Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels) Summary: [Methods](https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap#pubmethods) \| [Inherited Methods](https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap#inhmethods)

# ConcurrentNavigableMap

` public interface ConcurrentNavigableMap `   
` implements https://developer.android.com/reference/java/util/concurrent/ConcurrentMap<K, V>, https://developer.android.com/reference/java/util/NavigableMap<K, V> `

|---|
| java.util.concurrent.ConcurrentNavigableMap\<K, V\> |

Known indirect subclasses [ConcurrentSkipListMap](https://developer.android.com/reference/java/util/concurrent/ConcurrentSkipListMap)\<K, V\> [ConcurrentSkipListMap](https://developer.android.com/reference/java/util/concurrent/ConcurrentSkipListMap)\<K, V\> A scalable concurrent `https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap` implementation.   

*** ** * ** ***

A `https://developer.android.com/reference/java/util/concurrent/ConcurrentMap` supporting `https://developer.android.com/reference/java/util/NavigableMap` operations, and recursively so for its navigable sub-maps.

This interface is a member of the [Java Collections Framework](https://reference/java/util/package-summary.html#CollectionsFramework).

## Summary

| ### Public methods ||
|---|---|
| ` abstract https://developer.android.com/reference/java/util/NavigableSet<K>` | ` https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap#descendingKeySet()() ` Returns a reverse order `https://developer.android.com/reference/java/util/NavigableSet` view of the keys contained in this map. |
| ` abstract https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | ` https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap#descendingMap()() ` Returns a reverse order view of the mappings contained in this map. |
| ` abstract https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | ` https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap#headMap(K)(K toKey) ` Returns a view of the portion of this map whose keys are strictly less than `toKey`. Equivalent to `headMap(toKey, false)`. |
| ` abstract https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | ` https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap#headMap(K,%20boolean)(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`. |
| ` abstract https://developer.android.com/reference/java/util/NavigableSet<K>` | ` https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap#keySet()() ` Returns a `https://developer.android.com/reference/java/util/NavigableSet` view of the keys contained in this map. |
| ` abstract https://developer.android.com/reference/java/util/NavigableSet<K>` | ` https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap#navigableKeySet()() ` Returns a `https://developer.android.com/reference/java/util/NavigableSet` view of the keys contained in this map. |
| ` abstract https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | ` https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap#subMap(K,%20K)(K fromKey, K toKey) ` Returns a view of the portion of this map whose keys range from `fromKey`, inclusive, to `toKey`, exclusive. Equivalent to `subMap(fromKey, true, toKey, false)`. |
| ` abstract https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | ` https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap#subMap(K,%20boolean,%20K,%20boolean)(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) ` Returns a view of the portion of this map whose keys range from `fromKey` to `toKey`. |
| ` abstract https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | ` https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap#tailMap(K,%20boolean)(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`. |
| ` abstract https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | ` https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap#tailMap(K)(K fromKey) ` Returns a view of the portion of this map whose keys are greater than or equal to `fromKey`. Equivalent to `tailMap(fromKey, true)`. |

### Inherited methods

From interface ` https://developer.android.com/reference/java/util/concurrent/ConcurrentMap ` ` default V` ` https://developer.android.com/reference/java/util/concurrent/ConcurrentMap#compute(K,%20java.util.function.BiFunction<?%20super%20K,?%20super%20V,?%20extends%20V>)(K key, https://developer.android.com/reference/java/util/function/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` ` https://developer.android.com/reference/java/util/concurrent/ConcurrentMap#computeIfAbsent(K,%20java.util.function.Function<?%20super%20K,?%20extends%20V>)(K key, https://developer.android.com/reference/java/util/function/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` ` https://developer.android.com/reference/java/util/concurrent/ConcurrentMap#computeIfPresent(K,%20java.util.function.BiFunction<?%20super%20K,?%20super%20V,?%20extends%20V>)(K key, https://developer.android.com/reference/java/util/function/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` ` https://developer.android.com/reference/java/util/concurrent/ConcurrentMap#forEach(java.util.function.BiConsumer<?%20super%20K,?%20super%20V>)(https://developer.android.com/reference/java/util/function/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` ` https://developer.android.com/reference/java/util/concurrent/ConcurrentMap#getOrDefault(java.lang.Object,%20V)(https://developer.android.com/reference/java/lang/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` ` https://developer.android.com/reference/java/util/concurrent/ConcurrentMap#merge(K,%20V,%20java.util.function.BiFunction<?%20super%20V,?%20super%20V,?%20extends%20V>)(K key, V value, https://developer.android.com/reference/java/util/function/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).
` abstract V` ` https://developer.android.com/reference/java/util/concurrent/ConcurrentMap#putIfAbsent(K,%20V)(K key, V value) `

