lastKey() method

lastKey(): It returns the key from TreeMap which have the greatest value(Key having highest value). It returns null if TreeMap is empty.

import java.util.TreeMap;
class ExampleOfTreeMap
{
	public static void main(String arg[])
	{
		TreeMap<Integer, String> listOfNames = new TreeMap<Integer, String>();
		listOfNames.put(3, "C");
		listOfNames.put(1, "A");
		listOfNames.put(2, "D");
		listOfNames.put(6, "B");
		listOfNames.put(8, "B");
		
		// It return the greatest Key of TreeMap
		System.out.println("Greatest Key of TreeMap:"+listOfNames.lastKey());		
	}
}

Output: Greatest Key of TreeMap:8