Using OpenAPI and Swagger UI

package org.acme.openapi.swaggerui;

public class Fruit {

    public String name;
    public String description;

    public Fruit() {
    }

    public Fruit(String name, String description) {
        this.name = name;
        this.description = description;
    }
}

package org.acme.openapi.swaggerui;

import jakarta.ws.rs.GET;
import jakarta.ws.rs.POST;
import jakarta.ws.rs.DELETE;
import jakarta.ws.rs.Path;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.Set;

@Path("/fruits")
public class FruitResource {

    private Set<Fruit> fruits = Collections.newSetFromMap(Collections.synchronizedMap(new LinkedHashMap<>()));

    public FruitResource() {
        fruits.add(new Fruit("Apple", "Winter fruit"));
        fruits.add(new Fruit("Pineapple", "Tropical fruit"));
    }

    @GET
    public Set<Fruit> list() {
        return fruits;
    }

    @POST
    public Set<Fruit> add(Fruit fruit) {
        fruits.add(fruit);
        return fruits;
    }

    @DELETE
    public Set<Fruit> delete(Fruit fruit) {
        fruits.removeIf(existingFruit -> existingFruit.name.contentEquals(fruit.name));
        return fruits;
    }
}

package org.acme.openapi.swaggerui;

import io.quarkus.test.junit.QuarkusTest;
import org.junit.jupiter.api.Test;

import jakarta.ws.rs.core.MediaType;

import static io.restassured.RestAssured.given;
import static org.hamcrest.CoreMatchers.is;
import static org.hamcrest.Matchers.containsInAnyOrder;

@QuarkusTest
public class FruitResourceTest {

    @Test
    public void testList() {
        given()
                .when().get("/fruits")
                .then()
                .statusCode(200)
                .body("$.size()", is(2),
                        "name", containsInAnyOrder("Apple", "Pineapple"),
                        "description", containsInAnyOrder("Winter fruit", "Tropical fruit"));
    }

    @Test
    public void testAdd() {
        given()
                .body("{\"name\": \"Pear\", \"description\": \"Winter fruit\"}")
                .header("Content-Type", MediaType.APPLICATION_JSON)
                .when()
                .post("/fruits")
                .then()
                .statusCode(200)
                .body("$.size()", is(3),
                        "name", containsInAnyOrder("Apple", "Pineapple", "Pear"),
                        "description", containsInAnyOrder("Winter fruit", "Tropical fruit", "Winter fruit"));

        given()
                .body("{\"name\": \"Pear\", \"description\": \"Winter fruit\"}")
                .header("Content-Type", MediaType.APPLICATION_JSON)
                .when()
                .delete("/fruits")
                .then()
                .statusCode(200)
                .body("$.size()", is(2),
                        "name", containsInAnyOrder("Apple", "Pineapple"),
                        "description", containsInAnyOrder("Winter fruit", "Tropical fruit"));
    }
}

$ curl http://localhost:8080/q/openapi
openapi: 3.0.3
info:
  title: Generated API
  version: "1.0"
paths:
  /fruits:
    get:
      responses:
        200:
          description: OK
          content:
            application/json: {}
    post:
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/Fruit'
      responses:
        200:
          description: OK
          content:
            application/json: {}
    delete:
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/Fruit'
      responses:
        200:
          description: OK
          content:
            application/json: {}
components:
  schemas:
    Fruit:
      properties:
        description:
          type: string
        name:
          type: string

@OpenAPIDefinition(
    tags = {
            @Tag(name="widget", description="Widget operations."),
            @Tag(name="gasket", description="Operations related to gaskets")
    },
    info = @Info(
        title="Example API",
        version = "1.0.1",
        contact = @Contact(
            name = "Example API Support",
            url = "http://exampleurl.com/contact",
            email = "techsupport@example.com"),
        license = @License(
            name = "Apache 2.0",
            url = "https://www.apache.org/licenses/LICENSE-2.0.html"))
)
public class ExampleApiApplication extends Application {
}

quarkus.smallrye-openapi.info-title=Example API
%dev.quarkus.smallrye-openapi.info-title=Example API (development)
%test.quarkus.smallrye-openapi.info-title=Example API (test)
quarkus.smallrye-openapi.info-version=1.0.1
quarkus.smallrye-openapi.info-description=Just an example service
quarkus.smallrye-openapi.info-terms-of-service=Your terms here
quarkus.smallrye-openapi.info-contact-email=techsupport@example.com
quarkus.smallrye-openapi.info-contact-name=Example API Support
quarkus.smallrye-openapi.info-contact-url=http://exampleurl.com/contact
quarkus.smallrye-openapi.info-license-name=Apache 2.0
quarkus.smallrye-openapi.info-license-url=https://www.apache.org/licenses/LICENSE-2.0.html

/**
 * Filter to add custom elements
 */
@OpenApiFilter(OpenApiFilter.RunStage.BUILD) (1)
public class MyBuildTimeFilter implements OASFilter { (2)

    private IndexView view;

    public MyBuildTimeFilter(IndexView view) { (3)
        this.view = view;
    }

    @Override
    public void filterOpenAPI(OpenAPI openAPI) { (4)
        Collection<ClassInfo> knownClasses = this.view.getKnownClasses();
        Info info = OASFactory.createInfo();
        info.setDescription("Created from Annotated Buildtime filter with " + knownClasses.size() + " known indexed classes");
        openAPI.setInfo(info);
    }

}

openapi: 3.0.1
info:
  title: Static OpenAPI document of fruits resource
  description: Fruit resources Open API documentation
  version: "1.0"

servers:
  - url: http://localhost:8080/q/openapi
    description: Optional dev mode server description

paths:
  /fruits:
    get:
      responses:
        200:
          description: OK - fruits list
          content:
            application/json: {}
    post:
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/Fruit'
      responses:
        200:
          description: new fruit resource created
          content:
            application/json: {}
    delete:
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/Fruit'
      responses:
        200:
          description: OK - fruit resource deleted
          content:
            application/json: {}
components:
  schemas:
    Fruit:
      properties:
        description:
          type: string
        name:
          type: string

mp.openapi.extensions.smallrye.openapi=3.0.2

mp.openapi.extensions.smallrye.operationIdStrategy=METHOD

quarkus.swagger-ui.path=my-custom-path

./mvnw compile quarkus:dev

00:00:00,000 INFO  [io.qua.swa.run.SwaggerUiServletExtension] Swagger UI available at /q/swagger-ui