Seems like a bug in your code, can you share the source here? +Vinod
On Tue, Jan 29, 2013 at 4:00 AM, Vikas Jadhav <vikascjadha...@gmail.com>wrote: > I am using Hadoop 1.0.3 > > I am getting following Error > > > 13/01/29 06:55:19 INFO mapred.JobClient: Task Id : > attempt_201301290120_0006_r_000000_0, Status : FAILED > java.lang.NullPointerException > at MyJoin$TaggedWritable.readFields(MyJoin.java:101) > at > org.apache.hadoop.io.serializer.WritableSerialization$WritableDeserializer.deserialize(WritableSerialization.java:67) > at > org.apache.hadoop.io.serializer.WritableSerialization$WritableDeserializer.deserialize(WritableSerialization.java:40) > at > org.apache.hadoop.mapred.Task$ValuesIterator.readNextValue(Task.java:1271) > at > org.apache.hadoop.mapred.Task$ValuesIterator.next(Task.java:1211) > at > org.apache.hadoop.mapred.ReduceTask$ReduceValuesIterator.moveToNext(ReduceTask.java:249) > at > org.apache.hadoop.mapred.ReduceTask$ReduceValuesIterator.next(ReduceTask.java:245) > at > org.apache.hadoop.contrib.utils.join.DataJoinReducerBase.regroup(DataJoinReducerBase.java:106) > at > org.apache.hadoop.contrib.utils.join.DataJoinReducerBase.reduce(DataJoinReducerBase.java:129) > at > org.apache.hadoop.mapred.ReduceTask.runOldReducer(ReduceTask.java:519) > at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:420) > at org.apache.hadoop.mapred.Child$4.run(Child.java:255) > 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:1121) > at org.apache.hadoop.mapred.Child.main(Child.java:249) > > > > > It is poiting to String dataClz = in.readUTF(); this line in readFields > > > * > > public > * > > *void* readFields( DataInput in) *throws* IOException > > { > > *this*.tag.readFields( in); > > //String dataClz = in.readUTF(); > > String dataClz = in.readUTF(); ----> error log show this line is culprit > > *try* > * * > > { > > //try - catch is needed because the " error: unreported exception > > //ClassNotFoundException; must be caught or declared to be thrown" > > //is "raised" from compiler > > *if*( *this*.data == *null* || !*this*.data.getClass().getName().equals( > dataClz)) > > { > > //this line of code "raises" the compile error mentioned above > > *this*.data = (Writable) ReflectionUtils.*newInstance*( Class.*forName*( > dataClz), *null*); > > } > > *this*.data.readFields( in); > > } > > *catch*( ClassNotFoundException cnfe) > > { > > System.*out*.println( "Problem in TaggedWritable class, method > readFields."); > > } > > }//end readFields > > > -- > * > * > * > > Thanx and Regards* > * Vikas Jadhav* > -- +Vinod Hortonworks Inc. http://hortonworks.com/