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 {
main(String[] args)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