Chapter 6

1. No: by default, any REST endpoint will have OpenAPI generated for it even if none of the MP OpenAPI annotations are used.
2. Yes: you can choose to use as many or as few of the MP OpenAPI annotations as you wish, to represent the REST endpoints in your microservice.
3. The notion is that you predefine the expected contracts of your endpoints and encapsulate these in OpenAPI documents that can be bundled with your microservice.
4. No: you just need to know what the formats of the request and response are, and then you can create your own type-safe interface.
5. By using the .../mp-rest/url MP Config setting, where ... is either the interface name of the type-safe interface or the configKey passed to the RegisterRestClient annotation.
6. One way is to register a ClientHeadersFactory implementation. Another is to list the headers in the org.eclipse.microprofile.rest.client.propagateHeaders...