[jira] Created: (HADOOP-4452) Hadoop streaming doc should not use IdentityMapper as an example

["Marco Nicosia (JIRA)" <ji...@apache.org>]

Hadoop streaming doc should not use IdentityMapper as an example
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                 Key: HADOOP-4452
                 URL: https://issues.apache.org/jira/browse/HADOOP-4452
             Project: Hadoop Core
          Issue Type: Bug
    Affects Versions: 0.18.1
            Reporter: Marco Nicosia
            Priority: Minor


>From the URL http://hadoop.apache.org/core/docs/current/streaming.html

This example doesn't work:
{quote}
You can supply a Java class as the mapper and/or the reducer. The above example is equivalent to:

$HADOOP_HOME/bin/hadoop  jar $HADOOP_HOME/hadoop-streaming.jar \
    -input myInputDirs \
    -output myOutputDir \
    -mapper org.apache.hadoop.mapred.lib.IdentityMapper \
    -reducer /bin/wc
{quote}

This will produce the following exception:
{quote}
java.io.IOException: Type mismatch in key from map: expected org.apache.hadoop.io.Text, recieved org.apache.hadoop.io.LongWritable
{quote}


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