title: Serialization exception in HazelCast 3.5 with Scala
body: <p>I am using Hazelcast 3.5 with scala 
  i have a case class Abc i am trying to store object of my class in hazelcast from my client  but it gives me some serialization exception</p>
  
  <p>here is my class </p>
  
  <pre><code> @SerialVersionUID(1)
      case class Abc( id : Int ,name : String , subjectCode : MutableList[Int]) extends Serialable 
  </code></pre>
  
  <p>when i run the client code it gives me following exception</p>
  
  <pre><code>18:33:43.274 [hz._hzInstance_1_dev.partition-operation.thread-1] ERROR c.h.map.impl.operation.PutOperation - [192.168.15.20]:5701 [dev] [3.5] java.lang.ClassNotFoundException: scala.collection.mutable.MutableList
  com.hazelcast.nio.serialization.HazelcastSerializationException: java.lang.ClassNotFoundException: scala.collection.mutable.MutableList
      at com.hazelcast.nio.serialization.DefaultSerializers$ObjectSerializer.read(DefaultSerializers.java:201) ~[hazelcast-3.5.jar:3.5]
      at com.hazelcast.nio.serialization.StreamSerializerAdapter.read(StreamSerializerAdapter.java:41) ~[hazelcast-3.5.jar:3.5]
      at com.hazelcast.nio.serialization.SerializationServiceImpl.toObject(SerializationServiceImpl.java:276) ~[hazelcast-3.5.jar:3.5]
      at com.hazelcast.map.impl.mapstore.AbstractMapDataStore.toObject(AbstractMapDataStore.java:78) ~[hazelcast-3.5.jar:3.5]
  </code></pre>