title: Spark + Cassandra connector fails with LocalNodeFirstLoadBalancingPolicy.close()
body: <p>I've been trying to connect cassandra with Spark in scala but I've been facing a couple of issues.
  Here are the versions used :</p>
  
  <pre><code>    Spark 1.5.0
      Cassandra 2.1.9
      Scala 2.11.1
  </code></pre>
  
  <p>Here are the steps I followed:
  - Downloaded Cassandra with the default configurations and I started it via bin/cassandra -f. Cassandra starts well and listens on 127.0.0.1
  - I added some mock data into the try table in the spark keyspace.
  - Downloaded Spark and started the master via sbin/start-master.sh. I can see on localhost:8888 that the master is running well
  - I wrote the following build.sbt :</p>
  
  <pre><code>val sparkVersion = "1.5.0"
  
  libraryDependencies ++= Seq(
    jdbc,
    anorm,
    cache,
    ws,
    "org.scalatest" % "scalatest_2.11" % "3.0.0-M8",
    "com.typesafe" % "scalalogging-slf4j_2.10" % "1.1.0",
    "com.typesafe.scala-logging" %% "scala-logging" % "3.1.0",
    "org.apache.spark" % "spark-core_2.11" % sparkVersion,
    "org.apache.spark" % "spark-streaming_2.11" % sparkVersion,
    "org.apache.spark" % "spark-streaming-twitter_2.11" % sparkVersion,
    "org.apache.spark" %% "spark-streaming-kafka" % sparkVersion,
    "org.apache.spark" % "spark-sql_2.11" % sparkVersion,
    "com.datastax.cassandra" % "cassandra-driver-core" % "3.0.0-alpha2",
    "com.datastax.spark" %% "spark-cassandra-connector" % "1.5.0-M1",
    "org.scalatest" %% "scalatest" % "2.2.1" % "test",
    "org.mockito" % "mockito-all" % "1.9.5" % "test"
  )
  </code></pre>
  
  <ul>
  <li><p>I wrote the following Main :</p>
  
  <pre><code>val conf = new SparkConf(true)
  .setAppName("Test")
  .setMaster("spark://127.0.0.1:7077")
  .set("spark.cassandra.connection.host","127.0.0.1")
  .set("spark.cassandra.connection.port", "9042")
  .set("spark.driver.allowMultipleContexts", "true")
  
  /** Connect to the Spark cluster: */
  lazy val sc = new SparkContext(conf)
  
  val rdd = sc.cassandraTable("spark", "try")
  val file_collect=rdd.collect()
  file_collect.map(println(_))
  
  sc.stop()
  </code></pre></li>
  <li><p>Then I run the program.</p></li>
  </ul>
  
  <p>Here is the stack trace I get with "spark.cassandra.connector.host" = "spark://127.0.0.1:7077".</p>
  
  <pre><code>[error] o.a.s.u.SparkUncaughtExceptionHandler - Uncaught exception in thread Thread[appclient-registration-retry-thread,5,main]
  java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.FutureTask@b6391a7 rejected from java.util.concurrent.ThreadPoolExecutor@7f56044a[Running, pool size = 1, active threads = 0, queued tasks = 0, completed tasks = 3]
      at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2047) ~[na:1.8.0_60]
      at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:823) [na:1.8.0_60]
      at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1369) [na:1.8.0_60]
      at java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:112) ~[na:1.8.0_60]
      at org.apache.spark.deploy.client.AppClient$ClientEndpoint$$anonfun$tryRegisterAllMasters$1.apply(AppClient.scala:96) ~[spark-core_2.11-1.5.0.jar:1.5.0]
  </code></pre>
  
  <p>If I change this parameter to local[*], then I get this stack trace:</p>
  
  <pre><code>play.api.Application$$anon$1: Execution exception[[RuntimeException: java.lang.AbstractMethodError: com.datastax.spark.connector.cql.LocalNodeFirstLoadBalancingPolicy.close()V]]
      at play.api.Application$class.handleError(Application.scala:296) ~[play_2.11-2.3.8.jar:2.3.8]
      at play.api.DefaultApplication.handleError(Application.scala:402) [play_2.11-2.3.8.jar:2.3.8]
      at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3$$anonfun$applyOrElse$4.apply(PlayDefaultUpstreamHandler.scala:320) [play_2.11-2.3.8.jar:2.3.8]
      at play.core.server.netty.PlayDefaultUpstreamHandler$$anonfun$3$$anonfun$applyOrElse$4.apply(PlayDefaultUpstreamHandler.scala:320) [play_2.11-2.3.8.jar:2.3.8]
      at scala.Option.map(Option.scala:146) [scala-library-2.11.7.jar:na]
  Caused by: java.lang.RuntimeException: java.lang.AbstractMethodError: com.datastax.spark.connector.cql.LocalNodeFirstLoadBalancingPolicy.close()V
      at play.api.mvc.ActionBuilder$$anon$1.apply(Action.scala:523) ~[play_2.11-2.3.8.jar:2.3.8]
      at play.api.mvc.Action$$anonfun$apply$1$$anonfun$apply$4$$anonfun$apply$5.apply(Action.scala:130) ~[play_2.11-2.3.8.jar:2.3.8]
      at play.api.mvc.Action$$anonfun$apply$1$$anonfun$apply$4$$anonfun$apply$5.apply(Action.scala:130) ~[play_2.11-2.3.8.jar:2.3.8]
      at play.utils.Threads$.withContextClassLoader(Threads.scala:21) ~[play_2.11-2.3.8.jar:2.3.8]
      at play.api.mvc.Action$$anonfun$apply$1$$anonfun$apply$4.apply(Action.scala:129) ~[play_2.11-2.3.8.jar:2.3.8]
  Caused by: java.lang.AbstractMethodError: com.datastax.spark.connector.cql.LocalNodeFirstLoadBalancingPolicy.close()V
      at com.datastax.driver.core.Cluster$Manager.close(Cluster.java:1423) ~[cassandra-driver-core-3.0.0-alpha2.jar:na]
      at com.datastax.driver.core.Cluster$Manager.access$200(Cluster.java:1171) ~[cassandra-driver-core-3.0.0-alpha2.jar:na]
      at com.datastax.driver.core.Cluster.closeAsync(Cluster.java:462) ~[cassandra-driver-core-3.0.0-alpha2.jar:na]
      at com.datastax.driver.core.Cluster.close(Cluster.java:473) ~[cassandra-driver-core-3.0.0-alpha2.jar:na]
      at com.datastax.spark.connector.cql.CassandraConnector$.com$datastax$spark$connector$cql$CassandraConnector$$createSession(CassandraConnector.scala:163) ~[spark-cassandra-connector_2.11-1.5.0-M1.jar:1.5.0-M1]
  </code></pre>
  
  <p>Any idea where the problem comes from?</p>