Added in [API level 1](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

# java.util

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.

## "Java Collections Framework"

For an overview, API outline, and design rationale, please see:

- [**Collections Framework Documentation**](https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/doc-files/coll-index.html)

For a tutorial and programming guide with examples of use
of the collections framework, please see:

- [**Collections Framework Tutorial**](http://docs.oracle.com/javase/tutorial/collections/index.html)

## Interfaces

|---|---|
| [Collection](https://developer.android.com/reference/java/util/Collection)\<E\> | The root interface in the *collection hierarchy*. |
| [Comparator](https://developer.android.com/reference/java/util/Comparator)\<T\> | A comparison function, which imposes a *total ordering* on some collection of objects. |
| [Deque](https://developer.android.com/reference/java/util/Deque)\<E\> | A linear collection that supports element insertion and removal at both ends. |
| [Enumeration](https://developer.android.com/reference/java/util/Enumeration)\<E\> | An object that implements the Enumeration interface generates a series of elements, one at a time. |
| [EventListener](https://developer.android.com/reference/java/util/EventListener) | A tagging interface that all event listener interfaces must extend. |
| [Formattable](https://developer.android.com/reference/java/util/Formattable) | The `Formattable` interface must be implemented by any class that needs to perform custom formatting using the `'s'` conversion specifier of `https://developer.android.com/reference/java/util/Formatter`. |
| [Iterator](https://developer.android.com/reference/java/util/Iterator)\<E\> | An iterator over a collection. |
| [List](https://developer.android.com/reference/java/util/List)\<E\> | An ordered collection, where the user has precise control over where in the list each element is inserted. |
| [ListIterator](https://developer.android.com/reference/java/util/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](https://developer.android.com/reference/java/util/Map)\<K, V\> | An object that maps keys to values. |
| [Map.Entry](https://developer.android.com/reference/java/util/Map.Entry)\<K, V\> | A map entry (key-value pair). |
| [NavigableMap](https://developer.android.com/reference/java/util/NavigableMap)\<K, V\> | A `https://developer.android.com/reference/java/util/SortedMap` extended with navigation methods returning the closest matches for given search targets. |
| [NavigableSet](https://developer.android.com/reference/java/util/NavigableSet)\<E\> | A `https://developer.android.com/reference/java/util/SortedSet` extended with navigation methods reporting closest matches for given search targets. |
| [Observer](https://developer.android.com/reference/java/util/Observer) | *This interface was deprecated in API level 33. This interface has been deprecated. See the `https://developer.android.com/reference/java/util/Observable` class for further information.* |
| [PrimitiveIterator](https://developer.android.com/reference/java/util/PrimitiveIterator)\<T, T_CONS\> | A base type for primitive specializations of `Iterator`. |
| [PrimitiveIterator.OfDouble](https://developer.android.com/reference/java/util/PrimitiveIterator.OfDouble) | An Iterator specialized for `double` values. |
| [PrimitiveIterator.OfInt](https://developer.android.com/reference/java/util/PrimitiveIterator.OfInt) | An Iterator specialized for `int` values. |
| [PrimitiveIterator.OfLong](https://developer.android.com/reference/java/util/PrimitiveIterator.OfLong) | An Iterator specialized for `long` values. |
| [Queue](https://developer.android.com/reference/java/util/Queue)\<E\> | A collection designed for holding elements prior to processing. |
| [RandomAccess](https://developer.android.com/reference/java/util/RandomAccess) | Marker interface used by `List` implementations to indicate that they support fast (generally constant time) random access. |
| [SequencedCollection](https://developer.android.com/reference/java/util/SequencedCollection)\<E\> | A collection that has a well-defined encounter order, that supports operations at both ends, and that is reversible. |
| [SequencedMap](https://developer.android.com/reference/java/util/SequencedMap)\<K, V\> | A Map that has a well-defined encounter order, that supports operations at both ends, and that is reversible. |
| [SequencedSet](https://developer.android.com/reference/java/util/SequencedSet)\<E\> | A collection that is both a `https://developer.android.com/reference/java/util/SequencedCollection` and a `https://developer.android.com/reference/java/util/Set`. |
| [ServiceLoader.Provider](https://developer.android.com/reference/java/util/ServiceLoader.Provider)\<S\> | Represents a service provider located by `ServiceLoader`. |
| [Set](https://developer.android.com/reference/java/util/Set)\<E\> | A collection that contains no duplicate elements. |
| [SortedMap](https://developer.android.com/reference/java/util/SortedMap)\<K, V\> | A `https://developer.android.com/reference/java/util/Map` that further provides a *total ordering* on its keys. |
| [SortedSet](https://developer.android.com/reference/java/util/SortedSet)\<E\> | A `https://developer.android.com/reference/java/util/Set` that further provides a *total ordering* on its elements. |
| [Spliterator](https://developer.android.com/reference/java/util/Spliterator)\<T\> | An object for traversing and partitioning elements of a source. |
| [Spliterator.OfDouble](https://developer.android.com/reference/java/util/Spliterator.OfDouble) | A Spliterator specialized for `double` values. |
| [Spliterator.OfInt](https://developer.android.com/reference/java/util/Spliterator.OfInt) | A Spliterator specialized for `int` values. |
| [Spliterator.OfLong](https://developer.android.com/reference/java/util/Spliterator.OfLong) | A Spliterator specialized for `long` values. |
| [Spliterator.OfPrimitive](https://developer.android.com/reference/java/util/Spliterator.OfPrimitive)\<T, T_CONS, T_SPLITR extends [OfPrimitive](https://developer.android.com/reference/java/util/Spliterator.OfPrimitive)\<T, T_CONS, T_SPLITR\>\> | A Spliterator specialized for primitive values. |

