Enum Map Example in Java

Introduction

Enum Map is a classic Java console program that demonstrates the concept with complete source code and sample output. The Collections Framework provides ArrayList, HashMap, HashSet and related data structures.

This tutorial walks through the program line by line, explains how the logic works, and highlights best practices you can apply in your own code.

Definition

EnumMap is a specialized Map implementation for use with enum type keys. All of the keys in an enum map must come from a single enum type. Enum maps are maintained in the natural order of their keys.

Syntax

EnumMap<enum-name, value-type> variable-name

EnumMap Example Program

import java.util.EnumMap;

public class EnumMapExample {

    enum Directions {
        NORTH, SOUTH, EAST, WEST
    }

    public static void main(String[] args) {
        EnumMap<Directions, String> map = new EnumMap<Directions, String>(Directions.class);
        map.put(Directions.NORTH, "North Direction");
        map.put(Directions.SOUTH, "South Direction");
        map.put(Directions.EAST, "East Direction");
        map.put(Directions.WEST, "West Direction");

        System.out.println("The values in EnumMap are : " + map);

        System.out.println("Size of EnumMap : " + map.size());
        System.out.println("Value in key : " + Directions.EAST + " is : " + map.get(Directions.EAST));
        System.out.println("Checking if the EnumMap contains key : " + Directions.NORTH + " : " + map.containsKey(Directions.NORTH));
        System.out.println("Checking if the EnumMap contains value South Direction : " + map.containsValue("South Direction"));

    }
}

Sample Output

The values in EnumMap are : {NORTH=North Direction, SOUTH=South Direction, EAST=East Direction, WEST=West Direction}
Size of EnumMap : 4
Value in key : EAST is : East Direction
Checking if the EnumMap contains key : NORTH : true
Checking if the EnumMap contains value South Direction : true

When to use

Use this enum map example when learning or revising core Java syntax.

How it works

1. Execution begins in the main method — the JVM calls this method when you run the class.

2. import java.util.EnumMap; imports a class used later in the program.

3. EnumMap<Directions, String> map = new EnumMap<Directions, String>(Directions.class); updates a variable used in the calculation or output.

4. A println / print call writes text to the console — part of the sample output below.

5. A println / print call writes text to the console — part of the sample output below.

6. A println / print call writes text to the console — part of the sample output below.

7. A println / print call writes text to the console — part of the sample output below.

8. A println / print call writes text to the console — part of the sample output below.

Best Practices

• Use meaningful variable and class names that describe their purpose.
• Compile and run the program locally — modify values to see how output changes.
• Read compiler errors carefully; they usually point to the exact line to fix.

Common Mistakes

• Copying code without understanding each line — practice by changing one statement at a time.
• Mismatching the public class name and the .java filename.
• Forgetting semicolons at the end of statements.