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Java EnumMap putAll() Method with Example

EnumMap Class putAll() method: Here, we are going to learn about the putAll() method of EnumMap Class with its syntax and example.
Submitted by Preeti Jain, on February 10, 2020

EnumMap Class putAll() method

• putAll() method is available in java.util package.
• putAll() method is used to replace all of the mappings from the given Map (map) to this map.
• putAll() 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.
• putAll() method may throw an exception at the time of replacing mappings.
  NullPointerException This exception may throw when the given parameter Map (map) is null exists or when one or more keys are null exists.

Syntax:

    public void putAll(Map map) ;

Parameter(s):

• Map map – represents the map that contains mappings to be saved in this map.

Return value:

The return type of this method is void, it returns nothing.

Example:

// Java program to demonstrate the example 
// of void putAll(Map map)  method of EnumMap

import java.util.*;

public class PutAllOfEnumMap {

    public enum Colors {
        RED,
        BLUE,
        PINK,
        YELLOW
    };

    public static void main(String[] args) {
        // We are creating two EnumMap objects
        EnumMap < Colors, String > em =
            new EnumMap < Colors, String > (Colors.class);

        EnumMap < Colors, String > copied_em =
            new EnumMap < Colors, String > (Colors.class);

        // By using put() method is to
        // add the linked values in an
        // EnumMap
        em.put(Colors.RED, "1");
        em.put(Colors.BLUE, "2");
        em.put(Colors.PINK, "3");
        em.put(Colors.YELLOW, "4");

        // Display EnumMap
        System.out.println("EnumMap (em) :" + em);

        // By using putAll() method isto
        // copies the mappings of the given EnumMap (em) 
        // and paste it into a copied EnumMap object 
        // (copied_em)
        copied_em.putAll(em);

        // Display Copied EnumMap
        System.out.println("copied_em.putAll(em): " + copied_em);
    }
}

Output

EnumMap (em) :{RED=1, BLUE=2, PINK=3, YELLOW=4}
copied_em.putAll(em): {RED=1, BLUE=2, PINK=3, YELLOW=4}