OpenJDK 1.23 · java.util · APIdia, the JavaDoc alternative

Interface Summary

Modifier and Type	Interface and Description
public interface	Collection< the type of elements in this collection E> The root interface in the collection hierarchy.
public interface	Comparator< the type of objects that may be compared by this comparator T> A comparison function, which imposes a total ordering on some collection of objects.
public interface	Deque< the type of elements held in this deque E> A linear collection that supports element insertion and removal at both ends.
public interface	Enumeration< the type of elements returned by this enumeration E> An object that implements the Enumeration interface generates a series of elements, one at a time.
public interface	EventListener A tagging interface that all event listener interfaces must extend.
public interface	Formattable The `Formattable` interface must be implemented by any class that needs to perform custom formatting using the `'s'` conversion specifier of `java.util.Formatter`.
public interface	Iterator< the type of elements returned by this iterator E> An iterator over a collection.
public interface	List< the type of elements in this list E> An ordered collection, where the user has precise control over where in the list each element is inserted.
public interface	ListIterator< the type of elements returned by this list iterator 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.
public interface	Map< the type of keys maintained by this map K, the type of mapped values V> An object that maps keys to values.
public interface	NavigableMap< the type of keys maintained by this map K, the type of mapped values V> A `SortedMap` extended with navigation methods returning the closest matches for given search targets.
public interface	NavigableSet< the type of elements maintained by this set E> A `SortedSet` extended with navigation methods reporting closest matches for given search targets.
public interface	Observer Deprecated since 9. This interface has been deprecated. See the `Observable` class for further information. A class can implement the `Observer` interface when it wants to be informed of changes in observable objects.
public interface	PrimitiveIterator< the type of elements returned by this PrimitiveIterator. The type must be a wrapper type for a primitive type, such as `Integer` for the primitive `int` type. T, the type of primitive consumer. The type must be a primitive specialization of `java.util.function.Consumer` for `T`, such as `java.util.function.IntConsumer` for `Integer`. T_CONS> A base type for primitive specializations of `Iterator`.
public interface	Queue< the type of elements held in this queue E> A collection designed for holding elements prior to processing.
public interface	RandomAccess Marker interface used by `List` implementations to indicate that they support fast (generally constant time) random access.
public interface	SequencedCollection< the type of elements in this collection E> A collection that has a well-defined encounter order, that supports operations at both ends, and that is reversible.
public interface	SequencedMap< the type of keys maintained by this map K, the type of mapped values V> A Map that has a well-defined encounter order, that supports operations at both ends, and that is reversible.
public interface	SequencedSet< the type of elements in this sequenced set E> A collection that is both a `SequencedCollection` and a `Set`.
public interface	Set< the type of elements maintained by this set E> A collection that contains no duplicate elements.
public interface	SortedMap< the type of keys maintained by this map K, the type of mapped values V> A `Map` that further provides a total ordering on its keys.
public interface	SortedSet< the type of elements maintained by this set E> A `Set` that further provides a total ordering on its elements.
public interface	Spliterator< the type of elements returned by this Spliterator T> An object for traversing and partitioning elements of a source.

