Interface ConcurrentNavigableMap<K,V>

Type Parameters:: K - the type of keys maintained by this map; V - the type of mapped values

All Superinterfaces:: ConcurrentMap<K,V>, Map<K,V>, NavigableMap<K,V>, SequencedMap<K,V>, SortedMap<K,V>

All Known Implementing Classes:: ConcurrentSkipListMap

public interface ConcurrentNavigableMap<K,V> extends ConcurrentMap<K,V>, NavigableMap<K,V>

A ConcurrentMap supporting NavigableMap operations, and recursively so for its navigable sub-maps.

This interface is a member of the Java Collections Framework.

Since:: 1.6

Nested Class Summary

Nested classes/interfaces declared in interface Map

Map.Entry<K,V>

Modifier and Type	Interface	Description
`static interface`	`Map.Entry<K,V>`	A map entry (key-value pair).

Method Summary

Modifier and Type	Method	Description
`NavigableSet<K>`	`descendingKeySet()`	Returns a reverse order `NavigableSet` view of the keys contained in this map.
`ConcurrentNavigableMap<K,V>`	`descendingMap()`	Returns a reverse order view of the mappings contained in this map.
`ConcurrentNavigableMap<K,V>`	`headMap(K toKey)`	Returns a view of the portion of this map whose keys are strictly less than `toKey`.
`ConcurrentNavigableMap<K,V>`	`headMap(K toKey, boolean inclusive)`	Returns a view of the portion of this map whose keys are less than (or equal to, if `inclusive` is true) `toKey`.
`NavigableSet<K>`	`keySet()`	Returns a `NavigableSet` view of the keys contained in this map.
`NavigableSet<K>`	`navigableKeySet()`	Returns a `NavigableSet` view of the keys contained in this map.
`ConcurrentNavigableMap<K,V>`	`subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive)`	Returns a view of the portion of this map whose keys range from `fromKey` to `toKey`.
`ConcurrentNavigableMap<K,V>`	`subMap(K fromKey, K toKey)`	Returns a view of the portion of this map whose keys range from `fromKey`, inclusive, to `toKey`, exclusive.
`ConcurrentNavigableMap<K,V>`	`tailMap(K fromKey)`	Returns a view of the portion of this map whose keys are greater than or equal to `fromKey`.
`ConcurrentNavigableMap<K,V>`	`tailMap(K fromKey, boolean inclusive)`	Returns a view of the portion of this map whose keys are greater than (or equal to, if `inclusive` is true) `fromKey`.

Methods declared in interface ConcurrentMap

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

Modifier and Type	Method	Description
`default V`	`compute(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction)`	Attempts to compute a mapping for the specified key and its current mapped value, or `null` if there is no current mapping (optional operation).
`default V`	`computeIfAbsent(K key, Function<? super K, ? extends V> mappingFunction)`	If the specified key is not already associated with a value (or is mapped to `null`), attempts to compute its value using the given mapping function and enters it into this map unless `null` (optional operation).
`default V`	`computeIfPresent(K key, BiFunction<? super K, ? super V, ? extends V> remappingFunction)`	If the value for the specified key is present and non-null, attempts to compute a new mapping given the key and its current mapped value (optional operation).
`default void`	`forEach(BiConsumer<? super K, ? super V> action)`	Performs the given action for each entry in this map until all entries have been processed or the action throws an exception.
`default V`	`getOrDefault(Object key, V defaultValue)`	Returns the value to which the specified key is mapped, or `defaultValue` if this map contains no mapping for the key.
`default V`	`merge(K key, V value, BiFunction<? super V, ? super V, ? extends V> remappingFunction)`	If the specified key is not already associated with a value or is associated with null, associates it with the given non-null value (optional operation).
`V`	`putIfAbsent(K key, V value)`	If the specified key is not already associated with a value, associates it with the given value.
`boolean`	`remove(Object key, Object value)`	Removes the entry for a key only if currently mapped to a given value.
`V`	`replace(K key, V value)`	Replaces the entry for a key only if currently mapped to some value.
`boolean`	`replace(K key, V oldValue, V newValue)`	Replaces the entry for a key only if currently mapped to a given value.
`default void`	`replaceAll(BiFunction<? super K, ? super V, ? extends V> function)`	Replaces each entry's value with the result of invoking the given function on that entry until all entries have been processed or the function throws an exception (optional operation).

