method getAllPools in SC throws NPE 

SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/home/wangfei/spark0403/spark-master/examples/target/scala-2.10/spark-examples_2.10-assembly-1.0.0-SNAPSHOT.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/home/wangfei/spark0403/spark-master/assembly/target/scala-2.10/spark-assembly_2.10-1.0.0-SNAPSHOT-hadoop2.3.0.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.slf4j.impl.Log4jLoggerFactory]
14/04/03 16:43:19 INFO SecurityManager: SecurityManager, is authentication enabled: false are ui acls enabled: false users with view permissions: Set(root)
14/04/03 16:43:19 INFO Slf4jLogger: Slf4jLogger started
14/04/03 16:43:19 INFO Remoting: Starting remoting
14/04/03 16:43:20 INFO Remoting: Remoting started; listening on addresses :[akka.tcp://spark@VM-13:55231]
14/04/03 16:43:20 INFO Remoting: Remoting now listens on addresses: [akka.tcp://spark@VM-13:55231]
14/04/03 16:43:20 INFO SparkEnv: Registering BlockManagerMaster
14/04/03 16:43:20 INFO DiskBlockManager: Created local directory at /tmp/spark-local-20140403164320-b637
14/04/03 16:43:20 INFO MemoryStore: MemoryStore started with capacity 1141.5 MB.
14/04/03 16:43:20 INFO ConnectionManager: Bound socket to port 33813 with id = ConnectionManagerId(VM-13,33813)
14/04/03 16:43:20 INFO BlockManagerMaster: Trying to register BlockManager
14/04/03 16:43:20 INFO BlockManagerInfo: Registering block manager VM-13:33813 with 1141.5 MB RAM
14/04/03 16:43:20 INFO BlockManagerMaster: Registered BlockManager
14/04/03 16:43:20 INFO HttpServer: Starting HTTP Server
14/04/03 16:43:21 INFO HttpBroadcast: Broadcast server started at http://9.91.11.32:58746
14/04/03 16:43:21 INFO SparkEnv: Registering MapOutputTracker
14/04/03 16:43:21 INFO HttpFileServer: HTTP File server directory is /tmp/spark-34b290f1-ca2f-489e-93c5-1c3e860874b0
14/04/03 16:43:21 INFO HttpServer: Starting HTTP Server
14/04/03 16:43:22 INFO SparkUI: Started Spark Web UI at http://VM-13:4040
14/04/03 16:43:22 WARN ServletHandler: /stages/
java.lang.NullPointerException
        at org.apache.spark.SparkContext.getAllPools(SparkContext.scala:712)
        at org.apache.spark.ui.jobs.IndexPage.render(IndexPage.scala:50)
        at org.apache.spark.ui.jobs.JobProgressUI$$anonfun$getHandlers$3.apply(JobProgressUI.scala:58)
        at org.apache.spark.ui.jobs.JobProgressUI$$anonfun$getHandlers$3.apply(JobProgressUI.scala:58)
        at org.apache.spark.ui.JettyUtils$$anon$1.doGet(JettyUtils.scala:68)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
        at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:684)
        at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:501)
        at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1086)
        at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:428)
        at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1020)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
        at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:255)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
        at org.eclipse.jetty.server.Server.handle(Server.java:370)
        at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:494)
        at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:971)
        at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:1033)
        at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:644)
        at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235)
        at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:667)
        at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:52)
        at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
        at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
        at java.lang.Thread.run(Thread.java:662)