Java TreeMap.firstEntry() example

Java TreeMap.firstEntry() example

By technicalkeeda, Views 344, Date 21-Feb-2018

In this java tutorial, You will learn how to use firstEntry() method of TreeMap class.The firstEntry() method is used to return a key-value mapping associated with the least key in this map, or null if the map is empty.

tags Java

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

syntax

public Map.Entry<K,V> firstEntry()

Returns

An entry with the least key, or null if this map is empty.

Java TreeMap firstEntry() example

  • Create TreeMap instance new TreeMap < Integer, String > ();
  • Add few elements in TreeMap e.g. students.put(1, "Pooja");
  • Print the TreeMap values.
  • students.firstEntry(); It will return first entry of TreeMap.
  • Print the first entry of TreeMap.
package com.technicalkeeda;

import java.util.TreeMap;

public class App {
    public static void main(String args[]) {

        TreeMap < Integer, String > students = new TreeMap < Integer, String > ();

        students.put(1, "Pooja");
        students.put(2, "Ajit");
        students.put(3, "Yashwant");
        students.put(4, "Aditi");

        System.out.println("TreeMap values:- " + students);

        System.out.println("First entry:- " + students.firstEntry());

    }
}

output

TreeMap values:- {1=Pooja, 2=Ajit, 3=Yashwant, 4=Aditi}
First entry:- 1=Pooja
Yashwant

Yashwant

Hi there! I am founder of technicalkeeda.com and programming enthusiast. My skills includes Java,J2EE, Spring Framework, Nodejs, PHP and lot more. If you have any idea that you would want me to develop? Lets connect: yashwantchavan[at][gmail.com]