hadoop file system

I am trying torun the code below in hdfs but it couldn't work well it is LetterCount similar to wordcount example

import java.io.IOException;

import java.util.*;

import org.apache.hadoop.conf.*;

import org.apache.hadoop.fs.Path;

import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;

import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;

import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;

import org.apache.hadoop.io.IntWritable;

import org.apache.hadoop.io.LongWritable;

import org.apache.hadoop.io.Text;

import org.apache.hadoop.mapreduce.Job;

import org.apache.hadoop.mapreduce.Mapper;

import org.apache.hadoop.mapreduce.Reducer;

public class LetterCount {

//create class for count letter frequency in separate elements (for tasks)

public static class LettersMapper

extends Mapper {

//base for separate is number of line (we read text line by line), line

//output: characters and frequence

public void map(LongWritable key, Text value, Context context)

throws IOException, InterruptedException {

String line = value.toString();

//go throw character of line which was converted to lower case

for (char s : line.toLowerCase().toCharArray()) {

//add 1 for frequence

context.write(s, new IntWritable(1));

}

}

}

//class for join all the tasks

public static class LetterReducer

extends Reducer {

//we join all values for same key

public void reduce(Character key, Iterable values, Context context)

throws IOException, InterruptedException {

int count = 0;

for (IntWritable value : values) {

count += value.get();

}

context.write(key, new IntWritable(count));

}

}

//main program

public static void main(String[] args)

throws Exception {

//check for amount aruments

if (args.length != 2) {

System.err.println("Usage: LetterCount

");

System.exit(-1);

}

//set parameters of the job

Configuration conf;

conf=new Configuration();

Job job = new Job(conf, "letterCount");

job.setJarByClass(LetterCount.class);

job.setJobName("Letter Count without case sensetive");

job.setNumReduceTasks(2);

FileInputFormat.addInputPath(job, new Path(args[0]));

FileOutputFormat.setOutputPath(job, new Path(args[1]));

job.setMapperClass(LettersMapper.class);

job.setReducerClass(LetterReducer.class);

job.setOutputKeyClass(Character.class);

job.setOutputValueClass(IntWritable.class);

System.exit(job.waitForCompletion(true) ? 0 : 1);

}

}