Well, the keycloak.json config is just a means to configure a KeycloakDeployment from an AdapterConfig object. Specifically for the the Spring adapter, the AdapterDeploymentContextBean would have to be aware that the deployment changed. There would be a minimal amount of code needed to support that and we can modify AdapterDeploymentContextBean to be more flexible.
Just so I understand what you're asking for: you want to be able to update a KeycloakDeployment on-the-fly, correct? Also, you're aware that a keycloak.json can be configured at startup via either environment variables on command like properties, correct? You have to change at runtime?
I think the AdapterDeploymentContextBean should be as flexible as possible, however I have a small concern about the security of allowing certain properties to be swapped at runtime (e.g. the realm-public-key and the auth-server-url).
Best,
Scott