OpenAPI 3.0 specification was released in late 2017, and it resolved several major issues or limitations of Swagger 2.0 specification. The community is cheered about the release; however, it is very hard for developers to adopt it at the moment, even after several months since the release. Given the new specification is not backward compatible, all tools around Swagger 2.0 need to be rewritten, and it takes a lot of time.
In our example, we have added OpenAPI 3.0 support in light-rest-4j framework in late 2017 and we have to build our own openapi-parser to do the runtime validation again the spec.
Over the last couple of weeks, a lot of customers asked questions on how to migrate from the existing Swagger 2.0 API to OpenAPI 3.0 API. Also, our team has to upgrade existing tutorials and examples to OpenAPI 3.0 in light-example-4j/rest/openapi/
This document is the first step in the process that converts the existing Swagger 2.0 specification to OpenAPI 3.0 specification.