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From: Prakrati Agrawal <Prakrati.Agrawal@mu-sigma.com>
To: "user@hbase.apache.org" <user@hbase.apache.org>
Date: Tue, 26 Jun 2012 02:29:18 -0500
Subject: Getting Null Pointer Exception when using Map Reduce for retrieval
Thread-Topic: Getting Null Pointer Exception when using Map Reduce for
 retrieval
Thread-Index: Ac1TbWWqD5Wvx62lRRaXGzcWtbkzxA==
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Dear all

I created a database in HBase. First I was retrieving it using Java APIs bu=
t it was taking a lot of time(43 seconds) to retrieve it. I thought of writ=
ing Map Reduce code to retrieve it to make it faster. But I am getting Null=
 Pointer Exception in my code. Following is the excerpt from my code:

TableMapReduceUtil.initTableMapperJob(
                                                  tableName,        // inpu=
t HBase table name
                                                  scanRows,             // =
Scan instance to control CF and attribute selection
                                                  MyMapper.class,   // mapp=
er
                                                  null,             // mapp=
er output key
                                                  null,             // mapp=
er output value
                                                  job);
job.setOutputFormatClass(NullOutputFormat.class);   // because we aren't em=
itting anything from mapper

boolean b =3D job.waitForCompletion(true);
if (!b) {
              throw new IOException("error with job!");
}


The error I get is as follows:
Exception in thread "main" java.lang.NullPointerException
            at org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil.initTab=
leMapperJob(TableMapReduceUtil.java:100)
            at org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil.initTab=
leMapperJob(TableMapReduceUtil.java:75)

Please help me


Thanks and Regards
Prakrati Agrawal | Developer - Big Data(I&D)| 9731648376 | www.mu-sigma.com


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