Java vs Scala code length and style comparison

words-warp.scala

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

public class RunMe {

    public static void main(String[] args) {
        List<String> sentences = new ArrayList<String>();
        sentences.add("This is the first sentence.");
        sentences.add("This is the second sentence.");
        sentences.add("This is the third sentence.");
         
        Map<String, List<String>> wordMap = makeWordMap(sentences);
        Iterator<Map.Entry<String, List<String>>> iter = wordMap.entrySet().iterator();
        StringBuffer sb = new StringBuffer();
        while (iter.hasNext()) {
            Map.Entry<String, List<String>> entry = iter.next();
            sb.append(entry.getKey())
                .append(" -> ")
                .append(entry.getValue().size())
                .append('\n');
        }
        System.out.println(sb.toString());
    }


    static String[] words(String sentence) {
        return sentence.split(" ");
    }

    static Map<String, List<String>> makeWordMap(List<String> sentences) {
     
        Map<String, List<String>> result = new HashMap<>();
     
        for (String sentence: sentences) {
            for (String word: words(sentence)) {
                List<String> sentencesForWord = result.get(word);
                if (sentencesForWord == null) {
                    sentencesForWord = new ArrayList<String>();
                    result.put(word, sentencesForWord);
                }
                sentencesForWord.add(sentence);
            }
        }
        return result;
    }
}

words-wrap.scala

val sentences = List("This is the first sentence.", "This is the second sentence.", "This is the third sentence.")
val wordsWarp = sentences.foldLeft(Map[String, List[String]]()){
  case (m, s) => s.split(" ").foldLeft(m){
    case (m2, word) => m2 + (word -> (s :: (m2.getOrElse(word, Nil))))}}
wordsWarp.foreach{case (k,v) => println(s"$k -> ${v.size}")}

// removed intermediate val
List("This is the first sentence.", 
    "This is the second sentence.", 
    "This is the third sentence.").foldLeft(Map[String, List[String]]()){
        case (m, s) => s.split(" ").foldLeft(m){
            case (m2, word) => m2 + (word -> (s :: (m2.getOrElse(word, Nil))))}}.foreach{
                case (k,v) => println(s"$k -> ${v.size}")}