If the specified key is not already associated with a value, associates it with the given value.
` abstract boolean` ` https://developer.android.com/reference/java/util/concurrent/ConcurrentMap#remove(java.lang.Object,%20java.lang.Object)(https://developer.android.com/reference/java/lang/Object key, https://developer.android.com/reference/java/lang/Object value) `

Removes the entry for a key only if currently mapped to a given value.
` abstract boolean` ` https://developer.android.com/reference/java/util/concurrent/ConcurrentMap#replace(K,%20V,%20V)(K key, V oldValue, V newValue) `

Replaces the entry for a key only if currently mapped to a given value.
` abstract V` ` https://developer.android.com/reference/java/util/concurrent/ConcurrentMap#replace(K,%20V)(K key, V value) `

Replaces the entry for a key only if currently mapped to some value.
` default void` ` https://developer.android.com/reference/java/util/concurrent/ConcurrentMap#replaceAll(java.util.function.BiFunction<?%20super%20K,?%20super%20V,?%20extends%20V>)(https://developer.android.com/reference/java/util/function/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).
From interface ` https://developer.android.com/reference/java/util/NavigableMap ` ` abstract https://developer.android.com/reference/java/util/Map.Entry<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#ceilingEntry(K)(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.
` abstract K` ` https://developer.android.com/reference/java/util/NavigableMap#ceilingKey(K)(K key) `

Returns the least key greater than or equal to the given key, or `null` if there is no such key.
` abstract https://developer.android.com/reference/java/util/NavigableSet<K>` ` https://developer.android.com/reference/java/util/NavigableMap#descendingKeySet()() `

Returns a reverse order `https://developer.android.com/reference/java/util/NavigableSet` view of the keys contained in this map.
` abstract https://developer.android.com/reference/java/util/NavigableMap<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#descendingMap()() `

Returns a reverse order view of the mappings contained in this map.
` abstract https://developer.android.com/reference/java/util/Map.Entry<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#firstEntry()() `

Returns a key-value mapping associated with the least key in this map, or `null` if the map is empty.
` abstract https://developer.android.com/reference/java/util/Map.Entry<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#floorEntry(K)(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.
` abstract K` ` https://developer.android.com/reference/java/util/NavigableMap#floorKey(K)(K key) `

Returns the greatest key less than or equal to the given key, or `null` if there is no such key.
` abstract https://developer.android.com/reference/java/util/SortedMap<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#headMap(K)(K toKey) `

Returns a view of the portion of this map whose keys are strictly less than `toKey`.

Equivalent to `headMap(toKey, false)`.
` abstract https://developer.android.com/reference/java/util/NavigableMap<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#headMap(K,%20boolean)(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`.
` abstract https://developer.android.com/reference/java/util/Map.Entry<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#higherEntry(K)(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.
` abstract K` ` https://developer.android.com/reference/java/util/NavigableMap#higherKey(K)(K key) `

Returns the least key strictly greater than the given key, or `null` if there is no such key.
` abstract https://developer.android.com/reference/java/util/Map.Entry<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#lastEntry()() `

Returns a key-value mapping associated with the greatest key in this map, or `null` if the map is empty.
` abstract https://developer.android.com/reference/java/util/Map.Entry<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#lowerEntry(K)(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.
` abstract K` ` https://developer.android.com/reference/java/util/NavigableMap#lowerKey(K)(K key) `

Returns the greatest key strictly less than the given key, or `null` if there is no such key.
` abstract https://developer.android.com/reference/java/util/NavigableSet<K>` ` https://developer.android.com/reference/java/util/NavigableMap#navigableKeySet()() `

Returns a `https://developer.android.com/reference/java/util/NavigableSet` view of the keys contained in this map.
` abstract https://developer.android.com/reference/java/util/Map.Entry<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#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).
` abstract https://developer.android.com/reference/java/util/Map.Entry<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#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 https://developer.android.com/reference/java/util/NavigableMap<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#reversed()() `

Returns a reverse-ordered [view](https://developer.android.com/reference/java/util/concurrent/Collection#view) of this map.

