Hadoop Distributed Cache throws IOException

Question

using hadoop 0.20.2 and trying to read a serialized map via distributed cache

facing a compilation error localFiles = DistributedCache.getLocalCacheFiles(job); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Unhandled exception type IOException

DRIVER Class snippet (/scratch/word_id.ser is a serialized file stored in local system)

    Job job = new Job(conf, "xml-read");
    DistributedCache.addCacheFile(new URI("/scratch/word_id.ser"),job);

MAPPER Class snippet

    public class MyParserMapper1 {

    public static class Map extends MapReduceBase implements Mapper<LongWritable, Text, IntWritable, Text> {

    private FileSystem fs;
    private Path[] localFiles;
    HashMap  hash_temp;
    private ObjectInputStream oisc;

    @Override
    public void configure(JobConf job)   {

     localFiles = DistributedCache.getLocalCacheFiles(job);

    }

Answer 1

Your IDE probably has some auto-fix rules for things like this, but anyway, you need to wrap the statement in a try / catch block:

@Override
public void configure(JobConf job)   {
  try {
    localFiles = DistributedCache.getLocalCacheFiles(job);
  } catch (IOException ioe) {
    throw new RuntimException(ioe);
  }
}

If you can handle the exception all the better (ie if you can still run your mapper without this file), but otherwise just wrap in an unchecked exception like RuntimeException