A java programme to count the number of occurrences of each word in a sentence

NumberOfOccurences

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Scanner;


public class NumberOfOccurencesOfWordsInSentence {

	public static HashMap <Integer, String> stringMap = new HashMap<Integer, String>();
	public static HashMap <Integer, Integer> countMap = new HashMap<Integer, Integer>();
	
	public static void main(String[] args) throws IOException{

		Scanner in = new Scanner(System.in);
		System.out.println("Enter a sentence");
		String sentence = in.nextLine();
		ArrayList<String> words = separateWords(sentence);
		addWordsToMap(words);//arranges the words in a HashMap
		//printWordsInMap();
		returnCountOfWords();
	}
	
	//this function separates the words in the sentence and stores them in an ArrayList. 
	//word separating is done by finding blank spaces between 2 words
	public static ArrayList<String> separateWords(String sentence){
		ArrayList <String> words = new ArrayList<String>();
		int startIndex = 0;
		for (int i = 0; i < sentence.length(); i++) {
			if(sentence.charAt(i) == ' '){ //if blank space encountered
				words.add(sentence.substring(startIndex, i)); //finish this word and add it to the List
				startIndex = i+1;//start a new word
			}
		}
		words.add(sentence.substring(startIndex));//add the last word in the sentence
		return words;
	}
	
	public static void addWordsToMap(ArrayList<String> words){
		int key;
		for (int i = 0; i < words.size(); i++) {
			key = calculateAscii(words.get(i));
			stringMap.put(key, words.get(i));
			if(countMap.get(key) == null){
				countMap.put(key, 0);
			}
			countMap.put(key, countMap.get(key)+1);
		}
	}
	
	//this function returns the ASCII value of the word passed as argument
	public static int calculateAscii(String s){
		int value = 0;
		for (int i = 0; i < s.length(); i++) {
			value += (int)s.charAt(i);
		}
		return value;
	}
	
	//this function was made for debugging purposes
	/*public static void printWordsInMap(){
		Iterator iterator = stringMap.entrySet().iterator();
		while (iterator.hasNext()) {
			Map.Entry entry = (Map.Entry)iterator.next();
			System.out.println(entry.getKey() + " key has " + entry.getValue() + " value");
		}
	}*/
	
	//this function iterates through the HashMap and gives the output
	public static void returnCountOfWords(){
		Iterator iterator = countMap.entrySet().iterator();
		while(iterator.hasNext()){
			Map.Entry entry = (Map.Entry)iterator.next();
			System.out.println("The count of " + stringMap.get(entry.getKey()) + " is : " + entry.getValue());
		}
	}
}