This method is equivalent to `https://developer.android.com/reference/java/util/NavigableMap#descendingMap()`.
` abstract https://developer.android.com/reference/java/util/SortedMap<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#subMap(K,%20K)(K fromKey, K toKey) `

Returns a view of the portion of this map whose keys range from `fromKey`, inclusive, to `toKey`, exclusive.

Equivalent to `subMap(fromKey, true, toKey, false)`.
` abstract https://developer.android.com/reference/java/util/NavigableMap<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#subMap(K,%20boolean,%20K,%20boolean)(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive) `

Returns a view of the portion of this map whose keys range from `fromKey` to `toKey`.
` abstract https://developer.android.com/reference/java/util/NavigableMap<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#tailMap(K,%20boolean)(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`.
` abstract https://developer.android.com/reference/java/util/SortedMap<K, V>` ` https://developer.android.com/reference/java/util/NavigableMap#tailMap(K)(K fromKey) `

Returns a view of the portion of this map whose keys are greater than or equal to `fromKey`.

Equivalent to `tailMap(fromKey, true)`.
From interface ` https://developer.android.com/reference/java/util/Map ` ` abstract void` ` https://developer.android.com/reference/java/util/Map#clear()() `

Removes all of the mappings from this map (optional operation).
` default V` ` https://developer.android.com/reference/java/util/Map#compute(K,%20java.util.function.BiFunction<?%20super%20K,?%20super%20V,?%20extends%20V>)(K key, https://developer.android.com/reference/java/util/function/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` ` https://developer.android.com/reference/java/util/Map#computeIfAbsent(K,%20java.util.function.Function<?%20super%20K,?%20extends%20V>)(K key, https://developer.android.com/reference/java/util/function/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` ` https://developer.android.com/reference/java/util/Map#computeIfPresent(K,%20java.util.function.BiFunction<?%20super%20K,?%20super%20V,?%20extends%20V>)(K key, https://developer.android.com/reference/java/util/function/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).
` abstract boolean` ` https://developer.android.com/reference/java/util/Map#containsKey(java.lang.Object)(https://developer.android.com/reference/java/lang/Object key) `

Returns `true` if this map contains a mapping for the specified key.
` abstract boolean` ` https://developer.android.com/reference/java/util/Map#containsValue(java.lang.Object)(https://developer.android.com/reference/java/lang/Object value) `

Returns `true` if this map maps one or more keys to the specified value.
` static <K, V> https://developer.android.com/reference/java/util/Map<K, V>` ` https://developer.android.com/reference/java/util/Map#copyOf(java.util.Map<?%20extends%20K,?%20extends%20V>)(https://developer.android.com/reference/java/util/Map<? extends K, ? extends V> map) `

Returns an [unmodifiable Map](https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap#unmodifiable) containing the entries of the given Map.
` static <K, V> https://developer.android.com/reference/java/util/Map.Entry<K, V>` ` https://developer.android.com/reference/java/util/Map#entry(K,%20V)(K k, V v) `

Returns an unmodifiable `https://developer.android.com/reference/java/util/Map.Entry` containing the given key and value.
` abstract https://developer.android.com/reference/java/util/Set<https://developer.android.com/reference/java/util/Map.Entry<K, V>>` ` https://developer.android.com/reference/java/util/Map#entrySet()() `

Returns a `https://developer.android.com/reference/java/util/Set` view of the mappings contained in this map.
` abstract boolean` ` https://developer.android.com/reference/java/util/Map#equals(java.lang.Object)(https://developer.android.com/reference/java/lang/Object o) `

