Listing 2. MyMapReduce.java 

import java.util.*;

public class MyMapReduce
{
	List buckets = new ArrayList();
	List intermediateresults = new ArrayList();
	List values = new ArrayList();

	public void init()
	{
		for(int i = 1; i<=30; i++)
		{
			values.add("ABC" + new Integer(i).toString());
		}



		System.out.println("**STEP 1 START**-> Running Conversion into Buckets**");
		System.out.println();
		List b = step1ConvertIntoBuckets(values,5);
        System.out.println("************STEP 1 COMPLETE*************");
        System.out.println();
        System.out.println();

   System.out.println("**STEP 2 START**->Running **Map Function** concurrently for all        Buckets");
		System.out.println();
		List res = step2RunMapFunctionForAllBuckets(b);
		System.out.println("************STEP 2 COMPLETE*************");

        System.out.println();
        System.out.println();
		System.out.println("**STEP 3 START**->Running **Reduce Function** for collating Intermediate Results and Printing Results");
		System.out.println();
		step3RunReduceFunctionForAllBuckets(res);
		System.out.println("************STEP 3 COMPLETE*************");

	}
	public List step1ConvertIntoBuckets(List list,int numberofbuckets)
	{
		int n = list.size();
		int m = n / numberofbuckets;
		int rem = n% numberofbuckets;

		int count = 0;
		System.out.println("BUCKETS");
		for(int j =1; j<= numberofbuckets; j++)
		{
			List temp = new ArrayList();
			for(int i=1; i<= m; i++)
			{

				temp.add((String)values.get(count));
				count++;


			}
			buckets.add(temp);
			temp = new ArrayList();
		}
		if(rem != 0)
		{
			List temp = new ArrayList();
			for(int i =1; i<=rem;i++)
			{

				temp.add((String)values.get(count));
				count++;
			}
			buckets.add(temp);
		}
        System.out.println();
		System.out.println(buckets);
		System.out.println();
		return buckets;

	}

	public List step2RunMapFunctionForAllBuckets(List list)
	{
		for(int i=0; i< list.size(); i++)
		{
			List elementList = (ArrayList)list.get(i);
			new StartThread(elementList).start();
		}

        try
        {
		Thread.currentThread().sleep(1000);
		}catch(Exception e)
		{
		}
		return intermediateresults;
	}

	public void step3RunReduceFunctionForAllBuckets(List list)
	{
		int sum =0;
		for(int i=0; i< list.size(); i++)
		{
			//you can do some processing here, like finding max of all results etc
			int t = Integer.parseInt((String)list.get(i));
			sum += t;
		}


		System.out.println();
		System.out.println("Total Count is "+ sum);
		System.out.println();

	}

		class StartThread extends Thread
		{
			private List tempList = new ArrayList();
			public StartThread(List list)
			{
				tempList = list;
			}
			public void run()
			{

				for(int i=0; i< tempList.size();i++)
				{
					String str = (String)tempList.get(i);

					synchronized(this)
                     {
						intermediateresults.add(new Integer(str.length()).toString());
					 }


				}
			}

		}

}