java - Why HATEOAS starts creating issue for spring-boot version >= 2.2.x during startup with Swagger 2.x?

Question

I moved my project from spring-boot 2.1.9 to 2.2.0.

While starting the project, I am facing the below error messages.

Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'org.springframework.plugin.core.PluginRegistry<org.springframework.hateoas.client.LinkDiscoverer, org.springframework.http.MediaType>' available: expected single matching bean but found 17: modelBuilderPluginRegistry,modelPropertyBuilderPluginRegistry,typeNameProviderPluginRegistry,syntheticModelProviderPluginRegistry,documentationPluginRegistry,apiListingBuilderPluginRegistry,operationBuilderPluginRegistry,parameterBuilderPluginRegistry,expandedParameterBuilderPluginRegistry,resourceGroupingStrategyRegistry,operationModelsProviderPluginRegistry,defaultsProviderPluginRegistry,pathDecoratorRegistry,apiListingScannerPluginRegistry,relProviderPluginRegistry,linkDiscovererRegistry,entityLinksPluginRegistry


Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'linkDiscoverers' defined in class path resource [org/springframework/hateoas/config/HateoasConfiguration.class]: Unsatisfied dependency expressed through method 'linkDiscoverers' parameter 0; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'org.springframework.plugin.core.PluginRegistry<org.springframework.hateoas.client.LinkDiscoverer, org.springframework.http.MediaType>' available: expected single matching bean but found 17: modelBuilderPluginRegistry,modelPropertyBuilderPluginRegistry,typeNameProviderPluginRegistry,syntheticModelProviderPluginRegistry,documentationPluginRegistry,apiListingBuilderPluginRegistry,operationBuilderPluginRegistry,parameterBuilderPluginRegistry,expandedParameterBuilderPluginRegistry,resourceGroupingStrategyRegistry,operationModelsProviderPluginRegistry,defaultsProviderPluginRegistry,pathDecoratorRegistry,apiListingScannerPluginRegistry,relProviderPluginRegistry,linkDiscovererRegistry,entityLinksPluginRegistry


***************************
APPLICATION FAILED TO START
***************************

Description:


Parameter 0 of method linkDiscoverers in org.springframework.hateoas.config.HateoasConfiguration 
required a single bean, but 17 were found:
- modelBuilderPluginRegistry: defined in null
- modelPropertyBuilderPluginRegistry: defined in null
- typeNameProviderPluginRegistry: defined in null
- syntheticModelProviderPluginRegistry: defined in null
- documentationPluginRegistry: defined in null
- apiListingBuilderPluginRegistry: defined in null
- operationBuilderPluginRegistry: defined in null
- parameterBuilderPluginRegistry: defined in null
- expandedParameterBuilderPluginRegistry: defined in null
- resourceGroupingStrategyRegistry: defined in null
- operationModelsProviderPluginRegistry: defined in null
- defaultsProviderPluginRegistry: defined in null
- pathDecoratorRegistry: defined in null
- apiListingScannerPluginRegistry: defined in null
- relProviderPluginRegistry: defined by method 'relProviderPluginRegistry' in class path resource [org/springframework/hateoas/config/HateoasConfiguration.class]
- linkDiscovererRegistry: defined in null
- entityLinksPluginRegistry: defined by method 'entityLinksPluginRegistry' in class path resource [org/springframework/hateoas/config/WebMvcEntityLinksConfiguration.class]

What could have caused this issue ?

Note: I am not using HATEOAS in my pom.xml file.

pom.xml

<properties>
    <java.version>1.8</java.version>
    <swagger-springfox.version>2.9.2</swagger-springfox.version>
    <sonar.jacoco.execPath>${project.basedir}/target/jacoco.exec</sonar.jacoco.execPath>
    <jasypt-spring-boot-starter>2.1.1</jasypt-spring-boot-starter>
    <logbook-spring-boot-starter>1.13.0</logbook-spring-boot-starter>
    <assertj-swagger>0.8.1</assertj-swagger>
    <jacoco-version>0.8.4</jacoco-version>
</properties>
<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-rest</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-configuration-processor</artifactId>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger2</artifactId>
        <version>${swagger-springfox.version}</version>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger-ui</artifactId>
        <version>${swagger-springfox.version}</version>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-spring-web</artifactId>
        <version>${swagger-springfox.version}</version>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-core</artifactId>
        <version>${swagger-springfox.version}</version>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-data-rest</artifactId>
        <version>${swagger-springfox.version}</version>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-bean-validators</artifactId>
        <version>${swagger-springfox.version}</version>
    </dependency>

Answer 1

I had this issue with Swagger + HATEOAS in my spring-boot application.

The fix is given below (edit your Swagger configuration class):

@Configuration
@EnableSwagger2
public class SwaggerConfiguration {

    @Bean
    public LinkDiscoverers discoverers() {
        List<LinkDiscoverer> plugins = new ArrayList<>();
        plugins.add(new CollectionJsonLinkDiscoverer());
        return new LinkDiscoverers(SimplePluginRegistry.create(plugins));

    }
}