Compares the specified object with this map for equality.
` default void` ` https://developer.android.com/reference/java/util/Map#forEach(java.util.function.BiConsumer<?%20super%20K,?%20super%20V>)(https://developer.android.com/reference/java/util/function/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.
` abstract V` ` https://developer.android.com/reference/java/util/Map#get(java.lang.Object)(https://developer.android.com/reference/java/lang/Object key) `

Returns the value to which the specified key is mapped, or `null` if this map contains no mapping for the key.
` default V` ` https://developer.android.com/reference/java/util/Map#getOrDefault(java.lang.Object,%20V)(https://developer.android.com/reference/java/lang/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.
` abstract int` ` https://developer.android.com/reference/java/util/Map#hashCode()() `

Returns the hash code value for this map.
` abstract boolean` ` https://developer.android.com/reference/java/util/Map#isEmpty()() `

Returns `true` if this map contains no key-value mappings.
` abstract https://developer.android.com/reference/java/util/Set<K>` ` https://developer.android.com/reference/java/util/Map#keySet()() `

Returns a `https://developer.android.com/reference/java/util/Set` view of the keys contained in this map.
` default V` ` https://developer.android.com/reference/java/util/Map#merge(K,%20V,%20java.util.function.BiFunction<?%20super%20V,?%20super%20V,?%20extends%20V>)(K key, V value, https://developer.android.com/reference/java/util/function/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).
` static <K, V> https://developer.android.com/reference/java/util/Map<K, V>` ` https://developer.android.com/reference/java/util/Map#of(K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V)(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5) `

Returns an unmodifiable map containing five mappings.
` static <K, V> https://developer.android.com/reference/java/util/Map<K, V>` ` https://developer.android.com/reference/java/util/Map#of(K,%20V,%20K,%20V,%20K,%20V,%20K,%20V)(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) `

Returns an unmodifiable map containing four mappings.
` static <K, V> https://developer.android.com/reference/java/util/Map<K, V>` ` https://developer.android.com/reference/java/util/Map#of(K,%20V)(K k1, V v1) `

Returns an unmodifiable map containing a single mapping.
` static <K, V> https://developer.android.com/reference/java/util/Map<K, V>` ` https://developer.android.com/reference/java/util/Map#of(K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V)(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7, K k8, V v8) `

Returns an unmodifiable map containing eight mappings.
` static <K, V> https://developer.android.com/reference/java/util/Map<K, V>` ` https://developer.android.com/reference/java/util/Map#of(K,%20V,%20K,%20V)(K k1, V v1, K k2, V v2) `

Returns an unmodifiable map containing two mappings.
` static <K, V> https://developer.android.com/reference/java/util/Map<K, V>` ` https://developer.android.com/reference/java/util/Map#of(K,%20V,%20K,%20V,%20K,%20V)(K k1, V v1, K k2, V v2, K k3, V v3) `

Returns an unmodifiable map containing three mappings.
` static <K, V> https://developer.android.com/reference/java/util/Map<K, V>` ` https://developer.android.com/reference/java/util/Map#of()() `

Returns an unmodifiable map containing zero mappings.
` static <K, V> https://developer.android.com/reference/java/util/Map<K, V>` ` https://developer.android.com/reference/java/util/Map#of(K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V)(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7, K k8, V v8, K k9, V v9) `

Returns an unmodifiable map containing nine mappings.
` static <K, V> https://developer.android.com/reference/java/util/Map<K, V>` ` https://developer.android.com/reference/java/util/Map#of(K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V)(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6) `

Returns an unmodifiable map containing six mappings.
` static <K, V> https://developer.android.com/reference/java/util/Map<K, V>` ` https://developer.android.com/reference/java/util/Map#of(K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V)(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7) `

Returns an unmodifiable map containing seven mappings.
` static <K, V> https://developer.android.com/reference/java/util/Map<K, V>` ` https://developer.android.com/reference/java/util/Map#of(K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V,%20K,%20V)(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5, K k6, V v6, K k7, V v7, K k8, V v8, K k9, V v9, K k10, V v10) `

Returns an unmodifiable map containing ten mappings.
` static <K, V> https://developer.android.com/reference/java/util/Map<K, V>` ` https://developer.android.com/reference/java/util/Map#ofEntries(java.util.Map.Entry<?%20extends%20K,?%20extends%20V>[])(https://developer.android.com/reference/java/util/Map.Entry<? extends K, ? extends V> entries) `

