Thanks for replying.=A0 . I believe writable and writ= ablecomparable handle the serialization..=A0=A0I found the required class

=A0

public class Name implements WritableComparable<N= ame>{
=A0
=A0private=A0String fName;
=A0private=A0String lName;

= =A0 static {=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 // register this comparator=A0=A0=A0=A0=A0=A0 WritableComparator.define(Name.class, new NameSorterCo= mparator());
=A0=A0=A0=A0 }
=A0
=A0
=A0public Name()
=A0{
=A0=A0
=A0}
=A0
=A0public Name(String first, String last)<= br>=A0{
=A0=A0set(first, last);
=A0}
=A0
=A0 public void set(St= ring first, String last) {
=A0=A0 this.fName =3D first;
=A0 this.lNa= me =3D last;
=A0 }

=A0public String getfName() {
=A0=A0return fName;
=A0}
=A0public v= oid setfName(String fName) {
=A0=A0this.fName =3D fName;
=A0}
=A0p= ublic String getlName() {
=A0=A0return lName;
=A0}
=A0public void = setlName(String lName) {
=A0=A0this.lName =3D lName;
=A0}

=A0public String toString()=A0{
=A0=A0return this.getfName()+" "+this.getlName();=A0=A0=
=A0}
=A0
=A0@Override
=A0public void write(DataOutput out) thr= ows IOException {
=A0=A0// TODO Auto-generated method stub
=A0=A0out.writeUTF(fName);
=A0=A0out.writeUTF(lName);
=A0}

= =A0public boolean equals(Name=A0 o) {
=A0=A0Name other =3D o;

= =A0=A0if(this.fName.toString().equalsIgnoreCase(other.fName.toString()))=A0=A0{
=A0=A0=A0if(this.lName.toString().equalsIgnoreCase(other.lName.= toString()))
=A0=A0=A0{
=A0=A0=A0=A0return true;
=A0=A0=A0}
=A0=A0}
=A0=A0re= turn false;
=A0}

=A0@Override
=A0public void readFields(Dat= aInput in) throws IOException {
=A0=A0// TODO Auto-generated method stub=
=A0=A0this.fName =3D in.readUTF();
=A0=A0this.lName =3D in.readUTF();
=A0}

=A0@Override
=A0pub= lic int hashCode() {
=A0=A0return fName.hashCode() * 514 + lName.hashCod= e();
=A0}

=A0@Override
=A0public int compareTo(Name tp) {=A0=A0int cmp =3D fName.compareTo(tp.fName);
=A0=A0if (cmp !=3D 0) {
=A0=A0=A0return cmp;
=A0=A0}
=A0=A0return = lName.compareTo(tp.lName);
=A0}

}=A0

On Fri, Feb 8, 2013 at 12:1= 6 AM, Harsh J <harsh@cloudera.com> wrote:

Thanks, I managed to correlate proper line n= umbers.

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
<ravichandran777@gmail.com<= /a>> 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/BUI= LD/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 <harsh@cloudera.com> 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
>> <ravichandran777@g= mail.com> 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 reaso= n. 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 libra= ry is
>> > available
>> > 13/02/07 12:23:42 INFO snappy.LoadSnappy: Snappy native libra= ry loaded
>> > 13/02/07 12:23:42 INFO mapred.FileInputFormat: Total input pa= ths 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: =A0map 0% reduce 0%<= br> >> > 13/02/07 12:23:56 INFO mapred.JobClient: Task Id :
>> > attempt_201301301056_0014_m_000000_0, Status : FAILED
>> > java.lang.NullPointerException
>> > =A0at
>> >
>> > org.apache.hadoop.mapred.MapTask$MapOutputBuffer.<init>= (MapTask.java:814)
>> > =A0at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.j= ava:385)
>> > =A0at org.apache.hadoop.mapred.MapTask.run(MapTask.java:327)<= br> >> > =A0at org.apache.hadoop.mapred.Child$4.run(Child.java:268) >> > =A0at java.security.AccessController.doPrivileged(Native Meth= od)
>> > =A0at javax.security.auth.Subject.doAs(Subject.java:396)
>> > =A0at
>> >
>> > org.apache.hadoop.security.UserGroupInformation.doAs(UserGrou= pInformation.java:1332)
>> > =A0at org.apache.hadoop.mapred.Child.main(Child.java:262)
>> > 13/02/07 12:23:57 INFO mapred.JobClient: Task Id :
>> > attempt_201301301056_0014_m_000001_0, Status : FAILED
>> > java.lang.NullPointerException
>> > =A0at
>> >
>> > org.apache.hadoop.mapred.MapTask$MapOutputBuffer.<init>= (MapTask.java:814)
>> > =A0at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.j= ava:385)
>> > =A0at org.apache.hadoop.mapred.MapTask.run(MapTask.java:327)<= br> >> > =A0at org.apache.hadoop.mapred.Child$4.run(Child.java:268) >> > =A0at java.security.AccessController.doPrivileged(Native Meth= od)
>> > =A0at javax.security.auth.Subject.doAs(Subject.java:396)
>> > =A0at
>> >
>> > org.apache.hadoop.security.UserGroupInformation.doAs(UserGrou= pInformation.java:1332)
>> > =A0at 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
>> > =A0 =A0 Mapper<LongWritable, Text, Name, Text> {
>> >
>> > =A0 private static Logger logger =3D
>> > =A0 =A0 Logger.getLogger(StubMapper.class.getName());
>> >
>> > =A0StringBuffer readLine =3D new StringBuffer();
>> > =A0 private final Name name =3D new Name();
>> > =A0 @Override
>> > =A0 public void map(LongWritable key, Text value,
>> > =A0 =A0 =A0 OutputCollector<Name, Text> output, Reporte= r reporter)
>> > =A0 =A0 =A0 throws IOException {
>> > =A0 =A0 String line =3D value.toString();
>> > =A0 =A0 String[] packer =3D null;
>> >
>> > =A0 =A0 packer =3D line.split(" ");
>> >
>> > =A0 =A0 // create the object
>> > =A0if(packer.length>2)
>> > =A0{
>> > =A0 // take everything except last name
>> > =A0 for (int i =3D 0; i < packer.length-1; i++) {
>> > =A0 =A0readLine.append(packer[i]+" ");
>> > =A0 }
>> >
>> > =A0 name.setfName(readLine.toString());
>> > =A0 name.setlName(packer[packer.length-1]);
>> >
>> > =A0 //clear the variable
>> > =A0 readLine.delete(0, readLine.length());
>> > =A0}
>> > =A0else if(packer.length>0)
>> > =A0{
>> > =A0 name.setfName(packer[0]);
>> > =A0 =A0 =A0name.setlName(packer[1]);
>> > =A0 =A0}
>> >
>> > =A0output.collect(name, new Text(name.getlName()));
>> >
>> > =A0 }
>> > }
>> >
>> > I am not able to figure out the possible cause..
>> >
>> > --
>> > Thanks & Regards
>> > Ravi
>>
>>
>>
>> --
>> Harsh J
>
>
>
>
> --
> Thanks & Regards
> Ravi

--
Harsh J

--
Thanks & RegardsRavi