Mastering Java Enums: A Beginner’s Guide to Enums in Java

Unlock the Power of Java Enums

What is a Java Enum?

In Java, an enumeration (or enum for short) is a special type that represents a fixed set of constant values. To declare an enum, we use the enum keyword. For instance, let’s create an enum called Size with four constant values: SMALL, MEDIUM, LARGE, and EXTRALARGE.

Accessing Enum Constants

To access these constant values, we can use the enum name. We can also create variables of the enum type, which can only be assigned one of the predefined values. For example, pizzaSize is a variable of the Size type, which can only be SMALL, MEDIUM, LARGE, or EXTRALARGE.

Using Enums with Switch Statements

Enums can be used with switch statements to execute specific code based on the enum value. In the following example, we create an enum type Size and a variable pizzaSize of the Size type. The switch statement then executes different code based on the value of pizzaSize.

Enum Classes in Java

In Java, enum types are actually special classes that were introduced in Java 5. Like regular classes, enum classes can include methods and fields. When we create an enum class, the compiler automatically creates instances (objects) of each enum constant. These instances are public, static, and final by default.

Methods of Java Enum Classes

Java enum classes come with several predefined methods that can be used to manipulate enum constants. These include:

• ordinal(): returns the position of an enum constant
• compareTo(): compares enum constants based on their ordinal value
• toString(): returns the string representation of an enum constant
• name(): returns the defined name of an enum constant in string form
• valueOf(): takes a string and returns an enum constant with the same name
• values(): returns an array of enum type containing all the enum constants

Why Use Java Enums?

Java enums were introduced to replace the use of int constants. By using enums, we can make our code more intuitive and type-safe. Enums ensure that a variable can only hold one of the predefined values, preventing errors and making our code more reliable.