Returns an unmodifiable map containing keys and values extracted from the given entries.
` abstract V` ` https://developer.android.com/reference/java/util/Map#put(K,%20V)(K key, V value) `

Associates the specified value with the specified key in this map (optional operation).
` abstract void` ` https://developer.android.com/reference/java/util/Map#putAll(java.util.Map<?%20extends%20K,?%20extends%20V>)(https://developer.android.com/reference/java/util/Map<? extends K, ? extends V> m) `

Copies all of the mappings from the specified map to this map (optional operation).
` default V` ` https://developer.android.com/reference/java/util/Map#putIfAbsent(K,%20V)(K key, V value) `

If the specified key is not already associated with a value (or is mapped to `null`) associates it with the given value and returns `null`, else returns the current value (optional operation).
` default boolean` ` https://developer.android.com/reference/java/util/Map#remove(java.lang.Object,%20java.lang.Object)(https://developer.android.com/reference/java/lang/Object key, https://developer.android.com/reference/java/lang/Object value) `

Removes the entry for the specified key only if it is currently mapped to the specified value (optional operation).
` abstract V` ` https://developer.android.com/reference/java/util/Map#remove(java.lang.Object)(https://developer.android.com/reference/java/lang/Object key) `

Removes the mapping for a key from this map if it is present (optional operation).
` default boolean` ` https://developer.android.com/reference/java/util/Map#replace(K,%20V,%20V)(K key, V oldValue, V newValue) `

Replaces the entry for the specified key only if currently mapped to the specified value (optional operation).
` default V` ` https://developer.android.com/reference/java/util/Map#replace(K,%20V)(K key, V value) `

Replaces the entry for the specified key only if it is currently mapped to some value (optional operation).
` default void` ` https://developer.android.com/reference/java/util/Map#replaceAll(java.util.function.BiFunction<?%20super%20K,?%20super%20V,?%20extends%20V>)(https://developer.android.com/reference/java/util/function/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).
` abstract int` ` https://developer.android.com/reference/java/util/Map#size()() `

Returns the number of key-value mappings in this map.
` abstract https://developer.android.com/reference/java/util/Collection<V>` ` https://developer.android.com/reference/java/util/Map#values()() `

Returns a `https://developer.android.com/reference/java/util/Collection` view of the values contained in this map.
From interface ` https://developer.android.com/reference/java/util/SortedMap ` ` abstract https://developer.android.com/reference/java/util/Comparator<? super K>` ` https://developer.android.com/reference/java/util/SortedMap#comparator()() `

Returns the comparator used to order the keys in this map, or `null` if this map uses the [natural ordering](https://developer.android.com/reference/java/lang/Comparable) of its keys.
` abstract https://developer.android.com/reference/java/util/Set<https://developer.android.com/reference/java/util/Map.Entry<K, V>>` ` https://developer.android.com/reference/java/util/SortedMap#entrySet()() `

Returns a `https://developer.android.com/reference/java/util/Set` view of the mappings contained in this map.
` abstract K` ` https://developer.android.com/reference/java/util/SortedMap#firstKey()() `

Returns the first (lowest) key currently in this map.
` abstract https://developer.android.com/reference/java/util/SortedMap<K, V>` ` https://developer.android.com/reference/java/util/SortedMap#headMap(K)(K toKey) `

Returns a view of the portion of this map whose keys are strictly less than `toKey`.
` abstract https://developer.android.com/reference/java/util/Set<K>` ` https://developer.android.com/reference/java/util/SortedMap#keySet()() `

Returns a `https://developer.android.com/reference/java/util/Set` view of the keys contained in this map.
` abstract K` ` https://developer.android.com/reference/java/util/SortedMap#lastKey()() `

Returns the last (highest) key currently in this map.
` default V` ` https://developer.android.com/reference/java/util/SortedMap#putFirst(K,%20V)(K k, V v) `

Throws `UnsupportedOperationException`.
` default V` ` https://developer.android.com/reference/java/util/SortedMap#putLast(K,%20V)(K k, V v) `

