title: Kafka Producer - org.apache.kafka.common.serialization.StringSerializer could not be found
body: <p>I have creating a simple Kafka Producer &amp; Consumer.I am using kafka_2.11-0.9.0.0. Here is my Producer code.</p>
  
  <pre><code>public class KafkaProducerTest {
  public static String topicName = "test-topic-2";
  public static void main(String[] args) {
      // TODO Auto-generated method stub
      Properties props = new Properties();
      props.put("bootstrap.servers", "localhost:9092");
      props.put("acks", "all");
      props.put("retries", 0);
      props.put("batch.size", 16384);
      props.put("linger.ms", 1);
      props.put("buffer.memory", 33554432);
      props.put("key.serializer",
              StringSerializer.class.getName());
      props.put("value.serializer",
              StringSerializer.class.getName());
  
      Producer&lt;String, String&gt; producer = new KafkaProducer(props);
      for (int i = 0; i &lt; 100; i++) {
          ProducerRecord&lt;String, String&gt; producerRecord = new ProducerRecord&lt;String, String&gt;(
                  topicName, Integer.toString(i), Integer.toString(i));
          System.out.println(producerRecord);
          producer.send(producerRecord);
      }
  
      producer.close();
  }
  
  }
  </code></pre>
  
  <p>While starting the bundle I a facing the below error:</p>
  
  <pre><code>2016-05-20 09:44:57,792 | ERROR | nsole user karaf | ShellUtil                        | 44 - org.apache.karaf.shell.core - 4.0.3 | Exception caught while executing command
  org.apache.karaf.shell.support.MultiException: Error executing command on bundles:
      Error starting bundle162: Activator start error in bundle NewKafkaArtifact [162].
      at org.apache.karaf.shell.support.MultiException.throwIf(MultiException.java:61)
      at org.apache.karaf.bundle.command.BundlesCommand.doExecute(BundlesCommand.java:69)[24:org.apache.karaf.bundle.core:4.0.3]
      at org.apache.karaf.bundle.command.BundlesCommand.execute(BundlesCommand.java:54)[24:org.apache.karaf.bundle.core:4.0.3]
      at org.apache.karaf.shell.impl.action.command.ActionCommand.execute(ActionCommand.java:83)[44:org.apache.karaf.shell.core:4.0.3]
      at org.apache.karaf.shell.impl.console.osgi.secured.SecuredCommand.execute(SecuredCommand.java:67)[44:org.apache.karaf.shell.core:4.0.3]
      at org.apache.karaf.shell.impl.console.osgi.secured.SecuredCommand.execute(SecuredCommand.java:87)[44:org.apache.karaf.shell.core:4.0.3]
      at org.apache.felix.gogo.runtime.Closure.executeCmd(Closure.java:480)[44:org.apache.karaf.shell.core:4.0.3]
      at org.apache.felix.gogo.runtime.Closure.executeStatement(Closure.java:406)[44:org.apache.karaf.shell.core:4.0.3]
      at org.apache.felix.gogo.runtime.Pipe.run(Pipe.java:108)[44:org.apache.karaf.shell.core:4.0.3]
      at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:182)[44:org.apache.karaf.shell.core:4.0.3]
      at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:119)[44:org.apache.karaf.shell.core:4.0.3]
      at org.apache.felix.gogo.runtime.CommandSessionImpl.execute(CommandSessionImpl.java:94)[44:org.apache.karaf.shell.core:4.0.3]
      at org.apache.karaf.shell.impl.console.ConsoleSessionImpl.run(ConsoleSessionImpl.java:270)[44:org.apache.karaf.shell.core:4.0.3]
      at java.lang.Thread.run(Thread.java:745)[:1.8.0_66]
  Caused by: java.lang.Exception: Error starting bundle162: Activator start error in bundle NewKafkaArtifact [162].
      at org.apache.karaf.bundle.command.BundlesCommand.doExecute(BundlesCommand.java:66)[24:org.apache.karaf.bundle.core:4.0.3]
      ... 12 more
  Caused by: org.osgi.framework.BundleException: Activator start error in bundle NewKafkaArtifact [162].
      at org.apache.felix.framework.Felix.activateBundle(Felix.java:2276)[org.apache.felix.framework-5.4.0.jar:]
      at org.apache.felix.framework.Felix.startBundle(Felix.java:2144)[org.apache.felix.framework-5.4.0.jar:]
      at org.apache.felix.framework.BundleImpl.start(BundleImpl.java:998)[org.apache.felix.framework-5.4.0.jar:]
      at org.apache.karaf.bundle.command.Start.executeOnBundle(Start.java:38)[24:org.apache.karaf.bundle.core:4.0.3]
      at org.apache.karaf.bundle.command.BundlesCommand.doExecute(BundlesCommand.java:64)[24:org.apache.karaf.bundle.core:4.0.3]
      ... 12 more
  Caused by: org.apache.kafka.common.config.ConfigException: Invalid value org.apache.kafka.common.serialization.StringSerializer for configuration key.serializer: Class org.apache.kafka.common.serialization.StringSerializer could not be found.
      at org.apache.kafka.common.config.ConfigDef.parseType(ConfigDef.java:255)[141:kafka-examples:1.0.0.SNAPSHOT-jar-with-dependencies]
      at org.apache.kafka.common.config.ConfigDef.parse(ConfigDef.java:145)[141:kafka-examples:1.0.0.SNAPSHOT-jar-with-dependencies]
      at org.apache.kafka.common.config.AbstractConfig.&lt;init&gt;(AbstractConfig.java:49)[141:kafka-examples:1.0.0.SNAPSHOT-jar-with-dependencies]
      at org.apache.kafka.common.config.AbstractConfig.&lt;init&gt;(AbstractConfig.java:56)[141:kafka-examples:1.0.0.SNAPSHOT-jar-with-dependencies]
      at org.apache.kafka.clients.producer.ProducerConfig.&lt;init&gt;(ProducerConfig.java:317)[141:kafka-examples:1.0.0.SNAPSHOT-jar-with-dependencies]
      at org.apache.kafka.clients.producer.KafkaProducer.&lt;init&gt;(KafkaProducer.java:181)[141:kafka-examples:1.0.0.SNAPSHOT-jar-with-dependencies]
      at com.NewKafka.NewKafkaArtifact.KafkaProducerTest.main(KafkaProducerTest.java:25)[162:NewKafkaArtifact:0.0.1.SNAPSHOT]
      at com.NewKafka.NewKafkaArtifact.StartKafka.start(StartKafka.java:11)[162:NewKafkaArtifact:0.0.1.SNAPSHOT]
      at org.apache.felix.framework.util.SecureAction.startActivator(SecureAction.java:697)[org.apache.felix.framework-5.4.0.jar:]
      at org.apache.felix.framework.Felix.activateBundle(Felix.java:2226)[org.apache.felix.framework-5.4.0.jar:]
      ... 16 more
  </code></pre>
  
  <p>I have tried setting the <code>key.serializer</code> and <code>value.serializer</code> like below:</p>
  
  <pre><code>props.put("key.serializer",StringSerializer.class.getName());
  props.put("value.serializer",StringSerializer.class.getName());
  </code></pre>
  
  <p>Also like, But still getting the same error. What is I am doing wrong here.</p>
  
  <pre><code>props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
  props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
  </code></pre>