Methods declared in interface Map

clear, containsKey, containsValue, equals, get, hashCode, isEmpty, put, putAll, remove, size

Modifier and Type	Method	Description
`void`	`clear()`	Removes all of the mappings from this map (optional operation).
`boolean`	`containsKey(Object key)`	Returns `true` if this map contains a mapping for the specified key.
`boolean`	`containsValue(Object value)`	Returns `true` if this map maps one or more keys to the specified value.
`boolean`	`equals(Object o)`	Compares the specified object with this map for equality.
`V`	`get(Object key)`	Returns the value to which the specified key is mapped, or `null` if this map contains no mapping for the key.
`int`	`hashCode()`	Returns the hash code value for this map.
`boolean`	`isEmpty()`	Returns `true` if this map contains no key-value mappings.
`V`	`put(K key, V value)`	Associates the specified value with the specified key in this map (optional operation).
`void`	`putAll(Map<? extends K, ? extends V> m)`	Copies all of the mappings from the specified map to this map (optional operation).
`V`	`remove(Object key)`	Removes the mapping for a key from this map if it is present (optional operation).
`int`	`size()`	Returns the number of key-value mappings in this map.

Methods declared in interface NavigableMap

ceilingEntry, ceilingKey, firstEntry, floorEntry, floorKey, higherEntry, higherKey, lastEntry, lowerEntry, lowerKey, pollFirstEntry, pollLastEntry, reversed

Modifier and Type	Method	Description
`Map.Entry<K,V>`	`ceilingEntry(K key)`	Returns a key-value mapping associated with the least key greater than or equal to the given key, or `null` if there is no such key.
`K`	`ceilingKey(K key)`	Returns the least key greater than or equal to the given key, or `null` if there is no such key.
`Map.Entry<K,V>`	`firstEntry()`	Returns a key-value mapping associated with the least key in this map, or `null` if the map is empty.
`Map.Entry<K,V>`	`floorEntry(K key)`	Returns a key-value mapping associated with the greatest key less than or equal to the given key, or `null` if there is no such key.
`K`	`floorKey(K key)`	Returns the greatest key less than or equal to the given key, or `null` if there is no such key.
`Map.Entry<K,V>`	`higherEntry(K key)`	Returns a key-value mapping associated with the least key strictly greater than the given key, or `null` if there is no such key.
`K`	`higherKey(K key)`	Returns the least key strictly greater than the given key, or `null` if there is no such key.
`Map.Entry<K,V>`	`lastEntry()`	Returns a key-value mapping associated with the greatest key in this map, or `null` if the map is empty.
`Map.Entry<K,V>`	`lowerEntry(K key)`	Returns a key-value mapping associated with the greatest key strictly less than the given key, or `null` if there is no such key.
`K`	`lowerKey(K key)`	Returns the greatest key strictly less than the given key, or `null` if there is no such key.
`Map.Entry<K,V>`	`pollFirstEntry()`	Removes and returns a key-value mapping associated with the least key in this map, or `null` if the map is empty (optional operation).
`Map.Entry<K,V>`	`pollLastEntry()`	Removes and returns a key-value mapping associated with the greatest key in this map, or `null` if the map is empty (optional operation).
`default NavigableMap<K,V>`	`reversed()`	Returns a reverse-ordered view of this map.

Methods declared in interface SequencedMap

sequencedEntrySet, sequencedKeySet, sequencedValues

Modifier and Type	Method	Description
`default SequencedSet<Map.Entry<K,V>>`	`sequencedEntrySet()`	Returns a `SequencedSet` view of this map's `entrySet`.
`default SequencedSet<K>`	`sequencedKeySet()`	Returns a `SequencedSet` view of this map's `keySet`.
`default SequencedCollection<V>`	`sequencedValues()`	Returns a `SequencedCollection` view of this map's `values` collection.