Throws `UnsupportedOperationException`.
` default https://developer.android.com/reference/java/util/SortedMap<K, V>` ` https://developer.android.com/reference/java/util/SortedMap#reversed()() `

Returns a reverse-ordered [view](https://developer.android.com/reference/java/util/concurrent/Collection#view) of this map.
` abstract https://developer.android.com/reference/java/util/SortedMap<K, V>` ` https://developer.android.com/reference/java/util/SortedMap#subMap(K,%20K)(K fromKey, K toKey) `

Returns a view of the portion of this map whose keys range from `fromKey`, inclusive, to `toKey`, exclusive.
` abstract https://developer.android.com/reference/java/util/SortedMap<K, V>` ` https://developer.android.com/reference/java/util/SortedMap#tailMap(K)(K fromKey) `

Returns a view of the portion of this map whose keys are greater than or equal to `fromKey`.
` abstract https://developer.android.com/reference/java/util/Collection<V>` ` https://developer.android.com/reference/java/util/SortedMap#values()() `

Returns a `https://developer.android.com/reference/java/util/Collection` view of the values contained in this map.
From interface ` https://developer.android.com/reference/java/util/SequencedMap ` ` default https://developer.android.com/reference/java/util/Map.Entry<K, V>` ` https://developer.android.com/reference/java/util/SequencedMap#firstEntry()() `

Returns the first key-value mapping in this map, or `null` if the map is empty.
` default https://developer.android.com/reference/java/util/Map.Entry<K, V>` ` https://developer.android.com/reference/java/util/SequencedMap#lastEntry()() `

Returns the last key-value mapping in this map, or `null` if the map is empty.
` default https://developer.android.com/reference/java/util/Map.Entry<K, V>` ` https://developer.android.com/reference/java/util/SequencedMap#pollFirstEntry()() `

Removes and returns the first key-value mapping in this map, or `null` if the map is empty (optional operation).
` default https://developer.android.com/reference/java/util/Map.Entry<K, V>` ` https://developer.android.com/reference/java/util/SequencedMap#pollLastEntry()() `

Removes and returns the last key-value mapping in this map, or `null` if the map is empty (optional operation).
` default V` ` https://developer.android.com/reference/java/util/SequencedMap#putFirst(K,%20V)(K k, V v) `

Inserts the given mapping into the map if it is not already present, or replaces the value of a mapping if it is already present (optional operation).
` default V` ` https://developer.android.com/reference/java/util/SequencedMap#putLast(K,%20V)(K k, V v) `

Inserts the given mapping into the map if it is not already present, or replaces the value of a mapping if it is already present (optional operation).
` abstract https://developer.android.com/reference/java/util/SequencedMap<K, V>` ` https://developer.android.com/reference/java/util/SequencedMap#reversed()() `

Returns a reverse-ordered [view](https://developer.android.com/reference/java/util/concurrent/Collection#view) of this map.
` default https://developer.android.com/reference/java/util/SequencedSet<https://developer.android.com/reference/java/util/Map.Entry<K, V>>` ` https://developer.android.com/reference/java/util/SequencedMap#sequencedEntrySet()() `

Returns a `SequencedSet` view of this map's `https://developer.android.com/reference/java/util/Map#entrySet()`.
` default https://developer.android.com/reference/java/util/SequencedSet<K>` ` https://developer.android.com/reference/java/util/SequencedMap#sequencedKeySet()() `

Returns a `SequencedSet` view of this map's `https://developer.android.com/reference/java/util/Map#keySet()`.
` default https://developer.android.com/reference/java/util/SequencedCollection<V>` ` https://developer.android.com/reference/java/util/SequencedMap#sequencedValues()() `

Returns a `SequencedCollection` view of this map's `https://developer.android.com/reference/java/util/Map#values()` collection.

