@NonNullByDefault

Package java.util

Contains utility classes including the collections framework and date manipulation.

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.
EventListener	A tagging interface that all event listener interfaces must extend.
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 SortedMap extended with navigation methods returning the closest matches for given search targets.
NavigableSet<E>	A SortedSet extended with navigation methods reporting closest matches for given search targets.
Observer	A class can implement the Observer interface when it wants to be informed of changes in observable objects.
Queue<E>	A collection designed for holding elements prior to processing.
RandomAccess	Marker interface used by List implementations to indicate that they support fast (generally constant time) random access.
Set<E>	A collection that contains no duplicate elements.
SortedMap<K,V>	A Map that further provides a total ordering on its keys.
SortedSet<E>	A Set that further provides a total ordering on its elements.

Class Summary

Class	Description
AbstractCollection<E>	This class provides a skeletal implementation of the Collection interface, to minimize the effort required to implement this interface.
AbstractList<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).
AbstractMap<K,V>	This class provides a skeletal implementation of the Map interface, 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 Queue operations.
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<E>	This class provides a skeletal implementation of the Set interface to minimize the effort required to implement this interface.
ArrayDeque<E>	Resizable-array implementation of the Deque interface.
ArrayList<E>	Resizable-array implementation of the List interface.
Arrays	This class contains various methods for manipulating arrays (such as sorting and searching).
Base64	This class consists exclusively of static methods for obtaining encoders and decoders for the Base64 encoding scheme.
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	This class implements an encoder for encoding byte data using the Base64 encoding scheme as specified in RFC 4648 and RFC 2045.
BitSet	This class implements a vector of bits that grows as needed.
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.
Collections	This class consists exclusively of static methods that operate on or return collections.
Date	The class Date represents a specific instant in time, with millisecond precision.
Dictionary<K,V>	The Dictionary class is the abstract parent of any class, such as Hashtable, which maps keys to values.
EventObject	The root class from which all event state objects shall be derived.
Formatter	An interpreter for printf-style format strings.
HashMap<K,V>	Hash table based implementation of the Map interface.
HashSet<E>	This class implements the Set interface, backed by a hash table (actually a HashMap instance).
Hashtable<K,V>	This class implements a hash table, which maps keys to values.
LinkedList<E>	Doubly-linked list implementation of the List and Deque interfaces.
Objects	This class consists of static utility methods for operating on objects.
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.
Random	An instance of this class is used to generate a stream of pseudorandom numbers.
Stack<E>	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.
TimeZone	TimeZone represents a time zone offset, and also figures out daylight savings.
TreeMap<K,V>	A Red-Black tree based NavigableMap implementation.
TreeSet<E>	A NavigableSet implementation based on a TreeMap.
Vector<E>	The Vector class implements a growable array of objects.
WeakHashMap<K,V>	Hash table based implementation of the Map interface, with weak keys.

Exception Summary

Exception	Description
ConcurrentModificationException	This exception may be thrown by methods that have detected concurrent modification of an object when such modification is not permissible.
DuplicateFormatFlagsException	Unchecked exception thrown when duplicate flags are provided in the format specifier.
EmptyStackException	Thrown by methods in the Stack class to indicate that the stack is empty.
FormatFlagsConversionMismatchException	Unchecked exception thrown when a conversion and flag are incompatible.
FormatterClosedException	Unchecked exception thrown when the formatter has been closed.
IllegalFormatConversionException	Unchecked exception thrown when the argument corresponding to the format specifier is of an incompatible type.
IllegalFormatException	Unchecked exception thrown when a format string contains an illegal syntax or a format specifier that is incompatible with the given arguments.
IllegalFormatFlagsException	Unchecked exception thrown when an illegal combination flags is given.
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	Unchecked exception thrown when the format width is a negative value other than -1 or is otherwise unsupported.
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	Unchecked exception thrown when the format width is required.
NoSuchElementException	Thrown by the nextElement method of an Enumeration to indicate that there are no more elements in the enumeration.
UnknownFormatConversionException	Unchecked exception thrown when an unknown conversion is given.
UnknownFormatFlagsException	Unchecked exception thrown when an unknown flag is given.