Hi,
I have setup the hadoop on single node and worked fine but when executing the wordcount example, following error is thornw, Is this any configuration issue? bin/hadoop jar hadoop-examples-0.20.2-cdh3u1.jar wordcount /user/hduser/testfiles /user/hduser/output 11/10/14 10:29:53 INFO input.FileInputFormat: Total input paths to process : 3 11/10/14 10:29:53 WARN snappy.LoadSnappy: Snappy native library is available 11/10/14 10:29:53 INFO util.NativeCodeLoader: Loaded the native-hadoop library 11/10/14 10:29:53 INFO snappy.LoadSnappy: Snappy native library loaded 11/10/14 10:29:53 INFO mapred.JobClient: Running job: job_201110141028_0001 11/10/14 10:29:54 INFO mapred.JobClient: map 0% reduce 0% 11/10/14 10:29:59 INFO mapred.JobClient: map 66% reduce 0% 11/10/14 10:30:01 INFO mapred.JobClient: Task Id : attempt_201110141028_0001_r_000000_0, Status : FAILED Error: java.lang.NullPointerException at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:768) at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.getMapCompletionEvents(ReduceTask.java:2824) at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.run(ReduceTask.java:2744) 11/10/14 10:30:02 INFO mapred.JobClient: map 100% reduce 0% 11/10/14 10:30:03 INFO mapred.JobClient: Task Id : attempt_201110141028_0001_r_000000_1, Status : FAILED Error: java.lang.NullPointerException at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:768) at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.getMapCompletionEvents(ReduceTask.java:2824) at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.run(ReduceTask.java:2744) 11/10/14 10:30:05 INFO mapred.JobClient: Task Id : attempt_201110141028_0001_r_000000_2, Status : FAILED Error: java.lang.NullPointerException at java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:768) at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.getMapCompletionEvents(ReduceTask.java:2824) at org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.run(ReduceTask.java:2744) 11/10/14 10:30:08 INFO mapred.JobClient: Job complete: job_201110141028_0001 11/10/14 10:30:08 INFO mapred.JobClient: Counters: 18 11/10/14 10:30:08 INFO mapred.JobClient: Job Counters 11/10/14 10:30:08 INFO mapred.JobClient: Launched reduce tasks=4 11/10/14 10:30:08 INFO mapred.JobClient: SLOTS_MILLIS_MAPS=9167 11/10/14 10:30:08 INFO mapred.JobClient: Total time spent by all reduces waiting after reserving slots (ms)=0 11/10/14 10:30:08 INFO mapred.JobClient: Total time spent by all maps waiting after reserving slots (ms)=0 11/10/14 10:30:08 INFO mapred.JobClient: Launched map tasks=3 11/10/14 10:30:08 INFO mapred.JobClient: Data-local map tasks=3 11/10/14 10:30:08 INFO mapred.JobClient: Failed reduce tasks=1 11/10/14 10:30:08 INFO mapred.JobClient: SLOTS_MILLIS_REDUCES=3292 11/10/14 10:30:08 INFO mapred.JobClient: FileSystemCounters 11/10/14 10:30:08 INFO mapred.JobClient: FILE_BYTES_READ=740427 11/10/14 10:30:08 INFO mapred.JobClient: HDFS_BYTES_READ=2863597 11/10/14 10:30:08 INFO mapred.JobClient: FILE_BYTES_WRITTEN=2161157 11/10/14 10:30:08 INFO mapred.JobClient: Map-Reduce Framework 11/10/14 10:30:08 INFO mapred.JobClient: Combine output records=87431 11/10/14 10:30:08 INFO mapred.JobClient: Map input records=58570 11/10/14 10:30:08 INFO mapred.JobClient: Spilled Records=138742 11/10/14 10:30:08 INFO mapred.JobClient: Map output bytes=4774081 11/10/14 10:30:08 INFO mapred.JobClient: Combine input records=487561 11/10/14 10:30:08 INFO mapred.JobClient: Map output records=487561 11/10/14 10:30:08 INFO mapred.JobClient: SPLIT_RAW_BYTES=361 -- View this message in context: http://old.nabble.com/wordcount-example-throwing-null-pointer-with-ConcurrentHashMap-tp32650178p32650178.html Sent from the Hadoop core-user mailing list archive at Nabble.com.