Java Enums

What is Enums

An enum type is a special data type which contains a fixed set of constants.

Java Enums can be thought of as classes which have a fixed set of constants (a variable that does not change). The Java enum constants are static and final implicitly. It is available since JDK 1.5.

Enums are used to create our own data type like classes. The enum data type (also known as Enumerated Data Type) is used to define an enum in Java. Unlike C/C++, enum in Java is more powerful. Here, we can define an enum either inside the class or outside the class.

Enum is short for “enumerations”, which means “specifically listed”.

Syntax

enum EnumName{

//group of constants

}

How to Access

EnumName myVar = EnumName .constant name;

Example

enum Level {
  LOW,
  MEDIUM,
  HIGH
}

public class Main { 
  public static void main(String[] args) { 
    Level myVar = Level.MEDIUM; 
    System.out.println(myVar); 

  } 
}

Enum inside a Class

You can also have an enum inside a class:

Example

public class Main { 
  enum Level {
    LOW,
    MEDIUM,
    HIGH
  }

  public static void main(String[] args) { 
    Level myVar = Level.MEDIUM; 
    System.out.println(myVar); 
  } 
}

//output 
MEDIUM

Enum in a Switch Statement

Enums are often used in switch statements to check for corresponding values:

Example

enum Level {
  LOW,
  MEDIUM,
  HIGH
}

public class Main {
  public static void main(String[] args) {
    Level myVar = Level.MEDIUM;

    switch(myVar) {
      case LOW:
        System.out.println("Low level");
        break;
      case MEDIUM:
         System.out.println("Medium level");
        break;
      case HIGH:
        System.out.println("High level");
        break;
    }
  }
}

//output 
Medium level