title: Hadoop job just ends
body: <p>I'm having a rather strange problem with Hadoop. </p>
  
  <p>I wrote a MR job that ends just like that, without executing map or reduce code. It produces the output folder, but that folder is empty. I see no reason for such a behavior.</p>
  
  <p>I'm even trying out this with default Mapper and Reducer, just to find the problem, but I get no exception, no error, the job just finishes and produces an empty folder. Here's the simplest driver:</p>
  
  <pre><code>    Configuration conf = new Configuration();
  
      //DistributedCache.addCacheFile(new URI(firstPivotsInput), conf);
  
      Job pivotSelection = new Job(conf);
      pivotSelection.setJarByClass(Driver.class);
      pivotSelection.setJobName("Silhoutte");
  
      pivotSelection.setMapperClass(Mapper.class);
      pivotSelection.setReducerClass(Reducer.class);
  
      pivotSelection.setMapOutputKeyClass(IntWritable.class);
      pivotSelection.setMapOutputValueClass(Text.class);
  
      pivotSelection.setOutputKeyClass(IntWritable.class);
      pivotSelection.setOutputValueClass(Text.class);
  
      FileInputFormat.addInputPath(pivotSelection, new Path("/home/pera/WORK/DECOMPRESSION_RESULT.csv"));
      FileOutputFormat.setOutputPath(pivotSelection, new Path("/home/pera/WORK/output"));
  
      pivotSelection.setNumReduceTasks(1);
  
      pivotSelection.waitForCompletion(true);
  </code></pre>
  
  <p>What could be the problem in such a simple example?</p>