Collection Java Book

static Collection unmodifiableCollection(Collection c)
Returns an unmodifiable view of the specified collection.
static List unmodifiableList(List list)
Returns an unmodifiable view of the specified list.
static Map unmodifiableMap(Map m)
Returns an unmodifiable view of the specified map.
static Set unmodifiableSet(Set s)
Returns an unmodifiable view of the specified set.
static SortedMap unmodifiableSortedMap(SortedMap m)
Returns an unmodifiable view of the specified sorted map.
static SortedSet unmodifiableSortedSet(SortedSet s)
Returns an unmodifiable view of the specified sorted set.
Revised from Open JDK source code