How to Copy Key-Value Pairs from One TreeMap to Another in Java?

Last Updated : 06 Feb, 2024

In Java, a TreeMap is a Map implementation that stores key-value pairs in a red-black tree structure. It allows insertions and deletions of key-value pairs due to its tree implementation. These operations take O(log n) time on average.

In this article, we will be learning how to copy key-value pairs from one TreeMap to another in Java.

Syntax:

newTreeMap.putAll(originalTreeMap);

This will copy all the key-value pairs from originalTreeMap to newTreeMap.

Program to Copy Key-Value Pairs from One TreeMap to Another in Java

To copy key-value pairs from one TreeMap to another, we can use putAll() method. Below is the code implementation for this:

Java

// Java program to copy key-value pairs from one TreeMap to another using putAll() import java.util.TreeMap;  public class CopyTreeMap {     public static void main(String[] args)      {         // Create the course TreeMap         TreeMap<String, Integer> courseTreeMap = new TreeMap<>();         courseTreeMap.put("Core Java", 10000);         courseTreeMap.put("Spring Boot", 20000);         courseTreeMap.put("AWS", 25000);                  // Print the course TreeMap         System.out.println("Course TreeMap: " + courseTreeMap);          // Create the another TreeMap         TreeMap<String, Integer> newCourseTreeMap = new TreeMap<>();          // Copy key-value pairs using putAll() method         newCourseTreeMap.putAll(courseTreeMap);          // Print the newCourse TreeMap         System.out.println("New Course TreeMap: " + newCourseTreeMap);     } }

Output

Course TreeMap: {AWS=25000, Core Java=10000, Spring Boot=20000}  New Course TreeMap: {AWS=25000, Core Java=10000, Spring Boot=20000}