Package Summary Overview Summary

### class:TreeMap [NONE]
- Type Parameters: `K` - the type of keys maintained by this map `V` - the type of mapped values All Implemented Interfaces: `Serializable`, `Cloneable`, `Map<K,V>`, `NavigableMap<K,V>`, `SortedMap<K,V>`
                                                                                      public class TreeMap<K,V>
      extends AbstractMap<K,V>
      implements NavigableMap<K,V>, Cloneable, Serializable
  A Red-Black tree based `NavigableMap` implementation. The map is sorted according to the natural ordering of its keys, or by a `Comparator` provided at map creation time, depending on which constructor is used. This implementation provides guaranteed log(n) time cost for the `containsKey`, `get`, `put` and `remove` operations. Algorithms are adaptations of those in Cormen, Leiserson, and Rivest's Introduction to Algorithms . Note that the ordering maintained by a tree map, like any sorted map, and whether or not an explicit comparator is provided, must be consistent with `equals` if this sorted map is to correctly implement the `Map` interface. (See `Comparable` or `Comparator` for a precise definition of consistent with equals .) This is so because the `Map` interface is defined in terms of the `equals` operation, but a sorted map performs all key comparisons using its `compareTo` (or `compare`) method, so two keys that are deemed equal by this method are, from the standpoint of the sorted map, equal. The behavior of a sorted map is well-defined even if its ordering is inconsistent with `equals`; it just fails to obey the general contract of the `Map` interface. Note that this implementation is not synchronized. If multiple threads access a map concurrently, and at least one of the threads modifies the map structurally, it must be synchronized externally. (A structural modification is any operation that adds or deletes one or more mappings; merely changing the value associated with an existing key is not a structural modification.) This is typically accomplished by synchronizing on some object that naturally encapsulates the map. If no such object exists, the map should be "wrapped" using the `Collections.synchronizedSortedMap` method. This is best done at creation time, to prevent accidental unsynchronized access to the map:
         SortedMap m = Collections.synchronizedSortedMap(new TreeMap(...));
The iterators returned by the `iterator` method of the collections returned by all of this class's "collection view methods" are fail-fast: if the map is structurally modified at any time after the iterator is created, in any way except through the iterator's own `remove` method, the iterator will throw a `ConcurrentModificationException`. Thus, in the face of concurrent modification, the iterator fails quickly and cleanly, rather than risking arbitrary, non-deterministic behavior at an undetermined time in the future. Note that the fail-fast behavior of an iterator cannot be guaranteed as it is, generally speaking, impossible to make any hard guarantees in the presence of unsynchronized concurrent modification. Fail-fast iterators throw `ConcurrentModificationException` on a best-effort basis. Therefore, it would be wrong to write a program that depended on this exception for its correctness: the fail-fast behavior of iterators should be used only to detect bugs. All `Map.Entry` pairs returned by methods in this class and its views represent snapshots of mappings at the time they were produced. They do not support the `Entry.setValue` method. (Note however that it is possible to change mappings in the associated map using `put`.) This class is a member of the Java Collections Framework . Since: 1.2 See Also: `Map`, `HashMap`, `Hashtable`, `Comparable`, `Comparator`, `Collection`, Serialized Form

### constructor:<init>() [NONE]
- #### TreeMap
      public TreeMap()
Constructs a new, empty tree map, using the natural ordering of its keys. All keys inserted into the map must implement the `Comparable` interface. Furthermore, all such keys must be mutually comparable : `k1.compareTo(k2)` must not throw a `ClassCastException` for any keys `k1` and `k2` in the map. If the user attempts to put a key into the map that violates this constraint (for example, the user attempts to put a string key into a map whose keys are integers), the `put(Object key, Object value)` call will throw a `ClassCastException`.

### constructor:<init>(java.util.Comparator) [NONE]
- #### TreeMap
                                                                                                      public TreeMap​(Comparator<? super K> comparator)
Constructs a new, empty tree map, ordered according to the given comparator. All keys inserted into the map must be mutually comparable by the given comparator: `comparator.compare(k1, k2)` must not throw a `ClassCastException` for any keys `k1` and `k2` in the map. If the user attempts to put a key into the map that violates this constraint, the `put(Object key, Object value)` call will throw a `ClassCastException`. Parameters: `comparator` - the comparator that will be used to order this map. If `null`, the natural ordering of the keys will be used.

