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MapReduce >> mail # user >> Secondary Sort example error


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Re: Secondary Sort example error
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;
>> > import org.apache.log4j.Logger;
>> > import com.pom.Name;
>> >
>> > public class StubMapper extends MapReduceBase implements
>> >     Mapper<LongWritable, Text, Name, Text> {
>> >
>> >   private static Logger logger >> >     Logger.getLogger(StubMapper.class.getName());
>> >
>>
Harsh J