Java TreeMap lastKey() Method Example

The firstKey() method of java.util.TreeMap returns the first (lowest) key currently in this map whereas lastKey() method returns the last (highest) key currently in this map.

Signature

public K lastKey()

This method returns the last (highest) key currently in this map. Thorws NoSuchElementException if this map is empty

Example

The following example shows the usage of java.util.TreeMap.lastKey() method.

import java.util.Map;
import java.util.Set;
import java.util.TreeMap;

public class LastKeyMethodTreeMapExample
{
    public static void main(String args[])
    {
        // create an empty TreeMap
        TreeMap<Integer,String>  treeMap1 = new TreeMap<Integer,String>();
        
        // use put() method to populate elements to the TreeMap
        treeMap1.put(2,"Element2");
        treeMap1.put(3,"Element3");
        treeMap1.put(1,"Element1");
        treeMap1.put(4,"Element4");
        treeMap1.put(5,"Element5");
        
        //get the entrySet of treeMap1
        Set<Map.Entry<Integer,String>> set1 = treeMap1.entrySet();.
        //Print the elements of treeMap1
        System.out.println("**Elements of treeMap1**");
        for (Map.Entry<Integer,String> me : set1) 
        {
            System.out.print(me.getKey() + ": ");
            System.out.println(me.getValue());
        }
        
        //Get the Last key of the Map
        System.out.println("First Key of treeMap1 : "+treeMap1.lastKey());
    }
}

Output

**Elements of treeMap1**
1: Element1
2: Element2
3: Element3
4: Element4
5: Element5
Last Key of treeMap1 : 5

Leave a Reply

Your email address will not be published. Required fields are marked *