@NonNullByDefault

# Package java.util

Contains utility classes including the collections framework and date manipulation.

- Interface Summary
  Interface | Description
  --- | ---
  Collection<E> |
  Comparator<T> |
  Enumeration<E> | An object that implements the Enumeration interface generates a series of elements, one at a time.
  EventListener | A tagging interface that all event listener interfaces must extend.
  Iterator<E> | An iterator over a collection.
  List<E> | An ordered collection (also known as a sequence).
  ListIterator<E> | An iterator for lists that allows the programmer to traverse the list in either direction, modify the list during iteration, and obtain the iterator's current position in the list.
  Map<K,​V> | An object that maps keys to values.
  Map.Entry<K,​V> | A map entry (key-value pair).
  Observer | A class can implement the `Observer` interface when it wants to be informed of changes in observable objects.
  RandomAccess | Marker interface used by `List` implementations to indicate that they support fast (generally constant time) random access.
  Set<E> |

- Class Summary
  Class | Description
  --- | ---
  AbstractCollection<E> |
  AbstractList<E> |
  AbstractMap<K,​V> | This class provides a skeletal implementation of the `Map` interface, to minimize the effort required to implement this interface.
  AbstractMap.SimpleEntry<K,​V> | An Entry maintaining a key and a value.
  AbstractMap.SimpleImmutableEntry<K,​V> | An Entry maintaining an immutable key and value.
  AbstractSet<E> |
  ArrayList<E> |
  Calendar | The `Calendar` class is an abstract class that provides methods for converting between a specific instant in time and a set of `calendar fields` such as `YEAR` , `MONTH` , `DAY_OF_MONTH`, `HOUR`, and so on, and for manipulating the calendar fields, such as getting the date of the next week.
  Date | The class `Date` represents a specific instant in time, with millisecond precision.
  Dictionary<K,​V> | The `Dictionary` class is the abstract parent of any class, such as `Hashtable`, which maps keys to values.
  EventObject | The root class from which all event state objects shall be derived.
  HashMap<K,​V> | Hash table based implementation of the `Map` interface.
  Hashtable<K,​V> | This class implements a hash table, which maps keys to values.
  Observable | This class represents an observable object, or "data" in the model-view paradigm.
  PropertyPermission |
  Random | An instance of this class is used to generate a stream of pseudorandom numbers.
  Stack<E> | The `Stack` class represents a last-in-first-out (LIFO) stack of objects.
  Timer | Deprecated. Please consider `ej.bon.Timer` from BON specification instead.
  TimerTask | Deprecated. Please consider `ej.bon.TimerTask` from BON specification instead.
  TimeZone | `TimeZone` represents a time zone offset, and also figures out daylight savings.
  Vector<E> | The `Vector` class implements a growable array of objects.
  WeakHashMap<K,​V> | Hash table based implementation of the `Map` interface, with weak keys.

- Exception Summary
  Exception | Description
  --- | ---
  ConcurrentModificationException | This exception may be thrown by methods that have detected concurrent modification of an object when such modification is not permissible.
  EmptyStackException | Thrown by methods in the `Stack` class to indicate that the stack is empty.
  NoSuchElementException | Thrown by the `nextElement` method of an `Enumeration` to indicate that there are no more elements in the enumeration.