Package java.util

Utility classes such as collections (maps, sets, lists, dictionaries and stacks), calendars, dates, locales, properties, timers, resource bundles and event objects.

Interface Summary

Collection Interface that represents a collection of objects.
Comparator Interface for objects that specify an ordering between objects.
Enumeration Interface for lists of objects that can be returned in sequence.
EventListener Empty interface that is implemented by classes that need to receive events.
Iterator An object which iterates over a collection.
List An ordered collection (also known as a list).
ListIterator An extended version of Iterator to support the extra features of Lists.
Map An object that maps keys onto values.
Map.Entry A map entry (key-value pair).
Observer Interface that is implemented when a class wants to be informed of changes in Observable objects.
RandomAccess Marker interface used to inform List implementations that they support fast (usually constant time) random access.
Set A collection that contains no duplicates.
SortedMap A map which guarantees its key's iteration order.
SortedSet A set which guarantees its iteration order.

Class Summary

AbstractCollection A basic implementation of most of the methods in the Collection interface to make it easier to create a collection.
AbstractList A basic implementation of most of the methods in the List interface to make it easier to create a List based on a random-access data structure.
AbstractMap An abstract implementation of Map to make it easier to create your own implementations.
AbstractSequentialList Abstract superclass to make it easier to implement the List interface when backed by a sequential-access store, such as a linked list.
AbstractSet An abstract implementation of Set to make it easier to create your own implementations.
ArrayList An array-backed implementation of the List interface.
Arrays This class contains various static utility methods performing operations on arrays, and a method to provide a List "view" of an array to facilitate using arrays with Collection-based APIs.
BitSet This class can be thought of in two ways.
Calendar This class is an abstract base class for Calendars, which can be used to convert between Date objects and a set of integer fields which represent YEAR, MONTH, DAY, etc.
Collections Utility class consisting of static methods that operate on, or return Collections.
Currency Representation of a currency for a particular locale.
Date This class represents a specific time in milliseconds since the epoch.
Dictionary A Dictionary maps keys to values; how it does that is implementation-specific.
EventListenerProxy An abstract wrapper for event listeners.
EventObject Represents Events fired by Objects.
GregorianCalendar This class represents the Gregorian calendar, that is used in most countries all over the world.
HashMap This class provides a hashtable-backed implementation of the Map interface.
HashSet This class provides a HashMap-backed implementation of the Set interface.
Hashtable A class which implements a hashtable data structure.
IdentityHashMap This class provides a hashtable-backed implementation of the Map interface, but uses object identity to do its hashing.
LinkedHashMap This class provides a hashtable-backed implementation of the Map interface, with predictable traversal order.
LinkedHashSet This class provides a hashtable-backed implementation of the Set interface, with predictable traversal order.
LinkedList Linked list implementation of the List interface.
ListResourceBundle A ListResouceBundle provides an easy way, to create your own resource bundle.
Locale Locales represent a specific country and culture.
Observable This class represents an object which is observable.
Properties A set of persistent properties, which can be saved or loaded from a stream.
PropertyPermission This class represents the permission to access and modify a property.
The name is the name of the property, e.g. xxx.
PropertyResourceBundle This class is a concrete ResourceBundle that gets it resources from a property file.
Random This class generates pseudorandom numbers.
ResourceBundle A resource bundle contains locale-specific data.
SimpleTimeZone This class represents a simple time zone offset and handles daylight savings.
Stack
StringTokenizer This class splits a string into tokens.
Timer Timer that can run TimerTasks at a later time.
TimerTask Task that can be run at a later time if given to a Timer.
TimeZone This class represents a time zone offset and handles daylight savings.
TreeMap This class provides a red-black tree implementation of the SortedMap interface.
TreeSet This class provides a TreeMap-backed implementation of the SortedSet interface.
Vector The Vector classes implements growable arrays of Objects.
WeakHashMap A weak hash map has only weak references to the key.

Exception Summary

ConcurrentModificationException Exception that is thrown by the collections classes when it is detected that a modification has been made to a data structure when this is not allowed, such as when a collection is structurally modified while an Iterator is operating over it.
EmptyStackException This exception is thrown by the Stack class when an attempt is made to pop or otherwise access elements from an empty stack.
InvalidPropertiesFormatException
MissingResourceException This exception is thrown when a resource is missing.
NoSuchElementException Exception thrown when an attempt is made to access an element that does not exist.
TooManyListenersException This exception is part of the java event model.
Utility classes such as collections (maps, sets, lists, dictionaries and stacks), calendars, dates, locales, properties, timers, resource bundles and event objects.