I have a simple hadoop application, which get one CSV file, then split the entry by ",", then count the first items.

The following is my code.

package com.bluedolphin;

import java.io.IOException;
import java.util.Iterator;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
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.util.Tool;
import org.apache.hadoop.util.ToolRunner;

public class MyJob extends Configured implements Tool {
    private final static LongWritable one = new LongWritable(1);


    public static class MapClass extends Mapper<Object, Text, Text, LongWritable> {
        private Text word = new Text();
        public void map(Object key, 
                    Text value, 
                    OutputCollector<Text, LongWritable> output,
                    Reporter reporter) throws IOException, InterruptedException {
            String[] citation = value.toString().split(",");
            word.set(citation[0]);
            output.collect(word, one);
        }
    }

    public static class Reduce extends Reducer<Text, LongWritable, Text, LongWritable> {
        public void reduce(
                Text key, 
                Iterator<LongWritable> values, 
                OutputCollector<Text, LongWritable> output,
                Reporter reporter) throws IOException, InterruptedException {
            int sum = 0;

            while (values.has
java hadoop
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