title: Error when broadcasting Joda DateTime in Spark
body: <p>When using Joda Time with Spark, the code below causes <code>java.lang.NullPointerException</code></p>
  
  <pre><code>val todayBroadcast = sc.broadcast(new DateTime())
  val dataRDD2 = dataRDD.filter(item =&gt; {
                                  todayBroadcast.value.minusMonths(1).isBefore(item._1)
                                })
  </code></pre>
  
  <p>On the other hand, the code below works with no issues</p>
  
  <pre><code>    val dataRDD2 = dataRDD.filter(item =&gt; {
                                      val today = new DateTime()
                                      today.minusMonths(1).isBefore(item._1)
                                    })
  </code></pre>