Contains the collections framework, some internationalization support classes, a service loader, properties, random number generation, string parsing and scanning classes, base64 encoding and decoding, a bit array, and several miscellaneous utility classes. This package also contains legacy collection classes and legacy date and time classes.
For an overview, API outline, and design rationale, please see:
For a tutorial and programming guide with examples of use of the collections framework, please see:
Interface Summary Interface Description Collection<E>The root interface in the collection hierarchy. Comparator<T>A comparison function, which imposes a total ordering on some collection of objects. Deque<E>A linear collection that supports element insertion and removal at both ends. Enumeration<E>An object that implements the Enumeration interface generates a series of elements, one at a time. EventListenerA tagging interface that all event listener interfaces must extend. FormattableThe
Formattableinterface must be implemented by any class that needs to perform custom formatting using the
's'conversion specifier of
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). NavigableMap<K,V>A
SortedMapextended with navigation methods returning the closest matches for given search targets.
SortedSetextended with navigation methods reporting closest matches for given search targets.
Observer Deprecated.This interface has been deprecated. PrimitiveIterator<T,T_CONS>A base type for primitive specializations of
PrimitiveIterator.OfDoubleAn Iterator specialized for
PrimitiveIterator.OfIntAn Iterator specialized for
PrimitiveIterator.OfLongAn Iterator specialized for
Queue<E>A collection designed for holding elements prior to processing. RandomAccessMarker interface used by
Listimplementations to indicate that they support fast (generally constant time) random access.
ServiceLoader.Provider<S>Represents a service provider located by
Set<E>A collection that contains no duplicate elements. SortedMap<K,V>A
Mapthat further provides a total ordering on its keys.
Setthat further provides a total ordering on its elements.
Spliterator<T>An object for traversing and partitioning elements of a source. Spliterator.OfDoubleA Spliterator specialized for
Spliterator.OfIntA Spliterator specialized for
Spliterator.OfLongA Spliterator specialized for
Spliterator.OfPrimitive<T,T_CONS,T_SPLITR extends Spliterator.OfPrimitive<T,T_CONS,T_SPLITR>>A Spliterator specialized for primitive values.
Class Summary Class Description AbstractCollection<E>This class provides a skeletal implementation of the
Collectioninterface, to minimize the effort required to implement this interface.
AbstractList<E>This class provides a skeletal implementation of the
Listinterface to minimize the effort required to implement this interface backed by a "random access" data store (such as an array).
AbstractMap<K,V>This class provides a skeletal implementation of the
Mapinterface, 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. AbstractQueue<E>This class provides skeletal implementations of some
AbstractSequentialList<E>This class provides a skeletal implementation of the
Listinterface to minimize the effort required to implement this interface backed by a "sequential access" data store (such as a linked list).
AbstractSet<E>This class provides a skeletal implementation of the
Setinterface to minimize the effort required to implement this interface.
ArrayDeque<E>Resizable-array implementation of the
ArrayList<E>Resizable-array implementation of the
ArraysThis class contains various methods for manipulating arrays (such as sorting and searching). Base64This class consists exclusively of static methods for obtaining encoders and decoders for the Base64 encoding scheme. Base64.DecoderThis class implements a decoder for decoding byte data using the Base64 encoding scheme as specified in RFC 4648 and RFC 2045. Base64.EncoderThis class implements an encoder for encoding byte data using the Base64 encoding scheme as specified in RFC 4648 and RFC 2045. BitSetThis class implements a vector of bits that grows as needed. CalendarThe
Calendarclass is an abstract class that provides methods for converting between a specific instant in time and a set of
calendar fieldssuch as
HOUR, and so on, and for manipulating the calendar fields, such as getting the date of the next week.
Calendar.Builderis used for creating a
Calendarfrom various date-time parameters.
CollectionsThis class consists exclusively of static methods that operate on or return collections. CurrencyRepresents a currency. DateThe class
Daterepresents a specific instant in time, with millisecond precision.
Dictionaryclass is the abstract parent of any class, such as
Hashtable, which maps keys to values.
DoubleSummaryStatisticsA state object for collecting statistics such as count, min, max, sum, and average. EnumMap<K extends Enum<K>,V>A specialized
Mapimplementation for use with enum type keys.
EnumSet<E extends Enum<E>>A specialized
Setimplementation for use with enum types.
EventListenerProxy<T extends EventListener>An abstract wrapper class for an
EventListenerclass which associates a set of additional parameters with the listener.
EventObjectThe root class from which all event state objects shall be derived. FormattableFlags FormatterAn interpreter for printf-style format strings. GregorianCalendar
GregorianCalendaris a concrete subclass of
Calendarand provides the standard calendar system used by most of the world.
HashMap<K,V>Hash table based implementation of the
HashSet<E>This class implements the
Setinterface, backed by a hash table (actually a
Hashtable<K,V>This class implements a hash table, which maps keys to values. IdentityHashMap<K,V>This class implements the
Mapinterface with a hash table, using reference-equality in place of object-equality when comparing keys (and values).
IntSummaryStatisticsA state object for collecting statistics such as count, min, max, sum, and average. LinkedHashMap<K,V>Hash table and linked list implementation of the
Mapinterface, with predictable iteration order.
LinkedHashSet<E>Hash table and linked list implementation of the
Setinterface, with predictable iteration order.
LinkedList<E>Doubly-linked list implementation of the
ListResourceBundleis an abstract subclass of
ResourceBundlethat manages resources for a locale in a convenient and easy to use list.
