I have a Spring configuration class like this where I need to configure 2 different Queue:

@Configuration
public class DataQueue {

    /**
     * Queue to store the {@link SlowVars} read from the PLC
     * @return the queue
     */
    @Bean
    Set<JsonNode> slowVarsQueue() {
        return new CopyOnWriteArraySet<>();
    }

    /**
     * Queue to store the {@link JsonNode} events
     * @return the queue
     */
    @Bean
    Set<JsonNode> eventsQueue() {
        return new CopyOnWriteArraySet<>();
    }
}

In the class where I need to use one queue I wrote:

@Log4j2
@RestController
@AllArgsConstructor
public class EventsApiImpl implements EventsApi {

    private Set<JsonNode> eventsQueue;
    private MariaEventService mariaEventService;
    private EventManipulationService eventManipulationService;
    private ObjectMapper mapper;

// lots of methods

}

unfortunately Springs raise an error starting:

Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean
with name 'slowVarsApiImpl': Unsatisfied dependency expressed through constructor parameter 0:
No qualifying bean of type 'java.util.Set[com.fasterxml.jackson.databind.JsonNode]' available: 
expected single matching bean but found 2: slowVarsQueue,eventsQueue

The two beans has different names one is slowVarsQueue and the other is eventsQueue, why Spring complain ?