hi Maybe you can read this http://www.vimeo.com/2085477 first
Dear friends, I am new at Hadoop and at MapReduce techniques. I've developed my first map-reduce application using hadoop but I can't manage to make it work. I get the following error at the very beginning of the execution: java.lang.NullPointerException at org.apache.hadoop.io.serializer.SerializationFactory.getSerializer(SerializationFactory.java:73) at org.apache.hadoop.mapred.MapTask$MapOutputBuffer.<init>(MapTask.java:504) at org.apache.hadoop.mapred.MapTask.run(MapTask.java:295) at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:138) 16-ene-2009 18:29:30 es.vocali.intro.tools.memo.MemoAnnotationMerging main GRAVE: Se ha producido un error java.io.IOException: Job failed! at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:1217) at es.vocali.intro.tools.memo.MemoAnnotationMerging.main(MemoAnnotationMerging.java:160) java.io.IOException: Job failed! at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:1217) at es.vocali.intro.tools.memo.MemoAnnotationMerging.main(MemoAnnotationMerging.java:160) Sorry if I don't give you more information but I don't know where to start to find the error. My app is quite simple. It just gets some rows from a postgresql database and try to see which ones can be deleted.
-- Yi-Kai Tsai (cuma) <yi...@yahoo-inc.com>, Asia Regional Search Engineering.