Java Tutorial/Collections/Wrapped Collections

Read-Only Collections

   <source lang="java">

public static Collection unmodifiableCollection(Collection c) public static List unmodifiableList(List l) public static Map unmodifiableMap(Map m) public static Set unmodifiableSet(Set s) public static SortedMap unmodifiableSortedMap(SortedMap m) public static SortedSet unmodifiableSortedSet(SortedSet s)</source>

Exception in thread "main" java.lang.UnsupportedOperationException
  at java.util.Collections$UnmodifiableCollection.clear(Collections.java:1037)
  at MainClass.main(MainClass.java:20)