我遵循Druid网站上的步骤：http://druid.io/docs/latest/tutorials/quickstart.html
但出于某种原因，它总是给我这个错误：

2016-07-19T22:44:36,276 ERROR [task-runner-0-priority-0] io.druid.indexing.overlord.ThreadPoolTaskRunner - Exception while running task[HadoopIndexTask{id=index_hadoop_wikiticker_2016-07-19T22:44:25.500Z, type=index_hadoop, dataSource=wikiticker}]
java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
    at com.google.common.base.Throwables.propagate(Throwables.java:160) ~[guava-16.0.1.jar:?]
    at io.druid.indexing.common.task.HadoopTask.invokeForeignLoader(HadoopTask.java:204) ~[druid-indexing-service-0.9.1.1.jar:0.9.1.1]
    at io.druid.indexing.common.task.HadoopIndexTask.run(HadoopIndexTask.java:208) ~[druid-indexing-service-0.9.1.1.jar:0.9.1.1]
    at io.druid.indexing.overlord.ThreadPoolTaskRunner$ThreadPoolTaskRunnerCallable.call(ThreadPoolTaskRunner.java:436) [druid-indexing-service-0.9.1.1.jar:0.9.1.1]
    at io.druid.indexing.overlord.ThreadPoolTaskRunner$ThreadPoolTaskRunnerCallable.call(ThreadPoolTaskRunner.java:408) [druid-indexing-service-0.9.1.1.jar:0.9.1.1]
    at java.util.concurrent.FutureTask.run(FutureTask.java:262) [?:1.7.0_79]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [?:1.7.0_79]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [?:1.7.0_79]
    at java.lang.Thread.run(Thread.java:745) [?:1.7.0_79]
Caused by: java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0_79]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[?:1.7.0_79]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.7.0_79]
    at java.lang.reflect.Method.invoke(Method.java:606) ~[?:1.7.0_79]
    at io.druid.indexing.common.task.HadoopTask.invokeForeignLoader(HadoopTask.java:201) ~[druid-indexing-service-0.9.1.1.jar:0.9.1.1]
    ... 7 more
Caused by: com.metamx.common.ISE: Job[class io.druid.indexer.IndexGeneratorJob] failed!
    at io.druid.indexer.JobHelper.runJobs(JobHelper.java:343) ~[druid-indexing-hadoop-0.9.1.1.jar:0.9.1.1]
    at io.druid.indexer.HadoopDruidIndexerJob.run(HadoopDruidIndexerJob.java:94) ~[druid-indexing-hadoop-0.9.1.1.jar:0.9.1.1]
    at io.druid.indexing.common.task.HadoopIndexTask$HadoopIndexGeneratorInnerProcessing.runTask(HadoopIndexTask.java:261) ~[druid-indexing-service-0.9.1.1.jar:0.9.1.1]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0_79]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[?:1.7.0_79]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.7.0_79]
    at java.lang.reflect.Method.invoke(Method.java:606) ~[?:1.7.0_79]
    at io.druid.indexing.common.task.HadoopTask.invokeForeignLoader(HadoopTask.java:201) ~[druid-indexing-service-0.9.1.1.jar:0.9.1.1]
    ... 7 more

有人知道原因吗？即使我去控制台：http://localhost：8090/console.html它表示我的摄取失败。