title: how to validate connection strings of azure iot hub in spark streaming?
body: <p>i'm new to azure iot hub . im trying to pull message from azure iot hub using spark streaming . im getting error when i execute the code and i could understand there is some problem in connection strings. is there any specific way to validate the connection string in spark and also please tell me the format which i specified is correct or not .</p>
  
  <p>My sample code:</p>
  
  <pre><code>import org.apache.spark.eventhubs._
  
  val eventHubName = "xyztest.azure-devices.net"
  val eventHubNSConnStr = "Endpoint=sb://testname.servicebus.windows.net/;SharedAccessKeyName=primary;SharedAccessKey=abcedfgrdxyeurjrsdfyasdf="
  val connStr = ConnectionStringBuilder(eventHubNSConnStr).setEventHubName(eventHubName).build 
  val customEventhubParameters = EventHubsConf(connStr).setMaxEventsPerTrigger(5)
  val incomingStream = spark.readStream.format("eventhubs").options(customEventhubParameters.toMap).load()
  incomingStream.writeStream.outputMode("append").format("console").option("truncate", false).start().awaitTermination()
  </code></pre>
  
  <p>Errro:</p>
  
  <pre><code>java.util.concurrent.ExecutionException: com.microsoft.azure.eventhubs.IllegalEntityException: The messaging entity 'sb://testname.servicebus.windows.net/xyztest' could not be found.
          at java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:357)
          at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:1895)
          at org.apache.spark.eventhubs.client.EventHubsClient.partitionCount(EventHubsClient.scala:169)
  </code></pre>