Java Program To Print Consecutive characters and the number of times it occurs in ascending order of number of occurrences

Sample 
-----------
 input : “I saw a cd player and a modem in ccd”

     output :  de-->  1 
                  cd --> 2 
                  I saw a player and a mom in c

ContiAlpha.java

package com.test;

import java.io.IOException;

import java.util.ArrayList;

import java.util.Collections;

import java.util.HashMap;

import java.util.Set;

public class ContiAlpha

{

    public static void main(String[] args) throws IOException

    {

      try

      {

        HashMap<String, Integer> map= new HashMap<String, Integer>();

        String s1="I saw a cd  ghplayer and a modem degh in ccd";

        s1=s1.toLowerCase();

        for(int i=0;i<(s1.length()-1);i++)

        {

            if(s1.charAt(i+1)-s1.charAt(i)==1)

            {

                String word=s1.charAt(i)+""+s1.charAt(i+1);

       

                if(map.containsKey(word))

                {

                    int value=map.get(word);

                    map.put(word,++value);

                } 

                    else

                    {

                        map.put(word, 1);

                    }

            }               

        }  

        ArrayList<ContiSortByValue> list=new ArrayList<ContiSortByValue>();

             Set<String> keySet=map.keySet();

             String s2=s1;

             for(String k : keySet)

             {

                  s2=s2.replace(k, "");

                 int value=map.get(k);

                 list.add(new ContiSortByValue(k, value));             

             }

             System.out.println(s2);

             Collections.sort(list);

             for(ContiSortByValue sort : list)

             {

                 System.out.println(sort);

             }

      }   

      catch (Exception e)

      {

            e.printStackTrace();

      }           

    }

}

ContiSortByValue.java 

package com.test;

public class ContiSortByValue implements Comparable<ContiSortByValue>

{

    private String key;

    private Integer value;

    public ContiSortByValue()

    {

        // TODO Auto-generated constructor stub

    }

       public ContiSortByValue(String key, Integer value)

      {

        super();

        this.key = key;

        this.value = value;

      }

    @Override

    public int compareTo(ContiSortByValue obj)

   {    

        return this.value - obj.value;

    }

    @Override

    public String toString()

    {

        return key + "-->" + value;

    }

}

output:

de-->1
cd-->2
i saw a  player and a mom in c