Hi,   I faced EXACT same issue. to fix this use  conf.registerKryoClasses(Array(classOf[ArrayBuffer[String]], classOf[ListBuffer[String]])) in your code. However, you won't get an error but may be incorrect results. I say incorrect because, for some minsupport values it runs fine but for many others it isn't, especially if the support value is low.   I would recommend you to use Java serializer despite it being inefficient. If you could upgrade to spark 1.5.2 or 1.6 it is even better, as some bug fixes have been made in these newer versions.   Here is a link on serialization:   http://spark.apache.org/docs/latest/tuning.html#data-serialization     ... View more