## Classes

|---|---|
| [AbstractCollection](https://developer.android.com/reference/java/util/AbstractCollection)\<E\> | This class provides a skeletal implementation of the `Collection` interface, to minimize the effort required to implement this interface. |
| [AbstractList](https://developer.android.com/reference/java/util/AbstractList)\<E\> | This class provides a skeletal implementation of the `https://developer.android.com/reference/java/util/List` interface to minimize the effort required to implement this interface backed by a "random access" data store (such as an array). |
| [AbstractMap](https://developer.android.com/reference/java/util/AbstractMap)\<K, V\> | This class provides a skeletal implementation of the `Map` interface, to minimize the effort required to implement this interface. |
| [AbstractMap.SimpleEntry](https://developer.android.com/reference/java/util/AbstractMap.SimpleEntry)\<K, V\> | An Entry maintaining a key and a value. |
| [AbstractMap.SimpleImmutableEntry](https://developer.android.com/reference/java/util/AbstractMap.SimpleImmutableEntry)\<K, V\> | An unmodifiable Entry maintaining a key and a value. |
| [AbstractQueue](https://developer.android.com/reference/java/util/AbstractQueue)\<E\> | This class provides skeletal implementations of some `https://developer.android.com/reference/java/util/Queue` operations. |
| [AbstractSequentialList](https://developer.android.com/reference/java/util/AbstractSequentialList)\<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). |
| [AbstractSet](https://developer.android.com/reference/java/util/AbstractSet)\<E\> | This class provides a skeletal implementation of the `Set` interface to minimize the effort required to implement this interface. |
| [ArrayDeque](https://developer.android.com/reference/java/util/ArrayDeque)\<E\> | Resizable-array implementation of the `https://developer.android.com/reference/java/util/Deque` interface. |
| [ArrayList](https://developer.android.com/reference/java/util/ArrayList)\<E\> | Resizable-array implementation of the `List` interface. |
| [Arrays](https://developer.android.com/reference/java/util/Arrays) | This class contains various methods for manipulating arrays (such as sorting and searching). |
| [Base64](https://developer.android.com/reference/java/util/Base64) | This class consists exclusively of static methods for obtaining encoders and decoders for the Base64 encoding scheme. |
| [Base64.Decoder](https://developer.android.com/reference/java/util/Base64.Decoder) | This class implements a decoder for decoding byte data using the Base64 encoding scheme as specified in RFC 4648 and RFC 2045. |
| [Base64.Encoder](https://developer.android.com/reference/java/util/Base64.Encoder) | This class implements an encoder for encoding byte data using the Base64 encoding scheme as specified in RFC 4648 and RFC 2045. |
| [BitSet](https://developer.android.com/reference/java/util/BitSet) | This class implements a vector of bits that grows as needed. |
| [Calendar](https://developer.android.com/reference/java/util/Calendar) | The `Calendar` class is an abstract class that provides methods for converting between a specific instant in time and a set of `https://developer.android.com/reference/java/util/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. |
| [Calendar.Builder](https://developer.android.com/reference/java/util/Calendar.Builder) | `Calendar.Builder` is used for creating a `Calendar` from various date-time parameters. |
| [Collections](https://developer.android.com/reference/java/util/Collections) | This class consists exclusively of static methods that operate on or return collections. |
| [Currency](https://developer.android.com/reference/java/util/Currency) | Represents a currency. |
| [Date](https://developer.android.com/reference/java/util/Date) | The class `Date` represents a specific instant in time, with millisecond precision. |
| [Dictionary](https://developer.android.com/reference/java/util/Dictionary)\<K, V\> | The `Dictionary` class is the abstract parent of any class, such as `Hashtable`, which maps keys to values. |
| [DoubleSummaryStatistics](https://developer.android.com/reference/java/util/DoubleSummaryStatistics) | A state object for collecting statistics such as count, min, max, sum, and average. |
| [EnumMap](https://developer.android.com/reference/java/util/EnumMap)\<K extends [Enum](https://developer.android.com/reference/java/lang/Enum)\<K\>, V\> | A specialized `https://developer.android.com/reference/java/util/Map` implementation for use with enum type keys. |
| [EnumSet](https://developer.android.com/reference/java/util/EnumSet)\<E extends [Enum](https://developer.android.com/reference/java/lang/Enum)\<E\>\> | A specialized `https://developer.android.com/reference/java/util/Set` implementation for use with enum types. |
| [EventListenerProxy](https://developer.android.com/reference/java/util/EventListenerProxy)\<T extends [EventListener](https://developer.android.com/reference/java/util/EventListener)\> | An abstract wrapper class for an `EventListener` class which associates a set of additional parameters with the listener. |
