명령형 프로그래밍

PersonList.java

import java.util.ArrayList;
import java.util.List;

public class PersonList {
    
    public String cleanNames(List<String> listOfNames) {
        StringBuilder builder = new StringBuilder();
        
        for(int i = 0; i < listOfNames.size(); i++) {
            if(listOfNames.get(i).length() > 1) {
                builder.append(capitalizeString(listOfNames.get(i))).append(",");
            }
        }
        
        return builder.substring(0, builder.length() - 1).toString();
    }

    private String capitalizeString(String string) {
        return string.substring(0, 1).toUpperCase() + string.substring(1, string.length());
    }
    
    public static void main(String[] args) {
        ArrayList<String> list = new ArrayList<>();
        list.add("james");
        list.add("s");
        list.add("kevin");
        list.add("paul");
        
        String result = new PersonList().cleanNames(list);
        System.out.println(result);
    }
}