Uses of Interface
java.util.Map

Packages that use Map

Package	Description
java.lang
java.net
java.text
java.util
java.util.concurrent	Utility classes commonly useful in concurrent programming.
java.util.stream	Classes to support functional-style operations on streams of elements, such as map-reduce transformations on collections.

Uses of Map in java.lang

Methods in java.lang that return Map

Modifier and Type	Method and Description
static Map<Thread,StackTraceElement[]>	Thread.getAllStackTraces() Returns a map of stack traces for all live threads.

Uses of Map in java.net

Methods in java.net that return Map

Modifier and Type	Method and Description
Map<String,List<String>>	URLConnection.getHeaderFields() Returns an unmodifiable Map of the header fields.
Map<String,List<String>>	URLConnection.getRequestProperties() Returns an unmodifiable Map of general request properties for this connection.

Uses of Map in java.text

Methods in java.text that return Map

Modifier and Type	Method and Description
Map<AttributedCharacterIterator.Attribute,Object>	AttributedCharacterIterator.getAttributes() Returns a map with the attributes defined on the current character.

Methods in java.text with parameters of type Map

Modifier and Type	Method and Description
void	AttributedString.addAttributes(Map<? extends AttributedCharacterIterator.Attribute,?> attributes, int beginIndex, int endIndex) Adds a set of attributes to a subrange of the string.

Constructors in java.text with parameters of type Map

Constructor and Description
AttributedString(String text, Map<? extends AttributedCharacterIterator.Attribute,?> attributes) Constructs an AttributedString instance with the given text and attributes.

Uses of Map in java.util

Subinterfaces of Map in java.util

Modifier and Type	Interface and Description
interface	NavigableMap<K,V> A SortedMap extended with navigation methods returning the closest matches for given search targets.
interface	SortedMap<K,V> A Map that further provides a total ordering on its keys.

Classes in java.util that implement Map

Modifier and Type	Class and Description
class	AbstractMap<K,V> This class provides a skeletal implementation of the Map interface, to minimize the effort required to implement this interface.
class	EnumMap<K extends Enum<K>,V> A specialized Map implementation for use with enum type keys.
class	HashMap<K,V> Hash table based implementation of the Map interface.
class	Hashtable<K,V> This class implements a hash table, which maps keys to values.
class	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).
class	LinkedHashMap<K,V> Hash table and linked list implementation of the Map interface, with predictable iteration order.
class	Properties The Properties class represents a persistent set of properties.
class	TreeMap<K,V> A Red-Black tree based NavigableMap implementation.
class	WeakHashMap<K,V> Hash table based implementation of the Map interface, with weak keys.

Fields in java.util declared as Map

Modifier and Type	Field and Description
static Map	Collections.EMPTY_MAP The empty map (immutable).

Methods in java.util that return Map

Modifier and Type	Method and Description
static <K,V> Map<K,V>	Collections.checkedMap(Map<K,V> m, Class<K> keyType, Class<V> valueType) Returns a dynamically typesafe view of the specified map.
static <K,V> Map<K,V>	Collections.emptyMap() Returns the empty map (immutable).
Map<String,Integer>	Calendar.getDisplayNames(int field, int style, Locale locale) Returns a Map containing all names of the calendar field in the given style and locale and their corresponding field values.
static <K,V> Map<K,V>	Collections.singletonMap(K key, V value) Returns an immutable map, mapping only the specified key to the specified value.
static <K,V> Map<K,V>	Collections.synchronizedMap(Map<K,V> m) Returns a synchronized (thread-safe) map backed by the specified map.
static <K,V> Map<K,V>	Collections.unmodifiableMap(Map<? extends K,? extends V> m) Returns an unmodifiable view of the specified map.

Methods in java.util with parameters of type Map

Modifier and Type	Method and Description
static <K,V> Map<K,V>	Collections.checkedMap(Map<K,V> m, Class<K> keyType, Class<V> valueType) Returns a dynamically typesafe view of the specified map.
static <E> Set<E>	Collections.newSetFromMap(Map<E,Boolean> map) Returns a set backed by the specified map.
void	WeakHashMap.putAll(Map<? extends K,? extends V> m) Copies all of the mappings from the specified map to this map.
void	TreeMap.putAll(Map<? extends K,? extends V> map) Copies all of the mappings from the specified map to this map.
void	Map.putAll(Map<? extends K,? extends V> m) Copies all of the mappings from the specified map to this map (optional operation).
void	IdentityHashMap.putAll(Map<? extends K,? extends V> m) Copies all of the mappings from the specified map to this map.
void	Hashtable.putAll(Map<? extends K,? extends V> t) Copies all of the mappings from the specified map to this hashtable.
void	HashMap.putAll(Map<? extends K,? extends V> m) Copies all of the mappings from the specified map to this map.
void	EnumMap.putAll(Map<? extends K,? extends V> m) Copies all of the mappings from the specified map to this map.
void	AbstractMap.putAll(Map<? extends K,? extends V> m) Copies all of the mappings from the specified map to this map (optional operation).
static <K,V> Map<K,V>	Collections.synchronizedMap(Map<K,V> m) Returns a synchronized (thread-safe) map backed by the specified map.
static <K,V> Map<K,V>	Collections.unmodifiableMap(Map<? extends K,? extends V> m) Returns an unmodifiable view of the specified map.