| [EventObject](https://developer.android.com/reference/java/util/EventObject) | The root class from which all event state objects shall be derived. |
| [FormattableFlags](https://developer.android.com/reference/java/util/FormattableFlags) | FormattableFlags are passed to the `https://developer.android.com/reference/java/util/Formattable#formatTo(java.util.Formatter,%20int,%20int,%20int)` method and modify the output format for [Formattables](https://developer.android.com/reference/java/util/Formattable). |
| [Formatter](https://developer.android.com/reference/java/util/Formatter) | An interpreter for printf-style format strings. |
| [GregorianCalendar](https://developer.android.com/reference/java/util/GregorianCalendar) | `GregorianCalendar` is a concrete subclass of `Calendar` and provides the standard calendar system used by most of the world. |
| [HashMap](https://developer.android.com/reference/java/util/HashMap)\<K, V\> | Hash table based implementation of the `Map` interface. |
| [HashSet](https://developer.android.com/reference/java/util/HashSet)\<E\> | This class implements the `Set` interface, backed by a hash table (actually a `HashMap` instance). |
| [Hashtable](https://developer.android.com/reference/java/util/Hashtable)\<K, V\> | This class implements a hash table, which maps keys to values. |
| [HexFormat](https://developer.android.com/reference/java/util/HexFormat) | `HexFormat` converts between bytes and chars and hex-encoded strings which may include additional formatting markup such as prefixes, suffixes, and delimiters. |
| [IdentityHashMap](https://developer.android.com/reference/java/util/IdentityHashMap)\<K, V\> | This class implements the `Map` interface with a hash table, using reference-equality in place of object-equality when comparing keys (and values). |
| [IntSummaryStatistics](https://developer.android.com/reference/java/util/IntSummaryStatistics) | A state object for collecting statistics such as count, min, max, sum, and average. |
| [LinkedHashMap](https://developer.android.com/reference/java/util/LinkedHashMap)\<K, V\> | Hash table and linked list implementation of the `Map` interface, with well-defined encounter order. |
| [LinkedHashSet](https://developer.android.com/reference/java/util/LinkedHashSet)\<E\> | Hash table and linked list implementation of the `Set` interface, with well-defined encounter order. |
| [LinkedList](https://developer.android.com/reference/java/util/LinkedList)\<E\> | Doubly-linked list implementation of the `List` and `Deque` interfaces. |
| [ListResourceBundle](https://developer.android.com/reference/java/util/ListResourceBundle) | `ListResourceBundle` is an abstract subclass of `ResourceBundle` that manages resources for a locale in a convenient and easy to use list. |
| [Locale](https://developer.android.com/reference/java/util/Locale) | A `Locale` object represents a specific geographical, political, or cultural region. |
| [Locale.Builder](https://developer.android.com/reference/java/util/Locale.Builder) | `Builder` is used to build instances of `Locale` from values configured by the setters. |
| [Locale.LanguageRange](https://developer.android.com/reference/java/util/Locale.LanguageRange) | This class expresses a *Language Range* defined in [RFC 4647 Matching of Language Tags](https://tools.ietf.org/html/rfc4647). |
| [LongSummaryStatistics](https://developer.android.com/reference/java/util/LongSummaryStatistics) | A state object for collecting statistics such as count, min, max, sum, and average. |
| [Objects](https://developer.android.com/reference/java/util/Objects) | This class consists of `static` utility methods for operating on objects, or checking certain conditions before operation. |
| [Observable](https://developer.android.com/reference/java/util/Observable) | *This class was deprecated in API level 33. This class and the `https://developer.android.com/reference/java/util/Observer` interface have been deprecated. The event model supported by `Observer` and `Observable` is quite limited, the order of notifications delivered by `Observable` is unspecified, and state changes are not in one-for-one correspondence with notifications. For a richer event model, consider using the `https://developer.android.com/reference/java/beans/package-summary` package. For reliable and ordered messaging among threads, consider using one of the concurrent data structures in the `https://developer.android.com/reference/java/util/concurrent/package-summary` package. For reactive streams style programming, see the `https://developer.android.com/reference/java/util/concurrent/Flow` API.* |
| [Optional](https://developer.android.com/reference/java/util/Optional)\<T\> | A container object which may or may not contain a non-`null` value. |
| [OptionalDouble](https://developer.android.com/reference/java/util/OptionalDouble) | A container object which may or may not contain a `double` value. |
| [OptionalInt](https://developer.android.com/reference/java/util/OptionalInt) | A container object which may or may not contain an `int` value. |
| [OptionalLong](https://developer.android.com/reference/java/util/OptionalLong) | A container object which may or may not contain a `long` value. |
