package jp.co.jid.xxx; import java.util.HashSet; public class Respondents3 { private static final String[] RESPONDENTS_ARRAY = {""}; private static final int COUNT = 6; public static void main(String[] args) { HashSet<String> set = new HashSet<String>(); while (set.size() < COUNT) { set.add(RESPONDENTS_ARRAY[(int)(Math.random() * (RESPONDENTS_ARRAY.length))]); } for (String name : set) { System.out.println(name); } } }