Java count occurrence of a word

The given code reads the text file and count the occurrence of each word.

import java.io.*;
import java.util.*;

public class CountWordOccurrence {
        public static void main(String[] args){
try{
       BufferedReader br=new BufferedReader(new FileReader("c:/data.txt"));
       String str="";
        String st;
        while((st=br.readLine())!=null){
            str+=st+" ";
        }
        HashMap<String, Integer> map = new HashMap<String, Integer>();


            str = str.toLowerCase(); 
                int count = -1;
                for (int i = 0; i < str.length(); i++) { 
                   if ((!Character.isLetter(str.charAt(i))) || (i + 1 == str.length())) { 
                            if (i - count > 1) { 
                            if (Character.isLetter(str.charAt(i))) 
                                i++;
                            String word = str.substring(count + 1, i);
                            if (map.containsKey(word)) { 
                            map.put(word, map.get(word) + 1);
                            }
                            else { 
                            map.put(word, 1);
                            } 
                        } 
                        count = i;
                    } 
                } 
        ArrayList<Integer> list = new ArrayList<Integer>();
        list.addAll(map.values());
        Collections.sort(list, Collections.reverseOrder());
        int last = -1;
        for (Integer i : list) { 
            if (last == i) 
                continue;
            last = i;
            for (String s : map.keySet()) { 
                if (map.get(s) == i) 
                    System.out.println(s + ":" + i);
            } 
        }
}
catch(Exception e){
System.out.println(e);
}
    } 
}