## Public methods

### descendingKeySet

Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract NavigableSet<K> descendingKeySet ()
```

Returns a reverse order `https://developer.android.com/reference/java/util/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*](https://developer.android.com/reference/java/util/concurrent/package-summary#Weakly).

<br />

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/NavigableSet<K>` | a reverse order navigable set view of the keys in this map <br /> |

### descendingMap

Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract 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 `https://developer.android.com/reference/java/util/Collections#reverseOrder(java.util.Comparator<T>)``(comparator())`. The expression `m.descendingMap().descendingMap()` returns a view of `m` essentially equivalent to `m`.

<br />

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | a reverse order view of this map <br /> |

### headMap

Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract ConcurrentNavigableMap<K, V> headMap (K toKey)
```

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)`.

<br />

| Parameters ||
|---|---|
| `toKey` | `K`: high endpoint (exclusive) of the keys in the returned map <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | a view of the portion of this map whose keys are strictly less than `toKey` <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` |   |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` |   |
| `https://developer.android.com/reference/java/lang/NullPointerException` |   |

### headMap

Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract 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`. 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.

<br />

| Parameters ||
|---|---|
| `toKey` | `K`: high endpoint of the keys in the returned map <br /> |
| `inclusive` | `boolean`: `true` if the high endpoint is to be included in the returned view <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | a view of the portion of this map whose keys are less than (or equal to, if `inclusive` is true) `toKey` <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` |   |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` |   |
| `https://developer.android.com/reference/java/lang/NullPointerException` |   |

### keySet

Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract NavigableSet<K> keySet ()
```

Returns a `https://developer.android.com/reference/java/util/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*](https://developer.android.com/reference/java/util/concurrent/package-summary#Weakly).

This method is equivalent to method `navigableKeySet`.

<br />

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/NavigableSet<K>` | a navigable set view of the keys in this map <br /> |

### navigableKeySet

Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract NavigableSet<K> navigableKeySet ()
```

Returns a `https://developer.android.com/reference/java/util/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*](https://developer.android.com/reference/java/util/concurrent/package-summary#Weakly).

<br />

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/NavigableSet<K>` | a navigable set view of the keys in this map <br /> |

### subMap

Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract 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. (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)`.

<br />

| Parameters ||
|---|---|
| `fromKey` | `K`: low endpoint (inclusive) of the keys in the returned map <br /> |
| `toKey` | `K`: high endpoint (exclusive) of the keys in the returned map <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | a view of the portion of this map whose keys range from `fromKey`, inclusive, to `toKey`, exclusive <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` |   |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` |   |
| `https://developer.android.com/reference/java/lang/NullPointerException` |   |

### subMap

Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract 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`. 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.

<br />

| Parameters ||
|---|---|
| `fromKey` | `K`: low endpoint of the keys in the returned map <br /> |
| `fromInclusive` | `boolean`: `true` if the low endpoint is to be included in the returned view <br /> |
| `toKey` | `K`: high endpoint of the keys in the returned map <br /> |
| `toInclusive` | `boolean`: `true` if the high endpoint is to be included in the returned view <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | a view of the portion of this map whose keys range from `fromKey` to `toKey` <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` |   |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` |   |
| `https://developer.android.com/reference/java/lang/NullPointerException` |   |

### tailMap

Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract 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`. 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.

<br />

| Parameters ||
|---|---|
| `fromKey` | `K`: low endpoint of the keys in the returned map <br /> |
| `inclusive` | `boolean`: `true` if the low endpoint is to be included in the returned view <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | a view of the portion of this map whose keys are greater than (or equal to, if `inclusive` is true) `fromKey` <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` |   |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` |   |
| `https://developer.android.com/reference/java/lang/NullPointerException` |   |

### tailMap

Added in [API level 9](https://developer.android.com/guide/topics/manifest/uses-sdk-element#ApiLevels)

```
public abstract ConcurrentNavigableMap<K, V> tailMap (K fromKey)
```

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)`.

<br />

| Parameters ||
|---|---|
| `fromKey` | `K`: low endpoint (inclusive) of the keys in the returned map <br /> |

| Returns ||
|---|---|
| `https://developer.android.com/reference/java/util/concurrent/ConcurrentNavigableMap<K, V>` | a view of the portion of this map whose keys are greater than or equal to `fromKey` <br /> |

| Throws ||
|---|---|
| `https://developer.android.com/reference/java/lang/ClassCastException` |   |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException` |   |
| `https://developer.android.com/reference/java/lang/NullPointerException` |   |