Is does not seem to be safe to call RDD.firstParent from anywhere, as it might throw a java.util.NoSuchElementException: "head of empty list". This seems to be a bug for a consumer of the RDD API.
Zvara Zoltán mail, hangout, skype: zoltan.zv...@gmail.com mobile, viber: +36203129543 bank: 10918001-00000021-50480008 address: Hungary, 2475 Kápolnásnyék, Kossuth 6/a elte: HSKSJZ (ZVZOAAI.ELTE)