Localeobject represents a specific geographical, political, or cultural region.
Builderis used to build instances of
Localefrom values configured by the setters.
Locale.LanguageRangeThis class expresses a Language Range defined in RFC 4647 Matching of Language Tags. LongSummaryStatisticsA state object for collecting statistics such as count, min, max, sum, and average. ObjectsThis class consists of
staticutility methods for operating on objects, or checking certain conditions before operation.
Observable Deprecated.This class and the
Observerinterface have been deprecated.
Optional<T>A container object which may or may not contain a non-
OptionalDoubleA container object which may or may not contain a
OptionalIntA container object which may or may not contain an
OptionalLongA container object which may or may not contain a
PriorityQueue<E>An unbounded priority queue based on a priority heap. PropertiesThe
Propertiesclass represents a persistent set of properties.
PropertyPermissionThis class is for property permissions. PropertyResourceBundle
PropertyResourceBundleis a concrete subclass of
ResourceBundlethat manages resources for a locale using a set of static strings from a property file.
RandomAn instance of this class is used to generate a stream of pseudorandom numbers. ResourceBundleResource bundles contain locale-specific objects. ResourceBundle.Control
ResourceBundle.Controldefines a set of callback methods that are invoked by the
ResourceBundle.getBundlefactory methods during the bundle loading process.
ScannerA simple text scanner which can parse primitive types and strings using regular expressions. ServiceLoader<S>A facility to load implementations of a service. SimpleTimeZone
SimpleTimeZoneis a concrete subclass of
TimeZonethat represents a time zone for use with a Gregorian calendar.
Spliterators Spliterators.AbstractDoubleSpliteratorAn abstract
trySplitto permit limited parallelism.
trySplitto permit limited parallelism.
trySplitto permit limited parallelism.
trySplitto permit limited parallelism.
SplittableRandomA generator of uniform pseudorandom values applicable for use in (among other contexts) isolated parallel computations that may generate subtasks. Stack<E>The
Stackclass represents a last-in-first-out (LIFO) stack of objects.
StringJoineris used to construct a sequence of characters separated by a delimiter and optionally starting with a supplied prefix and ending with a supplied suffix.
StringTokenizerThe string tokenizer class allows an application to break a string into tokens. TimerA facility for threads to schedule tasks for future execution in a background thread. TimerTaskA task that can be scheduled for one-time or repeated execution by a
TimeZonerepresents a time zone offset, and also figures out daylight savings.
TreeMap<K,V>A Red-Black tree based
TreeSet<E> UUIDA class that represents an immutable universally unique identifier (UUID). Vector<E>The
Vectorclass implements a growable array of objects.
WeakHashMap<K,V>Hash table based implementation of the
Mapinterface, with weak keys.
Enum Summary Enum Description Formatter.BigDecimalLayoutFormEnum for
Locale.CategoryEnum for locale categories. Locale.FilteringModeThis enum provides constants to select a filtering mode for locale matching. Locale.IsoCountryCodeEnum for specifying the type defined in ISO 3166.
Exception Summary Exception Description ConcurrentModificationExceptionThis exception may be thrown by methods that have detected concurrent modification of an object when such modification is not permissible. DuplicateFormatFlagsExceptionUnchecked exception thrown when duplicate flags are provided in the format specifier. EmptyStackExceptionThrown by methods in the
Stackclass to indicate that the stack is empty.
FormatFlagsConversionMismatchExceptionUnchecked exception thrown when a conversion and flag are incompatible. FormatterClosedExceptionUnchecked exception thrown when the formatter has been closed. IllegalFormatCodePointException IllegalFormatConversionExceptionUnchecked exception thrown when the argument corresponding to the format specifier is of an incompatible type. IllegalFormatExceptionUnchecked exception thrown when a format string contains an illegal syntax or a format specifier that is incompatible with the given arguments. IllegalFormatFlagsExceptionUnchecked exception thrown when an illegal combination flags is given. IllegalFormatPrecisionExceptionUnchecked exception thrown when the precision is a negative value other than
-1, the conversion does not support a precision, or the value is otherwise unsupported.
IllegalFormatWidthExceptionUnchecked exception thrown when the format width is a negative value other than
-1or is otherwise unsupported.
IllformedLocaleException InputMismatchExceptionThrown by a
Scannerto indicate that the token retrieved does not match the pattern for the expected type, or that the token is out of range for the expected type.
InvalidPropertiesFormatExceptionThrown to indicate that an operation could not complete because the input did not conform to the appropriate XML document type for a collection of properties, as per the
MissingFormatArgumentExceptionUnchecked exception thrown when there is a format specifier which does not have a corresponding argument or if an argument index refers to an argument that does not exist. MissingFormatWidthExceptionUnchecked exception thrown when the format width is required. MissingResourceExceptionSignals that a resource is missing. NoSuchElementExceptionThrown by various accessor methods to indicate that the element being requested does not exist. TooManyListenersExceptionThe
TooManyListenersExceptionException is used as part of the Java Event model to annotate and implement a unicast special case of a multicast Event Source.
UnknownFormatConversionExceptionUnchecked exception thrown when an unknown conversion is given. UnknownFormatFlagsExceptionUnchecked exception thrown when an unknown flag is given.
Error Summary Error Description ServiceConfigurationErrorError thrown when something goes wrong while locating, loading, or instantiating a service provider.