void (String[] args) { Collections unmodifiableCollection = Collections.EMPTY_LIST; List unmodifiableList = Collections.EMPTY_LIST; Set unmodifiableSet = Collections.EMPTY_SET; Map unmodifiableMap = Collections.EMPTY_MAP; SortedSet unmodifiableSortedSet = Collections.EMPTY_SET; SortedMap unmodifiableSortedMap = Collections.EMPTY_MAP; NavigableSet unmodifiableNavigableSet = Collections.EMPTY_SET; NavigableMap unmodifiableNavigableMap = Collections.EMPTY_MAP; }