| [PriorityQueue](https://developer.android.com/reference/java/util/PriorityQueue)\<E\> | An unbounded priority [queue](https://developer.android.com/reference/java/util/Queue) based on a priority heap. |
| [Properties](https://developer.android.com/reference/java/util/Properties) | The `Properties` class represents a persistent set of properties. |
| [PropertyPermission](https://developer.android.com/reference/java/util/PropertyPermission) | Legacy security code; do not use. |
| [PropertyResourceBundle](https://developer.android.com/reference/java/util/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](https://developer.android.com/reference/java/util/Random) | An instance of this class is used to generate a stream of pseudorandom numbers; its period is only 2^48^. |
| [ResourceBundle](https://developer.android.com/reference/java/util/ResourceBundle) | Resource bundles contain locale-specific objects. |
| [ResourceBundle.Control](https://developer.android.com/reference/java/util/ResourceBundle.Control) | `ResourceBundle.Control` defines a set of callback methods that are invoked by the `https://developer.android.com/reference/java/util/ResourceBundle#getBundle(java.lang.String,%20java.util.Locale,%20java.lang.ClassLoader,%20java.util.ResourceBundle.Control)` factory methods during the bundle loading process. |
| [Scanner](https://developer.android.com/reference/java/util/Scanner) | A simple text scanner which can parse primitive types and strings using regular expressions. |
| [ServiceLoader](https://developer.android.com/reference/java/util/ServiceLoader)\<S\> | A facility to load implementations of a service. |
| [SimpleTimeZone](https://developer.android.com/reference/java/util/SimpleTimeZone) | `SimpleTimeZone` is a concrete subclass of `TimeZone` that represents a time zone for use with a Gregorian calendar. |
| [Spliterators](https://developer.android.com/reference/java/util/Spliterators) | Static classes and methods for operating on or creating instances of `https://developer.android.com/reference/java/util/Spliterator` and its primitive specializations `https://developer.android.com/reference/java/util/Spliterator.OfInt`, `https://developer.android.com/reference/java/util/Spliterator.OfLong`, and `https://developer.android.com/reference/java/util/Spliterator.OfDouble`. |
| [Spliterators.AbstractDoubleSpliterator](https://developer.android.com/reference/java/util/Spliterators.AbstractDoubleSpliterator) | An abstract `Spliterator.OfDouble` that implements `trySplit` to permit limited parallelism. |
| [Spliterators.AbstractIntSpliterator](https://developer.android.com/reference/java/util/Spliterators.AbstractIntSpliterator) | An abstract `Spliterator.OfInt` that implements `trySplit` to permit limited parallelism. |
| [Spliterators.AbstractLongSpliterator](https://developer.android.com/reference/java/util/Spliterators.AbstractLongSpliterator) | An abstract `Spliterator.OfLong` that implements `trySplit` to permit limited parallelism. |
| [Spliterators.AbstractSpliterator](https://developer.android.com/reference/java/util/Spliterators.AbstractSpliterator)\<T\> | An abstract `Spliterator` that implements `trySplit` to permit limited parallelism. |
| [SplittableRandom](https://developer.android.com/reference/java/util/SplittableRandom) | A generator of uniform pseudorandom values (with period 2^64^) applicable for use in (among other contexts) isolated parallel computations that may generate subtasks. |
| [Stack](https://developer.android.com/reference/java/util/Stack)\<E\> | The `Stack` class represents a last-in-first-out (LIFO) stack of objects. |
| [StringJoiner](https://developer.android.com/reference/java/util/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. |
| [StringTokenizer](https://developer.android.com/reference/java/util/StringTokenizer) | The string tokenizer class allows an application to break a string into tokens. |
| [Timer](https://developer.android.com/reference/java/util/Timer) | A facility for threads to schedule tasks for future execution in a background thread. |
| [TimerTask](https://developer.android.com/reference/java/util/TimerTask) | A task that can be scheduled for one-time or repeated execution by a `https://developer.android.com/reference/java/util/Timer`. |
| [TimeZone](https://developer.android.com/reference/java/util/TimeZone) | `TimeZone` represents a time zone offset, and also figures out daylight savings. |
| [TreeMap](https://developer.android.com/reference/java/util/TreeMap)\<K, V\> | A Red-Black tree based `https://developer.android.com/reference/java/util/NavigableMap` implementation. |
| [TreeSet](https://developer.android.com/reference/java/util/TreeSet)\<E\> | A `https://developer.android.com/reference/java/util/NavigableSet` implementation based on a `https://developer.android.com/reference/java/util/TreeMap`. |
| [UUID](https://developer.android.com/reference/java/util/UUID) | A class that represents an immutable universally unique identifier (UUID). |
| [Vector](https://developer.android.com/reference/java/util/Vector)\<E\> | The `Vector` class implements a growable array of objects. |
| [WeakHashMap](https://developer.android.com/reference/java/util/WeakHashMap)\<K, V\> | Hash table based implementation of the `Map` interface, with *weak keys*. |

