ClassCastException with LineRecordReader (hadoop release version 0.21.0)

[Claus Stadler]

Hi,

I guess I am not the first one to see the following exception when 
trying to initialize a LineRecordReader. However, so far I could't 
figure out a workaround for this problem.

I saw that this problem was fixed in the svn, but when I checked out one 
of the 0.23.0 versions (I can't remember which) I couldn't get the 
servers started. (Not sure if that was due to the revision, or me 
messing up the setup).

So maybe someone can point me to a known workaround for this problem or 
at least hinting a revision that other people got to work?

Kind regards,
Claus


ps: Essentially I am just doing this:

    public static class MyInputFormat extends
            FileInputFormat<Text, ByteWritable>
    {
        @Override
        public RecordReader<Text, ByteWritable> 
createRecordReader(InputSplit inputSplit, TaskAttemptContext 
taskAttemptContext)
            throws IOException, InterruptedException
        {
            MyRecordReader result = new MyRecordReader();
            result.initialize(inputSplit, taskAttemptContext);
            return result;
        }
    }

    public static class MyRecordReader extends
            RecordReader<Text, ByteWritable>
    {
        LineRecordReader myReader = new LineRecordReader();
        ...
        @Override
        public void initialize(InputSplit inputSplit, 
TaskAttemptContext taskAttemptContext)
            throws IOException, InterruptedException
        {
            myReader.initialize(inputSplit, taskAttemptContext); // 
EXCEPTION THROWN HERE
        }
         ...
    }

   job.setInputFormatClass(MyInputFormat.class);


The exception is:

java.lang.Exception: java.lang.ClassCastException: 
org.apache.hadoop.mapreduce.task.TaskAttemptContextImpl cannot be cast 
to org.apache.hadoop.mapreduce.MapContext
    at 
org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:371) 
~[hadoop-mapred-0.21.0.jar:na]
java.lang.ClassCastException: 
org.apache.hadoop.mapreduce.task.TaskAttemptContextImpl cannot be cast 
to org.apache.hadoop.mapreduce.MapContext
    at 
org.apache.hadoop.mapreduce.lib.input.LineRecordReader.initialize(LineRecordReader.java:75) 
~[hadoop-mapred-0.21.0.jar:na]
(rest of the output is within my code)