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From Minh Duc Nguyen <mdngu...@gmail.com>
Subject Re: Getting Null Pointer Exception when using Map Reduce for retrieval
Date Tue, 26 Jun 2012 12:51:46 GMT
Prakrati,

   Assuming you're using HBase version 0.90.3:

http://grepcode.com/file/repo1.maven.org/maven2/org.apache.hbase/hbase/0.90.3/org/apache/hadoop/hbase/mapreduce/TableMapReduceUtil.java

It would appear that your job variable is null.  For future reference,
it helps a lot if you can provide the version of HBase you're using.

   ~ Minh

On Tue, Jun 26, 2012 at 3:29 AM, Prakrati Agrawal
<Prakrati.Agrawal@mu-sigma.com> wrote:
> Dear all
>
> I created a database in HBase. First I was retrieving it using Java APIs but it was taking
a lot of time(43 seconds) to retrieve it. I thought of writing 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,
       // input HBase table name
>                                                  scanRows,  
          // Scan instance to control CF and attribute selection
>                                                  MyMapper.class,
  // mapper
>                                                  null,    
        // mapper output key
>                                                  null,    
        // mapper output value
>                                                  job);
> job.setOutputFormatClass(NullOutputFormat.class);   // because we aren't emitting anything
from mapper
>
> boolean b = 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.initTableMapperJob(TableMapReduceUtil.java:100)
>            at org.apache.hadoop.hbase.mapreduce.TableMapReduceUtil.initTableMapperJob(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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