Methods declared in interface SortedMap

comparator, entrySet, firstKey, lastKey, putFirst, putLast, values

Modifier and Type	Method	Description
`Comparator<? super K>`	`comparator()`	Returns the comparator used to order the keys in this map, or `null` if this map uses the natural ordering of its keys.
`Set<Map.Entry<K,V>>`	`entrySet()`	Returns a `Set` view of the mappings contained in this map.
`K`	`firstKey()`	Returns the first (lowest) key currently in this map.
`K`	`lastKey()`	Returns the last (highest) key currently in this map.
`default V`	`putFirst(K k, V v)`	Throws `UnsupportedOperationException`.
`default V`	`putLast(K k, V v)`	Throws `UnsupportedOperationException`.
`Collection<V>`	`values()`	Returns a `Collection` view of the values contained in this map.

Method Details

subMap

ConcurrentNavigableMap<K,V> subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive)

Description copied from interface: NavigableMap

Returns a view of the portion of this map whose keys range from fromKey to toKey. If fromKey and toKey are equal, the returned map is empty unless fromInclusive and toInclusive are both true. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports.

The returned map will throw an IllegalArgumentException on an attempt to insert a key outside of its range, or to construct a submap either of whose endpoints lie outside its range.

Specified by:: subMap in interface NavigableMap<K,V>
Parameters:: fromKey - low endpoint of the keys in the returned map; fromInclusive - true if the low endpoint is to be included in the returned view; toKey - high endpoint of the keys in the returned map; toInclusive - true if the high endpoint is to be included in the returned view
Returns:: a view of the portion of this map whose keys range from fromKey to toKey
Throws:: ClassCastException - if fromKey and toKey cannot be compared to one another using this map's comparator (or, if the map has no comparator, using natural ordering). Implementations may, but are not required to, throw this exception if fromKey or toKey cannot be compared to keys currently in the map.; NullPointerException - if fromKey or toKey is null and this map does not permit null keys; IllegalArgumentException - if fromKey is greater than toKey; or if this map itself has a restricted range, and fromKey or toKey lies outside the bounds of the range

headMap

ConcurrentNavigableMap<K,V> headMap(K toKey, boolean inclusive)

Description copied from interface: NavigableMap

Returns a view of the portion of this map whose keys are less than (or equal to, if inclusive is true) toKey. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports.

The returned map will throw an IllegalArgumentException on an attempt to insert a key outside its range.

Specified by:: headMap in interface NavigableMap<K,V>
Parameters:: toKey - high endpoint of the keys in the returned map; inclusive - true if the high endpoint is to be included in the returned view
Returns:: a view of the portion of this map whose keys are less than (or equal to, if inclusive is true) toKey
Throws:: ClassCastException - if toKey is not compatible with this map's comparator (or, if the map has no comparator, if toKey does not implement Comparable). Implementations may, but are not required to, throw this exception if toKey cannot be compared to keys currently in the map.; NullPointerException - if toKey is null and this map does not permit null keys; IllegalArgumentException - if this map itself has a restricted range, and toKey lies outside the bounds of the range

tailMap

ConcurrentNavigableMap<K,V> tailMap(K fromKey, boolean inclusive)

Description copied from interface: NavigableMap

Returns a view of the portion of this map whose keys are greater than (or equal to, if inclusive is true) fromKey. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports.

The returned map will throw an IllegalArgumentException on an attempt to insert a key outside its range.

Specified by:: tailMap in interface NavigableMap<K,V>
Parameters:: fromKey - low endpoint of the keys in the returned map; inclusive - true if the low endpoint is to be included in the returned view
Returns:: a view of the portion of this map whose keys are greater than (or equal to, if inclusive is true) fromKey
Throws:: ClassCastException - if fromKey is not compatible with this map's comparator (or, if the map has no comparator, if fromKey does not implement Comparable). Implementations may, but are not required to, throw this exception if fromKey cannot be compared to keys currently in the map.; NullPointerException - if fromKey is null and this map does not permit null keys; IllegalArgumentException - if this map itself has a restricted range, and fromKey lies outside the bounds of the range

subMap

ConcurrentNavigableMap<K,V> subMap(K fromKey, K toKey)

Description copied from interface: NavigableMap

Returns a view of the portion of this map whose keys range from fromKey, inclusive, to toKey, exclusive. (If fromKey and toKey are equal, the returned map is empty.) The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports.

The returned map will throw an IllegalArgumentException on an attempt to insert a key outside its range.

Equivalent to subMap(fromKey, true, toKey, false).

