI at all so far.
Now all you need to do is somehow make these HTML reports accessible via the web. In Jenkins, there is an HTML Publisher Plugin. I am not familiar with CircleCI but a quick search suggests that there is a way to expose links to build artifacts.
Also note that when you follow the demo, Java JUnit XML reports would also be output to target/cucumber-reports
. It looks like CircleCI has support for these which means that it should be able to derive the build pass/fail status and stats if configured right.
Also note that Karate now enables you to write custom reports: https://stackoverflow.com/a/66773839/143475
EDIT: It seems that Circle CI plays well with Docker, so refer Karate's docs here for Docker recipes: https://github.com/karatelabs/karate-examples/blob/main/docker/README.md
And I found a thread on Circle CI discussions that may be useful to work out how to integrate Karate: https://discuss.circleci.com/t/working-with-a-machine-executor/23304
There may be some tips in the answer and comments here: Integrating Karate with Circleci (Config.yml)