## Enums

|---|---|
| [Formatter.BigDecimalLayoutForm](https://developer.android.com/reference/java/util/Formatter.BigDecimalLayoutForm) | Enum for `BigDecimal` formatting. |
| [Locale.Category](https://developer.android.com/reference/java/util/Locale.Category) | Enum for locale categories. |
| [Locale.FilteringMode](https://developer.android.com/reference/java/util/Locale.FilteringMode) | This enum provides constants to select a filtering mode for locale matching. |
| [Locale.IsoCountryCode](https://developer.android.com/reference/java/util/Locale.IsoCountryCode) | Enum for specifying the type defined in ISO 3166. |

## Exceptions

|---|---|
| [ConcurrentModificationException](https://developer.android.com/reference/java/util/ConcurrentModificationException) | This exception may be thrown by methods that have detected concurrent modification of an object when such modification is not permissible. |
| [DuplicateFormatFlagsException](https://developer.android.com/reference/java/util/DuplicateFormatFlagsException) | Unchecked exception thrown when duplicate flags are provided in the format specifier. |
| [EmptyStackException](https://developer.android.com/reference/java/util/EmptyStackException) | Thrown by methods in the `Stack` class to indicate that the stack is empty. |
| [FormatFlagsConversionMismatchException](https://developer.android.com/reference/java/util/FormatFlagsConversionMismatchException) | Unchecked exception thrown when a conversion and flag are incompatible. |
| [FormatterClosedException](https://developer.android.com/reference/java/util/FormatterClosedException) | Unchecked exception thrown when the formatter has been closed. |
| [IllegalFormatCodePointException](https://developer.android.com/reference/java/util/IllegalFormatCodePointException) | Unchecked exception thrown when a character with an invalid Unicode code point as defined by `https://developer.android.com/reference/java/lang/Character#isValidCodePoint(int)` is passed to the `https://developer.android.com/reference/java/util/Formatter`. |
| [IllegalFormatConversionException](https://developer.android.com/reference/java/util/IllegalFormatConversionException) | Unchecked exception thrown when the argument corresponding to the format specifier is of an incompatible type. |
| [IllegalFormatException](https://developer.android.com/reference/java/util/IllegalFormatException) | Unchecked exception thrown when a format string contains an illegal syntax or a format specifier that is incompatible with the given arguments. |
| [IllegalFormatFlagsException](https://developer.android.com/reference/java/util/IllegalFormatFlagsException) | Unchecked exception thrown when an illegal combination flags is given. |
| [IllegalFormatPrecisionException](https://developer.android.com/reference/java/util/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. |
| [IllegalFormatWidthException](https://developer.android.com/reference/java/util/IllegalFormatWidthException) | Unchecked exception thrown when the format width is a negative value other than `-1` or is otherwise unsupported. |
| [IllformedLocaleException](https://developer.android.com/reference/java/util/IllformedLocaleException) | Thrown by methods in `https://developer.android.com/reference/java/util/Locale` and `https://developer.android.com/reference/java/util/Locale.Builder` to indicate that an argument is not a well-formed BCP 47 tag. |
| [InputMismatchException](https://developer.android.com/reference/java/util/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. |
| [InvalidPropertiesFormatException](https://developer.android.com/reference/java/util/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 `https://developer.android.com/reference/java/util/Properties` specification. |
| [MissingFormatArgumentException](https://developer.android.com/reference/java/util/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. |
| [MissingFormatWidthException](https://developer.android.com/reference/java/util/MissingFormatWidthException) | Unchecked exception thrown when the format width is required. |
| [MissingResourceException](https://developer.android.com/reference/java/util/MissingResourceException) | Signals that a resource is missing. |
| [NoSuchElementException](https://developer.android.com/reference/java/util/NoSuchElementException) | Thrown by various accessor methods to indicate that the element being requested does not exist. |
| [TooManyListenersException](https://developer.android.com/reference/java/util/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. |
| [UnknownFormatConversionException](https://developer.android.com/reference/java/util/UnknownFormatConversionException) | Unchecked exception thrown when an unknown conversion is given. |
| [UnknownFormatFlagsException](https://developer.android.com/reference/java/util/UnknownFormatFlagsException) | Unchecked exception thrown when an unknown flag is given. |