Specified by:: subMap in interface NavigableMap<K,V>
Specified by:: subMap in interface SortedMap<K,V>
Parameters:: fromKey - low endpoint (inclusive) of the keys in the returned map; toKey - high endpoint (exclusive) of the keys in the returned map
Returns:: a view of the portion of this map whose keys range from fromKey, inclusive, to toKey, exclusive
Throws:: ClassCastException - if fromKey and toKey cannot be compared to one another using this map's comparator (or, if the map has no comparator, using natural ordering). Implementations may, but are not required to, throw this exception if fromKey or toKey cannot be compared to keys currently in the map.; NullPointerException - if fromKey or toKey is null and this map does not permit null keys; IllegalArgumentException - if fromKey is greater than toKey; or if this map itself has a restricted range, and fromKey or toKey lies outside the bounds of the range

headMap

ConcurrentNavigableMap<K,V> headMap(K toKey)

Description copied from interface: NavigableMap

Returns a view of the portion of this map whose keys are strictly less than toKey. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports.

The returned map will throw an IllegalArgumentException on an attempt to insert a key outside its range.

Equivalent to headMap(toKey, false).

Specified by:: headMap in interface NavigableMap<K,V>
Specified by:: headMap in interface SortedMap<K,V>
Parameters:: toKey - high endpoint (exclusive) of the keys in the returned map
Returns:: a view of the portion of this map whose keys are strictly less than toKey
Throws:: ClassCastException - if toKey is not compatible with this map's comparator (or, if the map has no comparator, if toKey does not implement Comparable). Implementations may, but are not required to, throw this exception if toKey cannot be compared to keys currently in the map.; NullPointerException - if toKey is null and this map does not permit null keys; IllegalArgumentException - if this map itself has a restricted range, and toKey lies outside the bounds of the range

tailMap

ConcurrentNavigableMap<K,V> tailMap(K fromKey)

Description copied from interface: NavigableMap

Returns a view of the portion of this map whose keys are greater than or equal to fromKey. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports.

The returned map will throw an IllegalArgumentException on an attempt to insert a key outside its range.

Equivalent to tailMap(fromKey, true).

Specified by:: tailMap in interface NavigableMap<K,V>
Specified by:: tailMap in interface SortedMap<K,V>
Parameters:: fromKey - low endpoint (inclusive) of the keys in the returned map
Returns:: a view of the portion of this map whose keys are greater than or equal to fromKey
Throws:: ClassCastException - if fromKey is not compatible with this map's comparator (or, if the map has no comparator, if fromKey does not implement Comparable). Implementations may, but are not required to, throw this exception if fromKey cannot be compared to keys currently in the map.; NullPointerException - if fromKey is null and this map does not permit null keys; IllegalArgumentException - if this map itself has a restricted range, and fromKey lies outside the bounds of the range

descendingMap

ConcurrentNavigableMap<K,V> descendingMap()

Returns a reverse order view of the mappings contained in this map. The descending map is backed by this map, so changes to the map are reflected in the descending map, and vice-versa.

The returned map has an ordering equivalent to Collections.reverseOrder(comparator()). The expression m.descendingMap().descendingMap() returns a view of m essentially equivalent to m.

Specified by:: descendingMap in interface NavigableMap<K,V>
Returns:: a reverse order view of this map

navigableKeySet

NavigableSet<K> navigableKeySet()

Returns a NavigableSet view of the keys contained in this map. The set's iterator returns the keys in ascending order. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

The view's iterators and spliterators are weakly consistent.

Specified by:: navigableKeySet in interface NavigableMap<K,V>
Returns:: a navigable set view of the keys in this map

keySet

NavigableSet<K> keySet()

The view's iterators and spliterators are weakly consistent.

This method is equivalent to method navigableKeySet.

Specified by:: keySet in interface Map<K,V>
Specified by:: keySet in interface SortedMap<K,V>
Returns:: a navigable set view of the keys in this map

descendingKeySet

NavigableSet<K> descendingKeySet()

Returns a reverse order NavigableSet view of the keys contained in this map. The set's iterator returns the keys in descending order. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

The view's iterators and spliterators are weakly consistent.

Specified by:: descendingKeySet in interface NavigableMap<K,V>
Returns:: a reverse order navigable set view of the keys in this map

© 1993, 2025, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.