title: Spring boot spring.kafka.bootstrap-servers not getting picked up by consumer config
body: <p>I'm trying to use connect a spring boot project to kafka .
  In my application.properties file I have the following configs:</p>
  
  <pre><code>spring.kafka.producer.key-serializer=org.apache.kafka.common.serialization.StringSerializer
  spring.kafka.producer.value-serializer=org.springframework.kafka.support.serializer.JsonSerializer
  spring.kafka.consumer.key-serializer=org.apache.kafka.common.serialization.StringSerializer
  spring.kafka.consumer.value-serializer=org.springframework.kafka.support.serializer.JsonSerializer
  spring.kafka.template.default-topic=my_default_topic
  spring.kafka.admin.fail-fast=true
  spring.kafka.consumer.auto-offset-reset=latest
  spring.kafka.consumer.group-id=my_group_id
  spring.kafka.listener.concurrency=10
  spring.kafka.bootstrap-servers=kafka:9092
  </code></pre>
  
  <p>But in the logs I see that only some of these values are making it into the consume configs. Configs from the logs are here:</p>
  
  <pre><code>2018-08-01 15:20:34.640  WARN 1 --- [           main] s.c.a.AnnotationConfigApplicationContext : Exception encountered during context initialization - cancelling refr[3/5548]
  mpt: org.springframework.context.ApplicationContextException: Failed to start bean 'org.springframework.kafka.config.internalKafkaListenerEndpointRegistry'; nested exception is org.apache.kafka.common.KafkaException: Failed to cons[2/5548]
  fka consumer                                                                                                                                                                                                                           [1/5548]
          isolation.level = read_uncommitted                                                                                                                            [46/5548]
          key.deserializer = class org.apache.kafka.common.serialization.StringDeserializer                                                                             [45/5548]
          max.partition.fetch.bytes = 1048576                                                                                                                           [44/5548]
          max.poll.interval.ms = 300000                                                                                                                                 [43/5548]
          check.crcs = true                                                                                                                                             [58/5548]
          client.id =
          connections.max.idle.ms = 540000
          enable.auto.commit = true
          exclude.internal.topics = true
          fetch.max.bytes = 52428800
          fetch.max.wait.ms = 500
          fetch.min.bytes = 1
          group.id = null
          heartbeat.interval.ms = 3000
          interceptor.classes = null
          internal.leave.group.on.close = true
          isolation.level = read_uncommitted
          key.deserializer = class org.apache.kafka.common.serialization.StringDeserializer
          max.partition.fetch.bytes = 1048576
          max.poll.interval.ms = 300000
          max.poll.records = 500
          metadata.max.age.ms = 300000
          metric.reporters = []
          metrics.num.samples = 2
          metrics.recording.level = INFO
          metrics.sample.window.ms = 30000
          partition.assignment.strategy = [class org.apache.kafka.clients.consumer.RangeAssignor]
          receive.buffer.bytes = 65536
          reconnect.backoff.max.ms = 1000
          reconnect.backoff.ms = 50
          request.timeout.ms = 305000
          retry.backoff.ms = 100
          sasl.jaas.config = null
          sasl.kerberos.kinit.cmd = /usr/bin/kinit
          sasl.kerberos.min.time.before.relogin = 60000
          sasl.kerberos.service.name = null
          sasl.kerberos.ticket.renew.jitter = 0.05
          sasl.kerberos.ticket.renew.window.factor = 0.8
          sasl.mechanism = GSSAPI
          security.protocol = PLAINTEXT
          send.buffer.bytes = 131072
          session.timeout.ms = 10000
          ssl.cipher.suites = null
          ssl.enabled.protocols = [TLSv1.2, TLSv1.1, TLSv1]
          ssl.endpoint.identification.algorithm = null
          ssl.key.password = null
          ssl.keymanager.algorithm = SunX509
          ssl.keystore.location = null
          ssl.keystore.password = null
          ssl.keystore.type = JKS
          ssl.protocol = TLS
          ssl.provider = null
          ssl.secure.random.implementation = null
          ssl.trustmanager.algorithm = PKIX
          ssl.truststore.location = null
          ssl.truststore.password = null
          ssl.truststore.type = JKS
          value.deserializer = class org.springframework.kafka.support.serializer.JsonDeserializer
  </code></pre>
  
  <p>Specifically bootstrap.servers and group.id are missing. I then get an exception</p>
  
  <pre><code> org.springframework.context.ApplicationContextException: Failed to start bean 'org.springframework.kafka.config.internalKafkaListenerEndpointRegistry'; nested exception is or
  g.apache.kafka.common.KafkaException: Failed to construct kafka consumer
  </code></pre>
  
  <p>because it can't find the bootstrap servers. I know I can manually pass the properties into a <code>DefaultKafkaConsumerFactory</code> bean but I was hoping Spring Boot could handle that automatically. Is there any way to do that?
  Thank you!</p>
  
  <p><strong>EDIT:</strong>
  I am trying to consume the messages using a <code>@KafkaListener</code> like so...</p>
  
  <pre><code> @KafkaListener(topics = "${app-name.inputTopic}")
      public void handleMessage(CustomMessage message){ 
         //my code
      }
  </code></pre>