title: spring kafka thorws InstanceAlreadyExistsException exception after setting concurrency > 1
body: <p>I'm using spring-kafka, everything is working if I don't set the concurrency of ConcurrentKafkaListenerContainerFactory, when I set it to a number greater than 1, I get an exception: </p>
  
  <blockquote>
    <p>javax.management.InstanceAlreadyExistsException:
    kafka.consumer:type=app-info,id=client-3</p>
  </blockquote>
  
  <p>My config:</p>
  
  <pre><code>@Bean
  public ConcurrentKafkaListenerContainerFactory&lt;String, String&gt; 
      kafkaListenerContainerFactory() {
      ConcurrentKafkaListenerContainerFactory&lt;String, String&gt; factory = new 
      ConcurrentKafkaListenerContainerFactory&lt;String, String&gt;();
  
      factory.setConcurrency(kafkaConfig.getConcurrency());
  
      factory.getContainerProperties().setAckMode(AckMode.MANUAL);
      factory.setConsumerFactory(consumerFactory());
      return factory;
  }
  </code></pre>
  
  <p>properties:</p>
  
  <pre><code>kafka.enable-auto-commit=false
  
  kafka.client-id=client-1
  
  kafka.concurrency=2
  </code></pre>