[JAVA] A program that counts the number of words in a List

For some reason, I have constant access to the "Java word counting program" in my program every day. So, I posted the code posted on that blog I wrote it more than 10 years ago, but when I look at it now, I'm embarrassed that I don't use the generic type for List, and there are various immature parts.


import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

public class WordCounterTable {
    private Map counterTable;
    public WordCounterTable(){
        this.counterTable = new HashMap();    

    public void count(List list){
        for(Iterator ite = list.iterator();ite.hasNext();){
            Object target = ite.next();
            if(this.counterTable.get(target) == null){
                this.counterTable.put(target,new Integer(1));    
                new Integer(
    public String printTableValue(){
        StringBuffer buf = new StringBuffer();
        for(Iterator ite = this.counterTable.keySet().iterator();ite.hasNext();){
            Object key = ite.next();
            buf.append("word:"+key+" count:"+this.counterTable.get(key)+"\n");
        return buf.toString();

So, I can't keep posting such an embarrassing program on my blog forever, so I rewrote it using the Stream function of Java8.


package test;

import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import java.util.function.Function;

public class WordCount {

	public static void main(String args[]){
		List<String> list = Arrays.asList("triple","evergreen","puisan","triple","puisan");
		Map<String,Integer> map = list.stream().collect(
						//Set the List element as it is in the Map key
						//Replace the List element with 1 for the Map value so that it counts
//{triple=2, puisan=2, evergreen=1}Is output to the console

The Stream function is convenient, isn't it? Compared to the previous light program, the logic is cleaner and it looks beautiful.

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