title: SwaggerUI doesn't show documented API properly generated by OpenApi codegen
body: <p>I'm using openapi-generator-maven-plugin to generate code from YAML documentation.</p>
  
  <pre><code>openapi: 3.0.3
  info:
    title: Example API Doc
    description: Those are example endpoints.
    termsOfService: https://localhost:8080/termsOfService
    license:
      name: No license
      url: https://localhost:8080/license
    version: 1.0-SNAPSHOT
  servers:
  - url: https://localhost:8080/
  - url: http://localhost:8080/
  tags:
  - name: example
    description: Example Tag
  paths:
    /example:
      get:
        tags:
        - example
        summary: Example GET request
        description: Send example GET request
        operationId: exampleGetRequest
        responses:
          200:
            description: Successful operation
            content: {}
          400:
            description: Example Bad Request
            content: {}
          404:
            description: Example Not Found
            content: {}
  </code></pre>
  
  <p>This is how I configure maven plugin to generate interfaces:</p>
  
  <pre><code>&lt;plugin&gt;
    &lt;groupId&gt;org.openapitools&lt;/groupId&gt;
    &lt;artifactId&gt;openapi-generator-maven-plugin&lt;/artifactId&gt;
    &lt;version&gt;4.1.1&lt;/version&gt;
    &lt;configuration&gt;
      &lt;generatorName&gt;spring&lt;/generatorName&gt;
      &lt;inputSpec&gt;${project.basedir}/src/main/resources/exampleApi.yaml&lt;/inputSpec&gt;
      &lt;apiPackage&gt;com.example.openapi.generated.api&lt;/apiPackage&gt;
      &lt;modelPackage&gt;com.example.openapi.generated.models&lt;/modelPackage&gt;
      &lt;generateSupportingFiles&gt;false&lt;/generateSupportingFiles&gt;
      &lt;output&gt;${project.basedir}&lt;/output&gt;
      &lt;configOptions&gt;
        &lt;dateLibrary&gt;java8&lt;/dateLibrary&gt;
        &lt;java8&gt;true&lt;/java8&gt;
        &lt;interfaceOnly&gt;true&lt;/interfaceOnly&gt;
      &lt;/configOptions&gt;
    &lt;/configuration&gt;
  &lt;/plugin&gt;
  </code></pre>
  
  <p>This plugin works well and I get interface like this</p>
  
  <pre><code>@Api(value = "example", description = "the example API")
  public interface ExampleApi {
  
      default Optional&lt;NativeWebRequest&gt; getRequest() {
          return Optional.empty();
      }
  
      @ApiOperation(value = "Example GET request", nickname = "exampleGetRequest", notes = "Send example GET request", tags = {"example",})
      @ApiResponses(value = {
              @ApiResponse(code = 200, message = "Successful operation"),
              @ApiResponse(code = 400, message = "Example Bad Request"),
              @ApiResponse(code = 404, message = "Example Not Found")})
      @RequestMapping(value = "/example", method = RequestMethod.GET)
      default ResponseEntity&lt;Void&gt; exampleGetRequest() {
          return new ResponseEntity&lt;&gt;(HttpStatus.NOT_IMPLEMENTED);
      }
  }
  </code></pre>
  
  <p>I'm implementing my interface with this class:</p>
  
  <pre><code>@RestController
  public class ExampleApiImpl implements ExampleApi {
  
      @Override
      public ResponseEntity&lt;Void&gt; exampleGetRequest() {
          return ResponseEntity.ok().build();
      }
  }
  </code></pre>
  
  <p>I've checked the solution and I've got HTTP status 200 when I perform api call, but when I try to access swagger-ui page, this API endpoint is not documented. Is there any way to configure OpenAPI UI or SwaggerUI to point to my yaml documentation?</p>
  
  <p>SwaggerUI screen
  <a href="https://i.stack.imgur.com/7jRGe.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7jRGe.png" alt="enter image description here"></a></p>