title: How to resolve java.lang.RuntimeException: PipeMapRed.waitOutputThreads(): subprocess failed with code 2?
body: <p>I am trying to execute NLTK in Hadoop environment. Following is the command which i used for execution.</p>
  
  <pre><code>bin/hadoop jar $HADOOP_HOME/contrib/streaming/hadoop-streaming-1.0.4.jar -input /user/nltk/input/ -output /user/nltk/output1/ -file /home/hduser/softwares/NLTK/unsupervised_sentiment-master.zip -mapper /home/hduser/softwares/NLTK/unsupervised_sentiment-master/sentiment.py
  </code></pre>
  
  <p>unsupervised_sentiment-master.zip --- contains all the dependent files required for sentiment.py</p>
  
  <p>I am getting </p>
  
  <pre><code>java.lang.RuntimeException: PipeMapRed.waitOutputThreads(): subprocess failed with code 2
      at org.apache.hadoop.streaming.PipeMapRed.waitOutputThreads(PipeMapRed.java:362)
      at org.apache.hadoop.streaming.PipeMapRed.mapRedFinished(PipeMapRed.java:576)
      at org.apache.hadoop.streaming.PipeMapper.close(PipeMapper.java:135)
      at org.apache.hadoop.mapred.MapRunner.run(MapRunner.java:57)
      at org.apache.hadoop.streaming.PipeMapRunner.run(PipeMapRunner.java:36)
      at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:436)
      at org.apache.hadoop.mapred.MapTask.run(MapTask.java:372)
      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:415)
      at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
      at org.apache.hadoop.mapred.Child.main(Child.java:249)
  </code></pre>
  
  <p>Any help would be greatly appreciated!!!</p>