## Errors

|---|---|
| [ServiceConfigurationError](https://developer.android.com/reference/java/util/ServiceConfigurationError) | Error thrown when something goes wrong while locating, loading, or instantiating a service provider. |

-

  ## Interfaces

  - [Collection](https://developer.android.com/reference/java/util/Collection)
  - [Comparator](https://developer.android.com/reference/java/util/Comparator)
  - [Deque](https://developer.android.com/reference/java/util/Deque)
  - [Enumeration](https://developer.android.com/reference/java/util/Enumeration)
  - [EventListener](https://developer.android.com/reference/java/util/EventListener)
  - [Formattable](https://developer.android.com/reference/java/util/Formattable)
  - [Iterator](https://developer.android.com/reference/java/util/Iterator)
  - [List](https://developer.android.com/reference/java/util/List)
  - [ListIterator](https://developer.android.com/reference/java/util/ListIterator)
  - [Map](https://developer.android.com/reference/java/util/Map)
  - [Map.Entry](https://developer.android.com/reference/java/util/Map.Entry)
  - [NavigableMap](https://developer.android.com/reference/java/util/NavigableMap)
  - [NavigableSet](https://developer.android.com/reference/java/util/NavigableSet)
  - [Observer](https://developer.android.com/reference/java/util/Observer)
  - [PrimitiveIterator](https://developer.android.com/reference/java/util/PrimitiveIterator)
  - [PrimitiveIterator.OfDouble](https://developer.android.com/reference/java/util/PrimitiveIterator.OfDouble)
  - [PrimitiveIterator.OfInt](https://developer.android.com/reference/java/util/PrimitiveIterator.OfInt)
  - [PrimitiveIterator.OfLong](https://developer.android.com/reference/java/util/PrimitiveIterator.OfLong)
  - [Queue](https://developer.android.com/reference/java/util/Queue)
  - [RandomAccess](https://developer.android.com/reference/java/util/RandomAccess)
  - [SequencedCollection](https://developer.android.com/reference/java/util/SequencedCollection)
  - [SequencedMap](https://developer.android.com/reference/java/util/SequencedMap)
  - [SequencedSet](https://developer.android.com/reference/java/util/SequencedSet)
  - [ServiceLoader.Provider](https://developer.android.com/reference/java/util/ServiceLoader.Provider)
  - [Set](https://developer.android.com/reference/java/util/Set)
  - [SortedMap](https://developer.android.com/reference/java/util/SortedMap)
  - [SortedSet](https://developer.android.com/reference/java/util/SortedSet)
  - [Spliterator](https://developer.android.com/reference/java/util/Spliterator)
  - [Spliterator.OfDouble](https://developer.android.com/reference/java/util/Spliterator.OfDouble)
  - [Spliterator.OfInt](https://developer.android.com/reference/java/util/Spliterator.OfInt)
  - [Spliterator.OfLong](https://developer.android.com/reference/java/util/Spliterator.OfLong)
  - [Spliterator.OfPrimitive](https://developer.android.com/reference/java/util/Spliterator.OfPrimitive)
-

