Package java.util

Interface Summary

Collection	The root interface in the collection hierarchy.
Comparator	A comparison function, which imposes a total ordering on some collection of objects.
Enumeration	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	An iterator over a collection.
List	An ordered collection (also known as a sequence).
ListIterator	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	An object that maps keys to values.
Map.Entry	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	A collection that contains no duplicate elements.
SortedMap	A map that further guarantees that it will be in ascending key order, sorted according to the natural ordering of its keys (see the Comparable interface), or by a comparator provided at sorted map creation time.
SortedSet	A set that further guarantees that its iterator will traverse the set in ascending element order, sorted according to the natural ordering of its elements (see Comparable), or by a Comparator provided at sorted set creation time.

Class Summary

AbstractCollection	This class provides a skeletal implementation of the Collection interface, to minimize the effort required to implement this interface.
AbstractList	This class provides a skeletal implementation of the List interface to minimize the effort required to implement this interface backed by a "random access" data store (such as an array).
AbstractMap	This class provides a skeletal implementation of the Map interface, to minimize the effort required to implement this interface.
AbstractMap.SimpleEntry	This should be made public as soon as possible.
AbstractSequentialList	This class provides a skeletal implementation of the List interface to minimize the effort required to implement this interface backed by a "sequential access" data store (such as a linked list).
AbstractSet	This class provides a skeletal implementation of the Set interface to minimize the effort required to implement this interface.
ArrayList	Resizable-array implementation of the List interface.
Arrays	This class contains various methods for manipulating arrays (such as sorting and searching).
Arrays.ArrayList
BitSet	This class implements a vector of bits that grows as needed.
Calendar	Calendar is an abstract base class for converting between a Date object and a set of integer fields such as YEAR, MONTH, DAY, HOUR, and so on.
Collections	This class consists exclusively of static methods that operate on or return collections.
Collections.CopiesList
Collections.EmptyList
Collections.EmptyMap
Collections.EmptySet
Collections.ReverseComparator
Collections.SingletonList
Collections.SingletonMap
Collections.SingletonMap.ImmutableEntry
Collections.SingletonSet
Collections.SynchronizedCollection
Collections.SynchronizedList
Collections.SynchronizedMap
Collections.SynchronizedRandomAccessList
Collections.SynchronizedSet
Collections.SynchronizedSortedMap
Collections.SynchronizedSortedSet
Collections.UnmodifiableCollection
Collections.UnmodifiableList
Collections.UnmodifiableMap
Collections.UnmodifiableMap.UnmodifiableEntrySet	We need this class in addition to UnmodifiableSet as Map.Entries themselves permit modification of the backing Map via their setValue operation.
Collections.UnmodifiableMap.UnmodifiableEntrySet.UnmodifiableEntry	This "wrapper class" serves two purposes: it prevents the client from modifying the backing Map, by short-circuiting the setValue method, and it protects the backing Map against an ill-behaved Map.Entry that attempts to modify another Map Entry when asked to perform an equality check.
Collections.UnmodifiableRandomAccessList
Collections.UnmodifiableSet
Collections.UnmodifiableSortedMap
Collections.UnmodifiableSortedSet
Currency	Represents a currency.
CurrencyData
Date	The class Date represents a specific instant in time, with millisecond precision.
Dictionary	The Dictionary class is the abstract parent of any class, such as Hashtable, which maps keys to values.
EventListenerProxy	An abstract wrapper class for an EventListener class which associates a set of additional parameters with the listener.
EventObject	The root class from which all event state objects shall be derived.
GregorianCalendar	GregorianCalendar is a concrete subclass of Calendar and provides the standard calendar used by most of the world.
HashMap	Hash table based implementation of the Map interface.
HashMap.Entry
HashSet	This class implements the Set interface, backed by a hash table (actually a HashMap instance).
Hashtable	This class implements a hashtable, which maps keys to values.
Hashtable.EmptyEnumerator	A hashtable enumerator class for empty hash tables, specializes the general Enumerator
Hashtable.EmptyIterator	A hashtable iterator class for empty hash tables
Hashtable.Entry	Hashtable collision list.
IdentityHashMap	This class implements the Map interface with a hash table, using reference-equality in place of object-equality when comparing keys (and values).
LinkedHashMap	Hash table and linked list implementation of the Map interface, with predictable iteration order.
LinkedHashMap.Entry	LinkedHashMap entry.
LinkedHashSet	Hash table and linked list implementation of the Set interface, with predictable iteration order.
LinkedList	Linked list implementation of the List interface.
LinkedList.Entry
ListResourceBundle	ListResourceBundle is an abstract subclass of ResourceBundle that manages resources for a locale in a convenient and easy to use list.
Locale	A Locale object represents a specific geographical, political, or cultural region.
Observable	This class represents an observable object, or "data" in the model-view paradigm.
Properties	The Properties class represents a persistent set of properties.
PropertyPermission	This class is for property permissions.
PropertyPermissionCollection	A PropertyPermissionCollection stores a set of PropertyPermission permissions.
PropertyResourceBundle	PropertyResourceBundle is a concrete subclass of ResourceBundle that manages resources for a locale using a set of static strings from a property file.
Random	An instance of this class is used to generate a stream of pseudorandom numbers.
RandomAccessSubList
ResourceBundle	Resource bundles contain locale-specific objects.
ResourceBundle.ResourceCacheKey	Key used for cached resource bundles.
ResourceBundleEnumeration	Implements an Enumeration that combines elements from a Set and an Enumeration.
SimpleTimeZone	SimpleTimeZone is a concrete subclass of TimeZone that represents a time zone for use with a Gregorian calendar.
Stack	The Stack class represents a last-in-first-out (LIFO) stack of objects.
StringTokenizer	The string tokenizer class allows an application to break a string into tokens.
SubList
TaskQueue	This class represents a timer task queue: a priority queue of TimerTasks, ordered on nextExecutionTime.
Timer	A facility for threads to schedule tasks for future execution in a background thread.
TimerTask	A task that can be scheduled for one-time or repeated execution by a Timer.
TimerThread	This "helper class" implements the timer's task execution thread, which waits for tasks on the timer queue, executions them when they fire, reschedules repeating tasks, and removes cancelled tasks and spent non-repeating tasks from the queue.
TimeZone	TimeZone represents a time zone offset, and also figures out daylight savings.
TreeMap	Red-Black tree based implementation of the SortedMap interface.
TreeMap.Entry	Node in the Tree.
TreeSet	This class implements the Set interface, backed by a TreeMap instance.
Vector	The Vector class implements a growable array of objects.
WeakHashMap	A hashtable-based Map implementation with weak keys.
WeakHashMap.Entry	The entries in this hash table extend WeakReference, using its main ref field as the key.

Exception Summary

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.
MissingResourceException	Signals that a resource is missing.
NoSuchElementException	Thrown by the nextElement method of an Enumeration to indicate that there are no more elements in the enumeration.
TooManyListenersException	The TooManyListenersException Exception is used as part of the Java Event model to annotate and implement a unicast special case of a multicast Event Source.