Constructors in java.util with parameters of type Map

Constructor and Description
EnumMap(Map<K,? extends V> m) Creates an enum map initialized from the specified map.
HashMap(Map<? extends K,? extends V> m) Constructs a new HashMap with the same mappings as the specified Map.
Hashtable(Map<? extends K,? extends V> t) Constructs a new hashtable with the same mappings as the given Map.
IdentityHashMap(Map<? extends K,? extends V> m) Constructs a new identity hash map containing the keys-value mappings in the specified map.
LinkedHashMap(Map<? extends K,? extends V> m) Constructs an insertion-ordered LinkedHashMap instance with the same mappings as the specified map.
TreeMap(Map<? extends K,? extends V> m) Constructs a new tree map containing the same mappings as the given map, ordered according to the natural ordering of its keys.
WeakHashMap(Map<? extends K,? extends V> m) Constructs a new WeakHashMap with the same mappings as the specified map.

Uses of Map in java.util.concurrent

Subinterfaces of Map in java.util.concurrent

Modifier and Type	Interface and Description
interface	ConcurrentMap<K,V> A Map providing additional atomic putIfAbsent, remove, and replace methods.
interface	ConcurrentNavigableMap<K,V> A ConcurrentMap supporting NavigableMap operations, and recursively so for its navigable sub-maps.

Classes in java.util.concurrent that implement Map

Modifier and Type	Class and Description
class	ConcurrentHashMap<K,V> A hash table supporting full concurrency of retrievals and adjustable expected concurrency for updates.
class	ConcurrentSkipListMap<K,V> A scalable concurrent ConcurrentNavigableMap implementation.

Methods in java.util.concurrent with parameters of type Map

Modifier and Type	Method and Description
void	ConcurrentHashMap.putAll(Map<? extends K,? extends V> m)

Constructors in java.util.concurrent with parameters of type Map

Constructor and Description
ConcurrentHashMap(Map<? extends K,? extends V> m) Creates a new map with the same mappings as the given map.
ConcurrentSkipListMap(Map<? extends K,? extends V> m) Constructs a new map containing the same mappings as the given map, sorted according to the natural ordering of the keys.

Uses of Map in java.util.stream

Methods in java.util.stream with type parameters of type Map

Modifier and Type	Method and Description
static <T,K,D,A,M extends Map<K,D>> Collector<T,?,M>	Collectors.groupingBy(Function<? super T,? extends K> classifier, Supplier<M> mapFactory, Collector<? super T,A,D> downstream) Returns a Collector implementing a cascaded "group by" operation on input elements of type T, grouping elements according to a classification function, and then performing a reduction operation on the values associated with a given key using the specified downstream Collector.
static <T,K,U,M extends Map<K,U>> Collector<T,?,M>	Collectors.toMap(Function<? super T,? extends K> keyMapper, Function<? super T,? extends U> valueMapper, BinaryOperator<U> mergeFunction, Supplier<M> mapSupplier) Returns a Collector that accumulates elements into a Map whose keys and values are the result of applying the provided mapping functions to the input elements.

Methods in java.util.stream that return types with arguments of type Map

Modifier and Type	Method and Description
static <T,K> Collector<T,?,Map<K,List<T>>>	Collectors.groupingBy(Function<? super T,? extends K> classifier) Returns a Collector implementing a "group by" operation on input elements of type T, grouping elements according to a classification function, and returning the results in a Map.
static <T,K,A,D> Collector<T,?,Map<K,D>>	Collectors.groupingBy(Function<? super T,? extends K> classifier, Collector<? super T,A,D> downstream) Returns a Collector implementing a cascaded "group by" operation on input elements of type T, grouping elements according to a classification function, and then performing a reduction operation on the values associated with a given key using the specified downstream Collector.
static <T> Collector<T,?,Map<Boolean,List<T>>>	Collectors.partitioningBy(Predicate<? super T> predicate) Returns a Collector which partitions the input elements according to a Predicate, and organizes them into a Map<Boolean, List<T>>.
static <T,D,A> Collector<T,?,Map<Boolean,D>>	Collectors.partitioningBy(Predicate<? super T> predicate, Collector<? super T,A,D> downstream) Returns a Collector which partitions the input elements according to a Predicate, reduces the values in each partition according to another Collector, and organizes them into a Map<Boolean, D> whose values are the result of the downstream reduction.
static <T,K,U> Collector<T,?,Map<K,U>>	Collectors.toMap(Function<? super T,? extends K> keyMapper, Function<? super T,? extends U> valueMapper) Returns a Collector that accumulates elements into a Map whose keys and values are the result of applying the provided mapping functions to the input elements.
static <T,K,U> Collector<T,?,Map<K,U>>	Collectors.toMap(Function<? super T,? extends K> keyMapper, Function<? super T,? extends U> valueMapper, BinaryOperator<U> mergeFunction) Returns a Collector that accumulates elements into a Map whose keys and values are the result of applying the provided mapping functions to the input elements.