// Making collections unmodifiable
Collection<C> x =  Collections.unmodifiableCollection( someCollection );
List<V> x =        Collections.unmodifiableList( someMap );
Map<K,V> x =       Collections.unmodifiableMap( someMap );
Set<S> x =         Collections.unmodifiableSet( someSet );
SortedMap<K,V> x = Collections.unmodifiableSortedMap( someSortedMap );