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It is NavigatableMap implemetnation based on Re-Black tree concept.
It map is sorted according to the natural ordering of its keys, or by a Comparator provided at the time of creation.
Note that this implementation is not synchronized.

package collection.demos;

import java.util.Map;

import java.util.NavigableMap;

import java.util.TreeMap;

public class TreeMapDemo1 {

    public static void main(String[] args) {

        TreeMap<StringLong> phoneNumbers = new TreeMap<StringLong>();

        //Putting values in TreeMap






        System.out.println("Values : " + phoneNumbers);

        //Returning the first (lowest) key currently in this map.

        System.out.println("First Key : " + phoneNumbers.firstKey());

        //Returning the last (highest) key currently in this map.

        System.out.println("Last Key : " + phoneNumbers.lastKey());

        //Getting a key-value mapping associated with the least key in this map, or null if the map is empty.

        Map.Entry<StringLong> entry = phoneNumbers.firstEntry();

        System.out.println("firstEntry " + entry);

        //Getting a key-value mapping associated with the greatest key in this map, or null if the map is empty.

        entry = phoneNumbers.lastEntry();

        System.out.println("Last Entry " + entry);

        //Getting a key-value mapping associated with the greatest key strictly less than the given key, or null if there is no such key.

        entry = phoneNumbers.lowerEntry("Shoye");//Similler for lowerKey(K key) to get lower key

        System.out.println("lowerEntry of Shoye key : " + entry);

        //getting 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.

        entry = phoneNumbers.ceilingEntry("Abc");//Similler for lowerKey(K key) to get lower key

        System.out.println("ceilingEntry of Abc key : " + entry);

        //Getting a view of the portion of this map whose keys are less than (or equal to, if inclusive is true) toKey.

        NavigableMap<StringLong> headMap = phoneNumbers.headMap("Korp"true);

        System.out.println("Head Map " + headMap);

        //Getting a view of the portion of this map whose keys are greater than (or equal to, if inclusive is true) fromKey.

        NavigableMap<StringLong> tailMap = phoneNumbers.tailMap("Korp"true);

        System.out.println("Tail Map " + tailMap);

        //rest of fucntionalities are simillar to Map




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