### constructor:<init>(java.util.Map) [NONE]
- #### TreeMap
                                                                                                      public 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. All keys inserted into the new map must implement the `Comparable` interface. Furthermore, all such keys must be mutually comparable : `k1.compareTo(k2)` must not throw a `ClassCastException` for any keys `k1` and `k2` in the map. This method runs in n*log(n) time. Parameters: `m` - the map whose mappings are to be placed in this map Throws: `ClassCastException` - if the keys in m are not `Comparable`, or are not mutually comparable `NullPointerException` - if the specified map is null

### constructor:<init>(java.util.SortedMap) [NONE]
- #### TreeMap
                                                                                                      public TreeMap​(SortedMap<K,? extends V> m)
Constructs a new tree map containing the same mappings and using the same ordering as the specified sorted map. This method runs in linear time. Parameters: `m` - the sorted map whose mappings are to be placed in this map, and whose comparator is to be used to sort this map Throws: `NullPointerException` - if the specified map is null

### method:size() [NONE]
- #### size
      public int size()
Returns the number of key-value mappings in this map. Specified by: `size` in interface `Map<K,V>` Overrides: `size` in class `AbstractMap<K,V>` Returns: the number of key-value mappings in this map

### method:containsKey(java.lang.Object) [NONE]
- #### containsKey
                                                                                                      public boolean containsKey​(Object key)
Returns `true` if this map contains a mapping for the specified key. Specified by: `containsKey` in interface `Map<K,V>` Overrides: `containsKey` in class `AbstractMap<K,V>` Parameters: `key` - key whose presence in this map is to be tested Returns: `true` if this map contains a mapping for the specified key Throws: `ClassCastException` - if the specified key cannot be compared with the keys currently in the map `NullPointerException` - if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys

### method:containsValue(java.lang.Object) [NONE]
- #### containsValue
                                                                                                      public boolean containsValue​(Object value)
Returns `true` if this map maps one or more keys to the specified value. More formally, returns `true` if and only if this map contains at least one mapping to a value `v` such that `(value==null ? v==null : value.equals(v))` . This operation will probably require time linear in the map size for most implementations. Specified by: `containsValue` in interface `Map<K,V>` Overrides: `containsValue` in class `AbstractMap<K,V>` Parameters: `value` - value whose presence in this map is to be tested Returns: `true` if a mapping to `value` exists; `false` otherwise Since: 1.2

### method:get(java.lang.Object) [NONE]
- #### get
                                                                                                      public 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. More formally, if this map contains a mapping from a key `k` to a value `v` such that `key` compares equal to `k` according to the map's ordering, then this method returns `v`; otherwise it returns `null`. (There can be at most one such mapping.) A return value of `null` does not necessarily indicate that the map contains no mapping for the key; it's also possible that the map explicitly maps the key to `null`. The `containsKey` operation may be used to distinguish these two cases. Specified by: `get` in interface `Map<K,V>` Overrides: `get` in class `AbstractMap<K,V>` Parameters: `key` - the key whose associated value is to be returned Returns: the value to which the specified key is mapped, or `null` if this map contains no mapping for the key Throws: `ClassCastException` - if the specified key cannot be compared with the keys currently in the map `NullPointerException` - if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys

### method:firstKey() [NONE]
- #### firstKey
                                                                                                      public K firstKey()
Description copied from interface: `SortedMap` Returns the first (lowest) key currently in this map. Specified by: `firstKey` in interface `SortedMap<K,V>` Returns: the first (lowest) key currently in this map Throws: `NoSuchElementException` - if this map is empty

### method:lastKey() [NONE]
- #### lastKey
                                                                                                      public K lastKey()
Description copied from interface: `SortedMap` Returns the last (highest) key currently in this map. Specified by: `lastKey` in interface `SortedMap<K,V>` Returns: the last (highest) key currently in this map Throws: `NoSuchElementException` - if this map is empty

### method:putAll(java.util.Map) [NONE]
- #### putAll
                                                                                                      public void putAll​(Map<? extends K,? extends V> map)
Copies all of the mappings from the specified map to this map. These mappings replace any mappings that this map had for any of the keys currently in the specified map. Specified by: `putAll` in interface `Map<K,V>` Overrides: `putAll` in class `AbstractMap<K,V>` Parameters: `map` - mappings to be stored in this map Throws: `ClassCastException` - if the class of a key or value in the specified map prevents it from being stored in this map `NullPointerException` - if the specified map is null or the specified map contains a null key and this map does not permit null keys

