spark streaming接收多个tcp源

spark streaming支持一个JavaStreamingContext接收多个socket源吗？我在代码中这样写：
JavaReceiverInputDStream<String> lines = jssc.socketTextStream("10.129.10.101", 9999);
JavaReceiverInputDStream<String> lines2 = jssc.socketTextStream("10.129.10.102", 9999);
lines.union(lines2);

...
这样写执行会报错：
3283 [sparkDriver-akka.actor.default-dispatcher-2] ERROR akka.actor.OneForOneStrategy  -
java.lang.NullPointerException
        at org.apache.spark.streaming.DStreamGraph$$anonfun$getMaxInputStreamRememberDuration$2.apply(DStreamGraph.scala:168)
        at org.apache.spark.streaming.DStreamGraph$$anonfun$getMaxInputStreamRememberDuration$2.apply(DStreamGraph.scala:168)
        at scala.collection.TraversableOnce$$anonfun$maxBy$1.apply(TraversableOnce.scala:225)
        at scala.collection.IndexedSeqOptimized$class.foldl(IndexedSeqOptimized.scala:51)
        at scala.collection.IndexedSeqOptimized$class.reduceLeft(IndexedSeqOptimized.scala:68)
        at scala.collection.mutable.ArrayBuffer.reduceLeft(ArrayBuffer.scala:47)
        at scala.collection.TraversableOnce$class.maxBy(TraversableOnce.scala:225)
        at scala.collection.AbstractTraversable.maxBy(Traversable.scala:105)
        at org.apache.spark.streaming.DStreamGraph.getMaxInputStreamRememberDuration(DStreamGraph.scala:168)
        at org.apache.spark.streaming.scheduler.JobGenerator.clearMetadata(JobGenerator.scala:256)
        at org.apache.spark.streaming.scheduler.JobGenerator.org$apache$spark$streaming$scheduler$JobGenerator$$processEvent(JobGenerator.scala:168)
        at org.apache.spark.streaming.scheduler.JobGenerator$$anonfun$start$1$$anon$1$$anonfun$receive$1.applyOrElse(JobGenerator.scala:78)
        at akka.actor.Actor$class.aroundReceive(Actor.scala:465)
        at org.apache.spark.streaming.scheduler.JobGenerator$$anonfun$start$1$$anon$1.aroundReceive(JobGenerator.scala:76)
        at akka.actor.ActorCell.receiveMessage(ActorCell.scala:516)
        at akka.actor.ActorCell.invoke(ActorCell.scala:487)
        at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:238)
        at akka.dispatch.Mailbox.run(Mailbox.scala:220)
        at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:393)
        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)


请指教怎么可以接收多个tcp数据源。

把lines.union(lines2);改成下面
JavaReceiverInputDStream<String> union=lines.union(lines2);如果还不行，说明环境问题了

join操作会返回一个UnionDStream，我测试过了多数据源没问题的，我使用简单的netcat服务测试。首先我的代码如下：

object StreamingTest {   def main(args: Array[String]) {     val conf = new SparkConf().setMaster("spark://192.168.1.12:7077").setAppName("StreamingTest")      //val conf = new SparkConf().setMaster("local[4]").setAppName("NetworkWordCount")     val ssc = new StreamingContext(conf, Seconds(60))     // Create a DStream that will connect to hostname:port, like localhost:9999     //监控socket端口接收数据     val socket1 = ssc.socketTextStream("192.168.1.12", 6781)     val socket2 = ssc.socketTextStream("192.168.1.12",6782)     val sockets = socket1.union(socket2)     sockets.print()     ssc.start()     ssc.awaitTermination()   } }

代码中从192.168.1.12的6781和6782两个端口接收数据，
使用nc -l 192.168.1.12 6781  和 nc -l 192.168.1.12 分别在两个console启动nc

[yun@master ~]$ nc -l 192.168.1.12 6782 aaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaa

[yun@master bin]$ nc -l 192.168.1.12 6781 bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb

然后输入内容回车自动输入
sparkStreaming成功接收到数据如下：

------------------------------------------- Time: 1450065720000 ms ------------------------------------------- bbbbbbbbbbbbbbbbbbbbbbbbbbbbbb aaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaaaaaaaaaaaaaaaa

还有就是你报的错“ [sparkDriver-akka.actor.default-dispatcher-2] ERROR akka.actor.OneForOneStrategy  -
java.lang.NullPointerException
        at ”明显时在Driver端报了一个null，你仔细检查一下你的代码中，是否可能有除先null错误的地方，如若不是，请仔细看看你的集群环境是否搭建好

感谢楼上两位的回答，问题解决了，按照下面这样写就对了。
JavaReceiverInputDStream<String> lines = jssc.socketTextStream("10.129.10.101", 9999);
JavaReceiverInputDStream<String> lines2 = jssc.socketTextStream("10.129.10.102", 9999);
JavaDStream<String> union = lines.union(lines2);