Java 比较集合中的元素

import java.util.Collections; 
import java.util.Set;
import java.util.TreeSet;

class Main {
   public static void main(String[] args) {
      String[] coins = { "Penny", "nickel", "dime", 
      "Quarter", "dollar" };
      Set set = new TreeSet();
      for (int i = 0; i < coins.length; i++)
         set.add(coins[i]);
      System.out.println(Collections.min(set));
      System.out.println(Collections.min(set, String.CASE_INSENSITIVE_ORDER));
      for(int i=0;i<=10;i++)
         System.out.print("-");
      System.out.println("");
      System.out.println(Collections.max(set));
      System.out.println(Collections.max(set, String.CASE_INSENSITIVE_ORDER));
   }
}

Penny
dime
-----------
nickel
Quarter