### method:put(K,V) [NONE]
- #### put
                                                                                                      public V put​(K key,
                   V value)
Associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the old value is replaced. Specified by: `put` in interface `Map<K,V>` Overrides: `put` in class `AbstractMap<K,V>` Parameters: `key` - key with which the specified value is to be associated `value` - value to be associated with the specified key Returns: the previous value associated with `key`, or `null` if there was no mapping for `key`. (A `null` return can also indicate that the map previously associated `null` with `key`.) Throws: `ClassCastException` - if the specified key cannot be compared with the keys currently in the map `NullPointerException` - if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys

### method:remove(java.lang.Object) [NONE]
- #### remove
                                                                                                      public V remove​(Object key)
Removes the mapping for this key from this TreeMap if present. Specified by: `remove` in interface `Map<K,V>` Overrides: `remove` in class `AbstractMap<K,V>` Parameters: `key` - key for which mapping should be removed Returns: the previous value associated with `key`, or `null` if there was no mapping for `key`. (A `null` return can also indicate that the map previously associated `null` with `key`.) Throws: `ClassCastException` - if the specified key cannot be compared with the keys currently in the map `NullPointerException` - if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys

### method:clear() [NONE]
- #### clear
      public void clear()
Removes all of the mappings from this map. The map will be empty after this call returns. Specified by: `clear` in interface `Map<K,V>` Overrides: `clear` in class `AbstractMap<K,V>`

### method:clone() [NONE]
- #### clone
                                                                                                      public Object clone()
Returns a shallow copy of this `TreeMap` instance. (The keys and values themselves are not cloned.) Overrides: `clone` in class `AbstractMap<K,V>` Returns: a shallow copy of this map See Also: `Cloneable`

### method:firstEntry() [NONE]
- #### firstEntry
                                                                                                      public Map.Entry<K,V> firstEntry()
Description copied from interface: `NavigableMap` Returns a key-value mapping associated with the least key in this map, or `null` if the map is empty. Specified by: `firstEntry` in interface `NavigableMap<K,V>` Returns: an entry with the least key, or `null` if this map is empty Since: 1.6

### method:lastEntry() [NONE]
- #### lastEntry
                                                                                                      public Map.Entry<K,V> lastEntry()
Description copied from interface: `NavigableMap` Returns a key-value mapping associated with the greatest key in this map, or `null` if the map is empty. Specified by: `lastEntry` in interface `NavigableMap<K,V>` Returns: an entry with the greatest key, or `null` if this map is empty Since: 1.6

### method:pollFirstEntry() [NONE]
- #### pollFirstEntry
                                                                                                      public Map.Entry<K,V> pollFirstEntry()
Description copied from interface: `NavigableMap` Removes and returns a key-value mapping associated with the least key in this map, or `null` if the map is empty. Specified by: `pollFirstEntry` in interface `NavigableMap<K,V>` Returns: the removed first entry of this map, or `null` if this map is empty Since: 1.6

### method:pollLastEntry() [NONE]
- #### pollLastEntry
                                                                                                      public Map.Entry<K,V> pollLastEntry()
Description copied from interface: `NavigableMap` Removes and returns a key-value mapping associated with the greatest key in this map, or `null` if the map is empty. Specified by: `pollLastEntry` in interface `NavigableMap<K,V>` Returns: the removed last entry of this map, or `null` if this map is empty Since: 1.6

### method:lowerEntry(K) [NONE]
- #### lowerEntry
                                                                                                      public Map.Entry<K,V> lowerEntry​(K key)
Description copied from interface: `NavigableMap` Returns a key-value mapping associated with the greatest key strictly less than the given key, or `null` if there is no such key. Specified by: `lowerEntry` in interface `NavigableMap<K,V>` Parameters: `key` - the key Returns: an entry with the greatest key less than `key`, or `null` if there is no such key Throws: `ClassCastException` - if the specified key cannot be compared with the keys currently in the map `NullPointerException` - if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys Since: 1.6

