Home » Java programming language

Java TreeMap lastKey() Method with Example

TreeMap Class lastKey() method: Here, we are going to learn about the lastKey() method of TreeMap Class with its syntax and example.
Submitted by Preeti Jain, on February 29, 2020

TreeMap Class lastKey() method

• lastKey() method is available in java.util package.
• lastKey() method is used to return the last highest key element value exists in this TreeMap.
• lastKey() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• lastKey() method may throw an exception at the time of returning the last highest key-value element.
  NoSuchElementException: This exception may throw when this TreeMap is blank.

Syntax:

    public Key lastKey();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of the method is Key, it retrieves the last higest key element exists in this TreeMap.

Example:

// Java program to demonstrate the example 
// of Key lastKey() method of TreeMap 

import java.util.*;

public class LastKeyOfTreeMap {
    public static void main(String[] args) {
        // Instantiates TreeMap
        TreeMap < Integer, String > tm = new TreeMap < Integer, String > ();

        // By using put() method is
        // to put the key-value pairs in
        // treemap tm
        tm.put(1, "C");
        tm.put(4, "C++");
        tm.put(3, "Java");
        tm.put(2, "Php");

        // Display TreeMap tm
        System.out.println("tm: " + tm);

        // By using lastKey() method is
        // used to return the key element
        // linked with the largest key element 
        // value i.e. 4
        // Display Returned Key Element
        System.out.println("tm.lastKey(): " + tm.lastKey());
    }
}

Output

tm: {1=C, 2=Php, 3=Java, 4=C++}
tm.lastKey(): 4