Class Summary

Modifier and Type	Class and Description
public abstract class	AbstractCollection< the type of elements in this collection E> This class provides a skeletal implementation of the `Collection` interface, to minimize the effort required to implement this interface.
public abstract class	AbstractList< the type of elements in this list E> 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).
public abstract class	AbstractMap< the type of keys maintained by this map K, the type of mapped values V> This class provides a skeletal implementation of the `Map` interface, to minimize the effort required to implement this interface.
public abstract class	AbstractQueue< the type of elements held in this queue E> This class provides skeletal implementations of some `Queue` operations.
public abstract class	AbstractSequentialList< the type of elements in this list E> 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).
public abstract class	AbstractSet< the type of elements maintained by this set E> This class provides a skeletal implementation of the `Set` interface to minimize the effort required to implement this interface.
public class	ArrayDeque< the type of elements held in this deque E> Resizable-array implementation of the `Deque` interface.
public class	ArrayList< the type of elements in this list E> Resizable-array implementation of the `List` interface.
pack-priv class	ArrayPrefixHelpers ForkJoin tasks to perform Arrays.parallelPrefix operations.
public class	Arrays This class contains various methods for manipulating arrays (such as sorting and searching).
pack-priv class	ArraysParallelSortHelpers Helper utilities for the parallel sort methods in Arrays.parallelSort.
public class	Base64 This class consists exclusively of static methods for obtaining encoders and decoders for the Base64 encoding scheme.
public class	BitSet This class implements a vector of bits that grows as needed.
public abstract class	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.
public class	Collections This class consists exclusively of static methods that operate on or return collections.
pack-priv class	CollSer A unified serialization proxy class for the immutable collections.
pack-priv class	ComparableTimSort This is a near duplicate of `TimSort`, modified for use with arrays of objects that implement `Comparable`, instead of using explicit comparators.
pack-priv class	Comparators Package private supporting class for `Comparator`.
public class	ConcurrentModificationException This exception may be thrown by methods that have detected concurrent modification of an object when such modification is not permissible.
public class	Currency Represents a currency.
public class	Date The class `Date` represents a specific instant in time, with millisecond precision.
public abstract class	Dictionary< the type of keys K, the type of mapped values V> The `Dictionary` class is the abstract parent of any class, such as `Hashtable`, which maps keys to values.
public class	DoubleSummaryStatistics A state object for collecting statistics such as count, min, max, sum, and average.
pack-priv class	DualPivotQuicksort This class implements powerful and fully optimized versions, both sequential and parallel, of the Dual-Pivot Quicksort algorithm by Vladimir Yaroslavskiy, Jon Bentley and Josh Bloch.
public class	DuplicateFormatFlagsException Unchecked exception thrown when duplicate flags are provided in the format specifier.
public class	EmptyStackException Thrown by methods in the `Stack` class to indicate that the stack is empty.
public class	EnumMap< the enum type of keys maintained by this map K extends Enum<K>, the type of mapped values V> A specialized `Map` implementation for use with enum type keys.
public abstract class	EnumSet< the enum type of elements maintained by this set E extends Enum<E>> A specialized `Set` implementation for use with enum types.
public abstract class	EventListenerProxy< the type of `EventListener` being wrapped T extends EventListener> An abstract wrapper class for an `EventListener` class which associates a set of additional parameters with the listener.
public class	EventObject The root class from which all event state objects shall be derived.
public class	FormatFlagsConversionMismatchException Unchecked exception thrown when a conversion and flag are incompatible.
public class	FormattableFlags FormattableFlags are passed to the `Formattable.formatTo()` method and modify the output format for Formattables.
public class	Formatter An interpreter for printf-style format strings.
public class	FormatterClosedException Unchecked exception thrown when the formatter has been closed.
public class	GregorianCalendar `GregorianCalendar` is a concrete subclass of `Calendar` and provides the standard calendar system used by most of the world.
public class	HashMap< the type of keys maintained by this map K, the type of mapped values V> Hash table based implementation of the `Map` interface.
public class	HashSet< the type of elements maintained by this set E> This class implements the `Set` interface, backed by a hash table (actually a `HashMap` instance).
public class	Hashtable< the type of keys maintained by this map K, the type of mapped values V> This class implements a hash table, which maps keys to values.
public class	HexFormat `HexFormat` converts between bytes and chars and hex-encoded strings which may include additional formatting markup such as prefixes, suffixes, and delimiters.
public class	IdentityHashMap< the type of keys maintained by this map K, the type of mapped values V> This class implements the `Map` interface with a hash table, using reference-equality in place of object-equality when comparing keys (and values).
pack-priv class	IllegalFormatArgumentIndexException Unchecked exception thrown when the argument index is not within the valid range of supported argument index values.
public class	IllegalFormatCodePointException Unchecked exception thrown when a character with an invalid Unicode code point as defined by `Character#isValidCodePoint` is passed to the `Formatter`.
public class	IllegalFormatConversionException Unchecked exception thrown when the argument corresponding to the format specifier is of an incompatible type.
public class	IllegalFormatException Unchecked exception thrown when a format string contains an illegal syntax or a format specifier that is incompatible with the given arguments.
public class	IllegalFormatFlagsException Unchecked exception thrown when an illegal combination flags is given.
public class	IllegalFormatPrecisionException Unchecked 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.
public class	IllegalFormatWidthException Unchecked exception thrown when the format width is a negative value other than `-1` or is otherwise unsupported.
public class	IllformedLocaleException Thrown by methods in `Locale` and `Locale.Builder` to indicate that an argument is not a well-formed BCP 47 tag.
pack-priv class	ImmutableCollections Container class for immutable collections.
public class	InputMismatchException Thrown by a `Scanner` to 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.
public class	IntSummaryStatistics A state object for collecting statistics such as count, min, max, sum, and average.