### method:lowerKey(K) [NONE]
- #### lowerKey
                                                                                                      public K lowerKey​(K key)
Description copied from interface: `NavigableMap` Returns the greatest key strictly less than the given key, or `null` if there is no such key. Specified by: `lowerKey` in interface `NavigableMap<K,V>` Parameters: `key` - the key Returns: the greatest key less than `key`, or `null` if there is no such key Throws: `ClassCastException` - if the specified key cannot be compared with the keys currently in the map `NullPointerException` - if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys Since: 1.6

### method:floorEntry(K) [NONE]
- #### floorEntry
                                                                                                      public Map.Entry<K,V> floorEntry​(K key)
Description copied from interface: `NavigableMap` 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. Specified by: `floorEntry` in interface `NavigableMap<K,V>` Parameters: `key` - the key Returns: an entry with the greatest key less than or equal to `key`, or `null` if there is no such key Throws: `ClassCastException` - if the specified key cannot be compared with the keys currently in the map `NullPointerException` - if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys Since: 1.6

### method:floorKey(K) [NONE]
- #### floorKey
                                                                                                      public K floorKey​(K key)
Description copied from interface: `NavigableMap` Returns the greatest key less than or equal to the given key, or `null` if there is no such key. Specified by: `floorKey` in interface `NavigableMap<K,V>` Parameters: `key` - the key Returns: the greatest key less than or equal to `key`, or `null` if there is no such key Throws: `ClassCastException` - if the specified key cannot be compared with the keys currently in the map `NullPointerException` - if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys Since: 1.6

### method:ceilingEntry(K) [NONE]
- #### ceilingEntry
                                                                                                      public Map.Entry<K,V> ceilingEntry​(K key)
Description copied from interface: `NavigableMap` 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. Specified by: `ceilingEntry` in interface `NavigableMap<K,V>` Parameters: `key` - the key Returns: an entry with the least key greater than or equal to `key`, or `null` if there is no such key Throws: `ClassCastException` - if the specified key cannot be compared with the keys currently in the map `NullPointerException` - if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys Since: 1.6

### method:ceilingKey(K) [NONE]
- #### ceilingKey
                                                                                                      public K ceilingKey​(K key)
Description copied from interface: `NavigableMap` Returns the least key greater than or equal to the given key, or `null` if there is no such key. Specified by: `ceilingKey` in interface `NavigableMap<K,V>` Parameters: `key` - the key Returns: the least key greater than or equal to `key`, or `null` if there is no such key Throws: `ClassCastException` - if the specified key cannot be compared with the keys currently in the map `NullPointerException` - if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys Since: 1.6

### method:higherEntry(K) [NONE]
- #### higherEntry
                                                                                                      public Map.Entry<K,V> higherEntry​(K key)
Description copied from interface: `NavigableMap` Returns a key-value mapping associated with the least key strictly greater than the given key, or `null` if there is no such key. Specified by: `higherEntry` in interface `NavigableMap<K,V>` Parameters: `key` - the key Returns: an entry with the least key greater than `key`, or `null` if there is no such key Throws: `ClassCastException` - if the specified key cannot be compared with the keys currently in the map `NullPointerException` - if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys Since: 1.6

### method:higherKey(K) [NONE]
- #### higherKey
                                                                                                      public K higherKey​(K key)
Description copied from interface: `NavigableMap` Returns the least key strictly greater than the given key, or `null` if there is no such key. Specified by: `higherKey` in interface `NavigableMap<K,V>` Parameters: `key` - the key Returns: the least key greater than `key`, or `null` if there is no such key Throws: `ClassCastException` - if the specified key cannot be compared with the keys currently in the map `NullPointerException` - if the specified key is null and this map uses natural ordering, or its comparator does not permit null keys Since: 1.6

### method:keySet() [NONE]
- #### keySet
                                                                                                      public Set<K> keySet()
Returns a `Set` view of the keys contained in this map. The set's iterator returns the keys in ascending order. The set's spliterator is late-binding, fail-fast, and additionally reports `Spliterator.SORTED` and `Spliterator.ORDERED` with an encounter order that is ascending key order. The spliterator's comparator (see `Spliterator.getComparator()`) is `null` if the tree map's comparator (see `SortedMap.comparator()`) is `null`. Otherwise, the spliterator's comparator is the same as or imposes the same total ordering as the tree map's comparator. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own `remove` operation), the results of the iteration are undefined. 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. Specified by: `keySet` in interface `Map<K,V>` Specified by: `keySet` in interface `SortedMap<K,V>` Overrides: `keySet` in class `AbstractMap<K,V>` Returns: a set view of the keys contained in this map