  ## Classes

  - [AbstractCollection](https://developer.android.com/reference/java/util/AbstractCollection)
  - [AbstractList](https://developer.android.com/reference/java/util/AbstractList)
  - [AbstractMap](https://developer.android.com/reference/java/util/AbstractMap)
  - [AbstractMap.SimpleEntry](https://developer.android.com/reference/java/util/AbstractMap.SimpleEntry)
  - [AbstractMap.SimpleImmutableEntry](https://developer.android.com/reference/java/util/AbstractMap.SimpleImmutableEntry)
  - [AbstractQueue](https://developer.android.com/reference/java/util/AbstractQueue)
  - [AbstractSequentialList](https://developer.android.com/reference/java/util/AbstractSequentialList)
  - [AbstractSet](https://developer.android.com/reference/java/util/AbstractSet)
  - [ArrayDeque](https://developer.android.com/reference/java/util/ArrayDeque)
  - [ArrayList](https://developer.android.com/reference/java/util/ArrayList)
  - [Arrays](https://developer.android.com/reference/java/util/Arrays)
  - [Base64](https://developer.android.com/reference/java/util/Base64)
  - [Base64.Decoder](https://developer.android.com/reference/java/util/Base64.Decoder)
  - [Base64.Encoder](https://developer.android.com/reference/java/util/Base64.Encoder)
  - [BitSet](https://developer.android.com/reference/java/util/BitSet)
  - [Calendar](https://developer.android.com/reference/java/util/Calendar)
  - [Calendar.Builder](https://developer.android.com/reference/java/util/Calendar.Builder)
  - [Collections](https://developer.android.com/reference/java/util/Collections)
  - [Currency](https://developer.android.com/reference/java/util/Currency)
  - [Date](https://developer.android.com/reference/java/util/Date)
  - [Dictionary](https://developer.android.com/reference/java/util/Dictionary)
  - [DoubleSummaryStatistics](https://developer.android.com/reference/java/util/DoubleSummaryStatistics)
  - [EnumMap](https://developer.android.com/reference/java/util/EnumMap)
  - [EnumSet](https://developer.android.com/reference/java/util/EnumSet)
  - [EventListenerProxy](https://developer.android.com/reference/java/util/EventListenerProxy)
  - [EventObject](https://developer.android.com/reference/java/util/EventObject)
  - [FormattableFlags](https://developer.android.com/reference/java/util/FormattableFlags)
  - [Formatter](https://developer.android.com/reference/java/util/Formatter)
  - [GregorianCalendar](https://developer.android.com/reference/java/util/GregorianCalendar)
  - [HashMap](https://developer.android.com/reference/java/util/HashMap)
  - [HashSet](https://developer.android.com/reference/java/util/HashSet)
  - [Hashtable](https://developer.android.com/reference/java/util/Hashtable)
  - [HexFormat](https://developer.android.com/reference/java/util/HexFormat)
  - [IdentityHashMap](https://developer.android.com/reference/java/util/IdentityHashMap)
  - [IntSummaryStatistics](https://developer.android.com/reference/java/util/IntSummaryStatistics)
  - [LinkedHashMap](https://developer.android.com/reference/java/util/LinkedHashMap)
  - [LinkedHashSet](https://developer.android.com/reference/java/util/LinkedHashSet)
  - [LinkedList](https://developer.android.com/reference/java/util/LinkedList)
  - [ListResourceBundle](https://developer.android.com/reference/java/util/ListResourceBundle)
  - [Locale](https://developer.android.com/reference/java/util/Locale)
  - [Locale.Builder](https://developer.android.com/reference/java/util/Locale.Builder)
  - [Locale.LanguageRange](https://developer.android.com/reference/java/util/Locale.LanguageRange)
  - [LongSummaryStatistics](https://developer.android.com/reference/java/util/LongSummaryStatistics)
  - [Objects](https://developer.android.com/reference/java/util/Objects)
  - [Observable](https://developer.android.com/reference/java/util/Observable)
  - [Optional](https://developer.android.com/reference/java/util/Optional)
  - [OptionalDouble](https://developer.android.com/reference/java/util/OptionalDouble)
  - [OptionalInt](https://developer.android.com/reference/java/util/OptionalInt)
  - [OptionalLong](https://developer.android.com/reference/java/util/OptionalLong)
  - [PriorityQueue](https://developer.android.com/reference/java/util/PriorityQueue)
  - [Properties](https://developer.android.com/reference/java/util/Properties)
  - [PropertyPermission](https://developer.android.com/reference/java/util/PropertyPermission)
  - [PropertyResourceBundle](https://developer.android.com/reference/java/util/PropertyResourceBundle)
  - [Random](https://developer.android.com/reference/java/util/Random)
  - [ResourceBundle](https://developer.android.com/reference/java/util/ResourceBundle)
  - [ResourceBundle.Control](https://developer.android.com/reference/java/util/ResourceBundle.Control)
  - [Scanner](https://developer.android.com/reference/java/util/Scanner)
  - [ServiceLoader](https://developer.android.com/reference/java/util/ServiceLoader)
  - [SimpleTimeZone](https://developer.android.com/reference/java/util/SimpleTimeZone)
  - [Spliterators](https://developer.android.com/reference/java/util/Spliterators)
  - [Spliterators.AbstractDoubleSpliterator](https://developer.android.com/reference/java/util/Spliterators.AbstractDoubleSpliterator)
  - [Spliterators.AbstractIntSpliterator](https://developer.android.com/reference/java/util/Spliterators.AbstractIntSpliterator)
  - [Spliterators.AbstractLongSpliterator](https://developer.android.com/reference/java/util/Spliterators.AbstractLongSpliterator)
  - [Spliterators.AbstractSpliterator](https://developer.android.com/reference/java/util/Spliterators.AbstractSpliterator)
  - [SplittableRandom](https://developer.android.com/reference/java/util/SplittableRandom)
  - [Stack](https://developer.android.com/reference/java/util/Stack)
  - [StringJoiner](https://developer.android.com/reference/java/util/StringJoiner)
  - [StringTokenizer](https://developer.android.com/reference/java/util/StringTokenizer)
  - [Timer](https://developer.android.com/reference/java/util/Timer)
  - [TimerTask](https://developer.android.com/reference/java/util/TimerTask)
  - [TimeZone](https://developer.android.com/reference/java/util/TimeZone)
  - [TreeMap](https://developer.android.com/reference/java/util/TreeMap)
  - [TreeSet](https://developer.android.com/reference/java/util/TreeSet)
  - [UUID](https://developer.android.com/reference/java/util/UUID)
  - [Vector](https://developer.android.com/reference/java/util/Vector)
  - [WeakHashMap](https://developer.android.com/reference/java/util/WeakHashMap)
-