public class	InvalidPropertiesFormatException Thrown 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 `Properties` specification.
pack-priv class	JapaneseImperialCalendar `JapaneseImperialCalendar` implements a Japanese calendar system in which the imperial era-based year numbering is supported from the Meiji era.
pack-priv class	JumboEnumSet<E extends Enum<E>> Private implementation class for EnumSet, for "jumbo" enum types (i.e., those with more than 64 elements).
pack-priv class	KeyValueHolder< the key type K, the value type V> An immutable container for a key and a value, suitable for use in creating and populating `Map` instances.
public class	LinkedHashMap< the type of keys maintained by this map K, the type of mapped values V> Hash table and linked list implementation of the `Map` interface, with well-defined encounter order.
public class	LinkedHashSet< the type of elements maintained by this set E> Hash table and linked list implementation of the `Set` interface, with well-defined encounter order.
public class	LinkedList< the type of elements held in this collection E> Doubly-linked list implementation of the `List` and `Deque` interfaces.
public abstract class	ListResourceBundle `ListResourceBundle` is an abstract subclass of `ResourceBundle` that manages resources for a locale in a convenient and easy to use list.
public class	Locale A `Locale` object represents a specific geographical, political, or cultural region.
pack-priv class	LocaleISOData
public class	LongSummaryStatistics A state object for collecting statistics such as count, min, max, sum, and average.
public class	MissingFormatArgumentException Unchecked 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.
public class	MissingFormatWidthException Unchecked exception thrown when the format width is required.
public class	MissingResourceException Signals that a resource is missing.
public class	NoSuchElementException Thrown by various accessor methods to indicate that the element being requested does not exist.
public class	Objects This class consists of `static` utility methods for operating on objects, or checking certain conditions before operation.
public class	Observable Deprecated since 9. This class and the `Observer` interface have been deprecated. This class represents an observable object, or "data" in the model-view paradigm.
public class	Optional< the type of value T> A container object which may or may not contain a non-`null` value.
public class	OptionalDouble A container object which may or may not contain a `double` value.
public class	OptionalInt A container object which may or may not contain an `int` value.
public class	OptionalLong A container object which may or may not contain a `long` value.
public class	PriorityQueue< the type of elements held in this queue E> An unbounded priority queue based on a priority heap.
public class	Properties The `Properties` class represents a persistent set of properties.
public class	PropertyPermission This class is for property permissions.
pack-priv class	PropertyPermissionCollection A PropertyPermissionCollection stores a set of PropertyPermission permissions.
public class	PropertyResourceBundle `PropertyResourceBundle` is a concrete subclass of `ResourceBundle` that manages resources for a locale using a set of static strings from a property file.
public class	Random An instance of this class is used to generate a stream of pseudorandom numbers; its period is only 2⁴⁸.
pack-priv class	RegularEnumSet<E extends Enum<E>> Private implementation class for EnumSet, for "regular sized" enum types (i.e., those with 64 or fewer enum constants).
public abstract class	ResourceBundle Resource bundles contain locale-specific objects.
pack-priv class	ReverseOrderDequeView<E> Provides a reverse-ordered view of any Deque.
pack-priv class	ReverseOrderListView<E> Provides a reverse-ordered view of a List.
pack-priv class	ReverseOrderSortedMapView<K, V> Provides a reversed-ordered view of a SortedMap.
pack-priv class	ReverseOrderSortedSetView<E> Provides a reversed-ordered view of a SortedSet.
public class	Scanner A simple text scanner which can parse primitive types and strings using regular expressions.
public class	ServiceConfigurationError Error thrown when something goes wrong while locating, loading, or instantiating a service provider.
public class	ServiceLoader< The type of the service to be loaded by this loader S> A facility to load implementations of a service.
public class	SimpleTimeZone `SimpleTimeZone` is a concrete subclass of `TimeZone` that represents a time zone for use with a Gregorian calendar.
public class	Spliterators Static classes and methods for operating on or creating instances of `Spliterator` and its primitive specializations `Spliterator.OfInt`, `Spliterator.OfLong`, and `Spliterator.OfDouble`.
public class	SplittableRandom A generator of uniform pseudorandom values (with period 2⁶⁴) applicable for use in (among other contexts) isolated parallel computations that may generate subtasks.
public class	Stack< Type of component elements E> The `Stack` class represents a last-in-first-out (LIFO) stack of objects.
public class	StringJoiner `StringJoiner` is used to construct a sequence of characters separated by a delimiter and optionally starting with a supplied prefix and ending with a supplied suffix.
public class	StringTokenizer The string tokenizer class allows an application to break a string into tokens.
pack-priv class	TaskQueue This class represents a timer task queue: a priority queue of TimerTasks, ordered on nextExecutionTime.
public class	Timer A facility for threads to schedule tasks for future execution in a background thread.
public abstract class	TimerTask A task that can be scheduled for one-time or repeated execution by a `Timer`.
pack-priv class	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.
public abstract class	TimeZone `TimeZone` represents a time zone offset, and also figures out daylight savings.
pack-priv class	TimSort<T> A stable, adaptive, iterative mergesort that requires far fewer than n lg(n) comparisons when running on partially sorted arrays, while offering performance comparable to a traditional mergesort when run on random arrays.
public class	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.
public class	TreeMap< the type of keys maintained by this map K, the type of mapped values V> A Red-Black tree based `NavigableMap` implementation.
public class	TreeSet< the type of elements maintained by this set E> A `NavigableSet` implementation based on a `TreeMap`.
pack-priv class	Tripwire Utility class for detecting inadvertent uses of boxing in `java.util` classes.
public class	UnknownFormatConversionException Unchecked exception thrown when an unknown conversion is given.
public class	UnknownFormatFlagsException Unchecked exception thrown when an unknown flag is given.
public class	UUID A class that represents an immutable universally unique identifier (UUID).
public class	Vector< Type of component elements E> The `Vector` class implements a growable array of objects.
public class	WeakHashMap< the type of keys maintained by this map K, the type of mapped values V> Hash table based implementation of the `Map` interface, with weak keys.

Package java.util

Java Collections Framework

Interface Summary

Class Summary