title: Spark difference between maven Artifacts spark-core_2.10 and spark-core_2.11
body: <p>Does anyone know the difference between the two spark core artifacts?
  Both support Spark up to version 1.5.1. However, I alawys end up with the same error when using spark-core_2.11 in my Java application and trying to connect to the standalone cluster(Spark-1.5.1) with the spark url (spark://masterIP:Port)</p>
  
  <pre><code>WARN ReliableDeliverySupervisor: Association with remote system [akka.tcp://sparkMaster@192.168.188.20:7077] has failed, address is now gated for [5000] ms. Reason: [Disassociated] 
  ERROR SparkUncaughtExceptionHandler: Uncaught exception in thread Thread[appclient-registration-retry-thread,5,main]
  </code></pre>
  
  <p>The Master also logs a compability problem in its logs:</p>
  
  <pre><code>ERROR Remoting: org.apache.spark.deploy.DeployMessages$RegisterApplication; local class incompatible: stream classdesc serialVersionUID = 352674063933172066, local class serialVersionUID = -5495080032843259921
  java.io.InvalidClassException: org.apache.spark.deploy.DeployMessages$RegisterApplication; local class incompatible: stream classdesc serialVersionUID = 352674063933172066, local class serialVersionUID = -5495080032843259921
      at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:621)
      at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1623)
      at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1518)
      at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1774)
      at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1351)
      at java.io.ObjectInputStream.readObject(ObjectInputStream.java:371)
      at akka.serialization.JavaSerializer$$anonfun$1.apply(Serializer.scala:136)
      at scala.util.DynamicVariable.withValue(DynamicVariable.scala:57)
      at akka.serialization.JavaSerializer.fromBinary(Serializer.scala:136)
      at akka.serialization.Serialization$$anonfun$deserialize$1.apply(Serialization.scala:104)
      at scala.util.Try$.apply(Try.scala:161)
      at akka.serialization.Serialization.deserialize(Serialization.scala:98)
      at akka.remote.serialization.MessageContainerSerializer.fromBinary(MessageContainerSerializer.scala:63)
      at akka.serialization.Serialization$$anonfun$deserialize$1.apply(Serialization.scala:104)
      at scala.util.Try$.apply(Try.scala:161)
      at akka.serialization.Serialization.deserialize(Serialization.scala:98)
      at akka.remote.MessageSerializer$.deserialize(MessageSerializer.scala:23)
      at akka.remote.DefaultMessageDispatcher.payload$lzycompute$1(Endpoint.scala:58)
      at akka.remote.DefaultMessageDispatcher.payload$1(Endpoint.scala:58)
      at akka.remote.DefaultMessageDispatcher.dispatch(Endpoint.scala:76)
      at akka.remote.EndpointReader$$anonfun$receive$2.applyOrElse(Endpoint.scala:935)
      at akka.actor.Actor$class.aroundReceive(Actor.scala:467)
      at akka.remote.EndpointActor.aroundReceive(Endpoint.scala:411)
      at akka.actor.ActorCell.receiveMessage(ActorCell.scala:516)
      at akka.actor.ActorCell.invoke(ActorCell.scala:487)
      at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:238)
      at akka.dispatch.Mailbox.run(Mailbox.scala:220)
      at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:397)
      at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
      at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
      at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
      at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
  </code></pre>
  
  <p>When using spark-core_2.10 everything works fine.</p>