  ## Enums

  - [Formatter.BigDecimalLayoutForm](https://developer.android.com/reference/java/util/Formatter.BigDecimalLayoutForm)
  - [Locale.Category](https://developer.android.com/reference/java/util/Locale.Category)
  - [Locale.FilteringMode](https://developer.android.com/reference/java/util/Locale.FilteringMode)
  - [Locale.IsoCountryCode](https://developer.android.com/reference/java/util/Locale.IsoCountryCode)
-

  ## Exceptions

  - [ConcurrentModificationException](https://developer.android.com/reference/java/util/ConcurrentModificationException)
  - [DuplicateFormatFlagsException](https://developer.android.com/reference/java/util/DuplicateFormatFlagsException)
  - [EmptyStackException](https://developer.android.com/reference/java/util/EmptyStackException)
  - [FormatFlagsConversionMismatchException](https://developer.android.com/reference/java/util/FormatFlagsConversionMismatchException)
  - [FormatterClosedException](https://developer.android.com/reference/java/util/FormatterClosedException)
  - [IllegalFormatCodePointException](https://developer.android.com/reference/java/util/IllegalFormatCodePointException)
  - [IllegalFormatConversionException](https://developer.android.com/reference/java/util/IllegalFormatConversionException)
  - [IllegalFormatException](https://developer.android.com/reference/java/util/IllegalFormatException)
  - [IllegalFormatFlagsException](https://developer.android.com/reference/java/util/IllegalFormatFlagsException)
  - [IllegalFormatPrecisionException](https://developer.android.com/reference/java/util/IllegalFormatPrecisionException)
  - [IllegalFormatWidthException](https://developer.android.com/reference/java/util/IllegalFormatWidthException)
  - [IllformedLocaleException](https://developer.android.com/reference/java/util/IllformedLocaleException)
  - [InputMismatchException](https://developer.android.com/reference/java/util/InputMismatchException)
  - [InvalidPropertiesFormatException](https://developer.android.com/reference/java/util/InvalidPropertiesFormatException)
  - [MissingFormatArgumentException](https://developer.android.com/reference/java/util/MissingFormatArgumentException)
  - [MissingFormatWidthException](https://developer.android.com/reference/java/util/MissingFormatWidthException)
  - [MissingResourceException](https://developer.android.com/reference/java/util/MissingResourceException)
  - [NoSuchElementException](https://developer.android.com/reference/java/util/NoSuchElementException)
  - [TooManyListenersException](https://developer.android.com/reference/java/util/TooManyListenersException)
  - [UnknownFormatConversionException](https://developer.android.com/reference/java/util/UnknownFormatConversionException)
  - [UnknownFormatFlagsException](https://developer.android.com/reference/java/util/UnknownFormatFlagsException)
-

  ## Errors

  - [ServiceConfigurationError](https://developer.android.com/reference/java/util/ServiceConfigurationError)