Reference: Functional Thinking Chapter 2

NameCleaner.java

// Java版本
import java.util.List;
import java.util.ArrayList;
public class NameCleaner {
     public static String cleanNames(List<String> listOfNames) {
         StringBuilder result = new StringBuilder();
         for(int i = 0; i < listOfNames.size(); i++) {
             if(listOfNames.get(i).length() > 1) {
                 result.append(capitalizeString(listOfNames.get(i))).append(",");
             }
         }
         return result.substring(0, result.length() - 1).toString();
     }
     public static String capitalizeString(String s) {
         return s.substring(0, 1).toUpperCase() + s.substring(1, s.length());
     }
     public static void main(String []args){
        List<String> names = new ArrayList<String>() {{
            add("jack");
            add("k");
            add("john");
            add("joe");
        }};
        System.out.println("The original names: " + names);
        System.out.println("The cleaned names: " + cleanNames(names));
     }
}

NameCleaner.scala

// Scala版本
object NameCleaner {
    def cleanNames(listOfNames : List[String]) : String = {
        listOfNames
            .filter(_.length > 1)
            .map(_.capitalize)
            .reduce(_ + "," + _)
    }
    def main(args : Array[String]) {
        val names = List("jack", "k", "john", "joe");
        println("The original names: " + names);
        println("The cleaned names: " + cleanNames(names));
    }
}