title: Overloaded method value createDirectStream in error Spark Streaming
body: <p>When making the call </p>
  
  <pre><code>val kafkaParams: Map[String, String] =...
  var topic: String = ..
  val input2 = KafkaUtils.createDirectStream[String, String, StringDecoder, StringDecoder](ssc, kafkaParams, topic.toSet)
  </code></pre>
  
  <p>I get the error:</p>
  
  <blockquote>
    <p>overloaded method value createDirectStream with alternatives: (jssc:
    org.apache.spark.streaming.api.java.JavaStreamingContext,keyClass:
    Class[String],valueClass: Class[String],keyDecoderClass:
    Class[kafka.serializer.StringDecoder],valueDecoderClass:
    Class[kafka.serializer.StringDecoder],kafkaParams:
    java.util.Map[String,String],topics:
    java.util.Set[String])org.apache.spark.streaming.api.java.JavaPairInputDStream[String,String]
     (ssc: org.apache.spark.streaming.StreamingContext,kafkaParams:
    scala.collection.immutable.Map[String,String],topics:
    scala.collection.immutable.Set[String])(implicit evidence$19:
    scala.reflect.ClassTag[String], implicit evidence$20:
    scala.reflect.ClassTag[String], implicit evidence$21:
    scala.reflect.ClassTag[kafka.serializer.StringDecoder], implicit
    evidence$22:
    scala.reflect.ClassTag[kafka.serializer.StringDecoder])org.apache.spark.streaming.dstream.InputDStream[(String,
    String)] cannot be applied to
    (org.apache.spark.streaming.StreamingContext,
    scala.collection.immutable.Map[String,String],
    scala.collection.immutable.Set[Char])</p>
  </blockquote>
  
  <p>I also get a similar error when calling the parameterised version of createStream. </p>
  
  <p>Any idea what's the issue? </p>