WordCount.java

package test;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import java.util.TreeMap;

/**
 * Count number of word in file in ascending order
 * To run this program provide full path of file that has all words
 * update AVOID_WORD variable for words you dont want to include
 * @author yogeshupadhyay
 *
 */
public class WordCount {
    public static void main(String[] args) throws FileNotFoundException {
        // open the file
        Scanner console = new Scanner(System.in);
        System.out.print("What is the name of the text file? ");
        String fileName = console.nextLine();
        Scanner input = new Scanner(new File(fileName));
        final String[] AVOID_WORDS = new String[]{"is", "third"};
        // count occurrences
        Map<String, Integer> wordCounts = new HashMap<String, Integer>();
        while (input.hasNext()) {
            String next = input.next().toLowerCase();
            if(Arrays.asList(AVOID_WORDS).contains(next)) continue;
            if (!wordCounts.containsKey(next)) {
                wordCounts.put(next, 1);
            } else {
                wordCounts.put(next, wordCounts.get(next) + 1);
            }
        }

        // get cutoff and report frequencies
        System.out.println("Total words = " + wordCounts.size());
        int min = 1;
		Map<String, Integer> sortedMap = sortMapByValue(wordCounts);
		//System.out.println(sortedMap);
        		//wordCounts.entrySet().stream().sorted(Entry.comparingByValue()).collect(Collectors.toMap(Entry::getKey, Entry::getValue, (e1,e2) -> e1, TreeMap::new));
		for(Map.Entry<String, Integer> eachEntry: sortedMap.entrySet()) {
			System.out.println(eachEntry.getKey() + " " + eachEntry.getValue());
		}
    }
    
    public static TreeMap<String, Integer> sortMapByValue(Map<String, Integer> map){
		Comparator<String> comparator = new ValueComparator(new HashMap<>(map));
		//TreeMap is a map sorted by its keys. 
		//The comparator is used to sort the TreeMap by keys. 
		TreeMap<String, Integer> result = new TreeMap<String, Integer>(comparator);
		result.putAll(map);
		return result;
	}
    
}

//a comparator that compares Strings
class ValueComparator implements Comparator<String>{

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

	public ValueComparator(HashMap<String, Integer> map){
		this.map.putAll(map);
	}

	@Override
	public int compare(String s1, String s2) {
		if(map.get(s1) >= map.get(s2)){
			return -1;
		}else{
			return 1;
		}	
	}
}