### method:navigableKeySet() [NONE]
- #### navigableKeySet
                                                                                                      public NavigableSet<K> navigableKeySet()
Description copied from interface: `NavigableMap` 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. If the map is modified while an iteration over the set is in progress (except through the iterator's own `remove` operation), the results of the iteration are undefined. 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. Specified by: `navigableKeySet` in interface `NavigableMap<K,V>` Returns: a navigable set view of the keys in this map Since: 1.6

### method:descendingKeySet() [NONE]
- #### descendingKeySet
                                                                                                      public NavigableSet<K> descendingKeySet()
Description copied from interface: `NavigableMap` 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. If the map is modified while an iteration over the set is in progress (except through the iterator's own `remove` operation), the results of the iteration are undefined. 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. Specified by: `descendingKeySet` in interface `NavigableMap<K,V>` Returns: a reverse order navigable set view of the keys in this map Since: 1.6

### method:values() [NONE]
- #### values
                                                                                                      public Collection<V> values()
Returns a `Collection` view of the values contained in this map. The collection's iterator returns the values in ascending order of the corresponding keys. The collection's spliterator is late-binding, fail-fast, and additionally reports `Spliterator.ORDERED` with an encounter order that is ascending order of the corresponding keys. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. If the map is modified while an iteration over the collection is in progress (except through the iterator's own `remove` operation), the results of the iteration are undefined. The collection supports element removal, which removes the corresponding mapping from the map, via the `Iterator.remove`, `Collection.remove`, `removeAll`, `retainAll` and `clear` operations. It does not support the `add` or `addAll` operations. Specified by: `values` in interface `Map<K,V>` Specified by: `values` in interface `SortedMap<K,V>` Overrides: `values` in class `AbstractMap<K,V>` Returns: a collection view of the values contained in this map

### method:entrySet() [NONE]
- #### entrySet
                                                                                                      public Set<Map.Entry<K,V>> entrySet()
Returns a `Set` view of the mappings contained in this map. The set's iterator returns the entries in ascending key order. The set's spliterator is late-binding, fail-fast, and additionally reports `Spliterator.SORTED` and `Spliterator.ORDERED` with an encounter order that is ascending key order. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own `remove` operation, or through the `setValue` operation on a map entry returned by the iterator) the results of the iteration are undefined. 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. Specified by: `entrySet` in interface `Map<K,V>` Specified by: `entrySet` in interface `SortedMap<K,V>` Returns: a set view of the mappings contained in this map, sorted in ascending key order

### method:descendingMap() [NONE]
- #### descendingMap
                                                                                                      public NavigableMap<K,V> descendingMap()
Description copied from interface: `NavigableMap` 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. If either map is modified while an iteration over a collection view of either map is in progress (except through the iterator's own `remove` operation), the results of the iteration are undefined. 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 Since: 1.6

### method:subMap(K,boolean,K,boolean) [NONE]
- #### subMap
                                                                                                      public NavigableMap<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 uses natural ordering, or its comparator 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 Since: 1.6

### method:headMap(K,boolean) [NONE]
- #### headMap
                                                                                                      public NavigableMap<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 uses natural ordering, or its comparator does not permit null keys `IllegalArgumentException` - if this map itself has a restricted range, and `toKey` lies outside the bounds of the range Since: 1.6

### method:tailMap(K,boolean) [NONE]
- #### tailMap
                                                                                                      public NavigableMap<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 uses natural ordering, or its comparator does not permit null keys `IllegalArgumentException` - if this map itself has a restricted range, and `fromKey` lies outside the bounds of the range Since: 1.6

### method:subMap(K,K) [NONE]
- #### subMap
                                                                                                      public SortedMap<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 uses natural ordering, or its comparator 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

### method:headMap(K) [NONE]
- #### headMap
                                                                                                      public SortedMap<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 uses natural ordering, or its comparator does not permit null keys `IllegalArgumentException` - if this map itself has a restricted range, and `toKey` lies outside the bounds of the range

### method:tailMap(K) [NONE]
- #### tailMap
                                                                                                      public SortedMap<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 uses natural ordering, or its comparator does not permit null keys `IllegalArgumentException` - if this map itself has a restricted range, and `fromKey` lies outside the bounds of the range