EnumMap forEach(BiConsumer) in Java

forEach(BiConsumer): This method is available in java.util.EnumMap class of Java.

Syntax:

void java.util.Map.forEach(BiConsumer<? super K, ? super V> action)

This method performs the given action for each entry in this map until all entries have been processed or the action throws an exception.

Parameters: One parameter is required for this method.

action: The action to be performed for each entry.

Throws:

1. NullPointerException - if the specified action is null.

2. ConcurrentModificationException - if an entry is found to be removed during iteration.

Approach 1: When no exception

Java

import java.util.EnumMap;

public class EnumMapforEach {

    public enum Colour {
        RED, GREEN, YELLOW, ORANGE
    };

    public static void main(String[] args) {

        EnumMap<Colour, String> enumMap = 
                 new EnumMap<Colour, String>(Colour.class);

        enumMap.put(Colour.RED, "Red");
        enumMap.put(Colour.GREEN, "Green");

        enumMap.put(Colour.YELLOW, "Yellow");
        enumMap.put(Colour.ORANGE, "Orange");

        enumMap.forEach((key, value) ->
             System.out.println(key + "-" + value));

    }
}

Output:

RED-Red

GREEN-Green

YELLOW-Yellow

ORANGE-Orange

Approach 2: NullPointerException

Java

import java.util.EnumMap;

public class EnumMapforEach {

    public enum Colour {
        RED, GREEN, YELLOW, ORANGE
    };

    public static void main(String[] args) {

        EnumMap<Colour, String> enumMap = 
            new EnumMap<Colour, String>(Colour.class);

        enumMap.put(Colour.RED, "Red");
        enumMap.put(Colour.GREEN, "Green");

        enumMap.put(Colour.YELLOW, "Yellow");
        enumMap.put(Colour.ORANGE, "Orange");

        enumMap.forEach(null);

    }
}

Output:

Exception in thread "main" java.lang.NullPointerException
	at java.base/java.util.Objects.requireNonNull(Objects.java:208)
	at java.base/java.util.Map.forEach(Map.java:650)