1 import java.nio.charset.Charset; 2 import java.util.ArrayList; 3 import java.util.Arrays; 4 import java.util.Collections; 5 import java.util.HashSet; 6 import java.util.List; 7 import java.util.Map; 8 import java.util.SortedMap; 9 import java.util.Set; 10 11 public class Main { 12 static public void main(String[] args) throws Exception { 13 // These charsets must be provided; anything else is optional. 14 List<String> standardCharsets = Arrays.asList("US-ASCII", "ISO-8859-1", 15 "UTF-8", "UTF-16BE", "UTF-16LE", "UTF-16"); 16 17 SortedMap<String, Charset> all = Charset.availableCharsets(); 18 Set<String> needed = new HashSet<String>(standardCharsets); 19 for (Map.Entry<String, Charset> e : all.entrySet()) { 20 String canonicalName = e.getKey(); 21 needed.remove(canonicalName); 22 } 23 System.out.println("Missing: " + needed); 24 } 25 } 26
