What is a NavigableMap in Java?
Table of Contents
- 1 What is a NavigableMap in Java?
- 2 What is tailMap in Java?
- 3 Which method of NavigableMap returns the least key greater than or equal to the specified key?
- 4 What is LinkedHashMap in Java?
- 5 How do you get the first value from TreeMap?
- 6 What is SortedMap in Java?
- 7 What is difference between hash table and tree?
- 8 What is the difference between HashMap and LinkedHashMap?
- 9 What is navigablemap interface in Java?
- 10 What is navnavigablemap in Java 6?
The Java NavigableMap interface, java.util.NavigableMap , is a sub-interface of the. Java SortedMap interface. The NavigableMap interface has a few extensions to the SortedSet interface which makes it possible to navigate the keys and values stored in the map.
What is tailMap in Java?
tailMap(from_Key) method in Java is used to get a part or view of the map whose keys are greater than equal to the from_key in the parameter. Any changes made in one map will reflect the change in the other map.
Method Summary
| Modifier and Type | Method and Description |
|---|---|
| K | ceilingKey(K key) Returns the least key greater than or equal to the given key, or null if there is no such key. |
| NavigableSet | descendingKeySet() Returns a reverse order NavigableSet view of the keys contained in this map. |
What is the use of TreeMap in Java?
The TreeMap in Java is used to implement Map interface and NavigableMap along with the AbstractMap Class. 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.
What is difference between HashMap and TreeMap?
HashMap allows a single null key and multiple null values. TreeMap does not allow null keys but can have multiple null values. HashMap allows heterogeneous elements because it does not perform sorting on keys. TreeMap allows homogeneous values as a key because of sorting.
What is LinkedHashMap in Java?
A LinkedHashMap contains values based on the key. It implements the Map interface and extends the HashMap class. It contains only unique elements. It may have one null key and multiple null values. It is non-synchronized.
How do you get the first value from TreeMap?
To get first element, you have to sort the TreeMap based on user defined objects by using comparator object. You can include you own custom sorting logic with compare method. By passing comparator object to the TreeMap, you can sort the keys based on the logic provided inside the compare method.
What is SortedMap in Java?
A Map that further provides a total ordering on its keys. The map is ordered according to the natural ordering of its keys, or by a Comparator typically provided at sorted map creation time.
When should you use TreeMap?
appropriate use cases for treemaps Treemaps can work well if your data falls into this scenario: You want to visualize a part-to-whole relationship amongst a large number of categories. Precise comparisons between categories is not important. The data is hierarchical.
What is the difference between HashMap and LinkedHashMap in Java?
The Major Difference between the HashMap and LinkedHashMap is the ordering of the elements. The LinkedHashMap provides a way to order and trace the elements. The HashMap extends AbstractMap class and implements Map interface, whereas the LinkedHashMap extends HashMap class and implements Map interface.
What is difference between hash table and tree?
When you go beyond strings, hash tables and binary search trees make different requirements on the data type of the key: hash tables require a hash function (a function from the keys to the integers such that k1≡k2⟹h(k1)=h(k2), while binary search trees require a total order.
What is the difference between HashMap and LinkedHashMap?
NavigableMap Interface in Java with Example. NavigableMap is an extension of SortedMap which provides convenient navigation method like lowerKey, floorKey, ceilingKey and higherKey, and along with these popular navigation method it also provide ways to create a Sub Map from existing Map in Java e.g.
What are the methods of navigablemap?
The methods of the NavigableMap are given in the following table. Here, K – The type of the keys in the map. V – The type of values mapped in the map. 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.
What is the use of headmap in Java?
The headMap () method of NavigableMap interface in Java is used to return 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.
NavigableMap in Java 6 is an extension of SortedMap like TreeMap which provides convenient navigation methods like lowerKey, floorKey, ceilingKey, and higherKey.