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Re: Secondary Sort example error
Harsh J 2013-02-07, 18:49
The JIRA https://issues.apache.org/jira/browse/MAPREDUCE-2584 should
help such cases, if what I speculated above is indeed the case.

On Fri, Feb 8, 2013 at 12:16 AM, Harsh J <[EMAIL PROTECTED]> wrote:
> Thanks, I managed to correlate proper line numbers.
>
> Are you using some form of custom serialization in your job code? That
> is, are your keys non-Writable types and are of some other type? The
> specific NPE is arising from the SerializationFactory not being able
> to find a serializer for your Map-Output key class. You may want to
> look into that direction, or share your code for the list to spot it
> instead.
>
> On Fri, Feb 8, 2013 at 12:11 AM, Ravi Chandran
> <[EMAIL PROTECTED]> wrote:
>> hi,
>>
>> it is Hadoop 2.0.0-cdh4.1.1. the whole output is given below:
>>
>> Hadoop 2.0.0-cdh4.1.1
>> Subversion
>> file:///data/1/jenkins/workspace/generic-package-centos32-6/topdir/BUILD/hadoop-2.0.0-cdh4.1.1/src/hadoop-common-project/hadoop-common
>> -r 581959ba23e4af85afd8db98b7687662fe9c5f20
>>
>>
>>
>> On Fri, Feb 8, 2013 at 12:04 AM, Harsh J <[EMAIL PROTECTED]> wrote:
>>>
>>> Hey Ravi,
>>>
>>> What version of Hadoop is this exactly? (Type and send output of
>>> "hadoop version" if unsure)
>>>
>>> On Thu, Feb 7, 2013 at 11:55 PM, Ravi Chandran
>>> <[EMAIL PROTECTED]> wrote:
>>> > Hi,
>>> >
>>> > I am trying to do a name sorting using secondary sort. I have a working
>>> > example, which I am taking as a reference. But I am getting a null
>>> > pointer
>>> > error in the MapTask class. I am not able to locate the reason. as the
>>> > logic
>>> > to create the Custom Object from a given file has been tested through a
>>> > java
>>> > class..
>>> > I am getting this error:
>>> >
>>> > 13/02/07 12:23:42 WARN snappy.LoadSnappy: Snappy native library is
>>> > available
>>> > 13/02/07 12:23:42 INFO snappy.LoadSnappy: Snappy native library loaded
>>> > 13/02/07 12:23:42 INFO mapred.FileInputFormat: Total input paths to
>>> > process
>>> > : 1
>>> > 13/02/07 12:23:43 INFO mapred.JobClient: Running job:
>>> > job_201301301056_0014
>>> > 13/02/07 12:23:44 INFO mapred.JobClient:  map 0% reduce 0%
>>> > 13/02/07 12:23:56 INFO mapred.JobClient: Task Id :
>>> > attempt_201301301056_0014_m_000000_0, Status : FAILED
>>> > java.lang.NullPointerException
>>> >  at
>>> >
>>> > org.apache.hadoop.mapred.MapTask$MapOutputBuffer.<init>(MapTask.java:814)
>>> >  at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:385)
>>> >  at org.apache.hadoop.mapred.MapTask.run(MapTask.java:327)
>>> >  at org.apache.hadoop.mapred.Child$4.run(Child.java:268)
>>> >  at java.security.AccessController.doPrivileged(Native Method)
>>> >  at javax.security.auth.Subject.doAs(Subject.java:396)
>>> >  at
>>> >
>>> > org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1332)
>>> >  at org.apache.hadoop.mapred.Child.main(Child.java:262)
>>> > 13/02/07 12:23:57 INFO mapred.JobClient: Task Id :
>>> > attempt_201301301056_0014_m_000001_0, Status : FAILED
>>> > java.lang.NullPointerException
>>> >  at
>>> >
>>> > org.apache.hadoop.mapred.MapTask$MapOutputBuffer.<init>(MapTask.java:814)
>>> >  at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:385)
>>> >  at org.apache.hadoop.mapred.MapTask.run(MapTask.java:327)
>>> >  at org.apache.hadoop.mapred.Child$4.run(Child.java:268)
>>> >  at java.security.AccessController.doPrivileged(Native Method)
>>> >  at javax.security.auth.Subject.doAs(Subject.java:396)
>>> >  at
>>> >
>>> > org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1332)
>>> >  at org.apache.hadoop.mapred.Child.main(Child.java:262)
>>> >
>>> > I am giving the Mapper code below:
>>> >
>>> > import java.io.IOException;
>>> > import org.apache.hadoop.io.LongWritable;
>>> > import org.apache.hadoop.io.Text;
>>> > import org.apache.hadoop.mapred.MapReduceBase;
>>> > import org.apache.hadoop.mapred.Mapper;
>>> > import org.apache.hadoop.mapred.OutputCollector;
>>> > import org.apache.hadoop.mapred.Reporter;

Harsh J