🌐 In this article, we will understand the enhanced switch, introduced in Java 13.

📌 What's new

Besides the usual way to create a switch in Java. Now you can use an arrow and yield for your switch cases. But you can also the return value from a switch case to a variable.

📌 Switch case with arrows

Traditional Switch

public class Main {
    public static void main(String[] args) {
        String fruit = "Mango";
        switch (fruit) {
            case "Mango":
                System.out.println("Sweet and refreshing");
                break;
            case "Banana":
                System.out.println("High-fiber");
                break;
            case "Apple":
                System.out.println("Antioxidant effects");
                break;
            case "Papaya":
                System.out.println("Digestive enzymes");
                break;
            default:
                System.out.println("Eat fruits, Be Healthy!");
        }
    }
}

Enhanced Switch

public class Main {
    public static void main(String[] args) {
        String fruit = "Mango";
        switch (fruit) {
            case "Mango" -> System.out.println("Sweet and refreshing");
            case "Banana" -> System.out.println("High-fiber");
            case "Apple" -> System.out.println("Antioxidant effects");
            case "Papaya" -> System.out.println("Digestive enzymes");
            default -> System.out.println("Eat fruits, Be Healthy!");
        }
    }
}

Output:-

Sweet and refreshing

Pretty Cool isn't it?

If you use an arrow instead of a double point “:”, then you do not have to add a “break;” in every Switch case to avoid fall-through through your Switch cases. If the variable “fruit” has the value “Mango”, then case 1 with the output “Sweet and refreshing” is displayed only. You do not need a “break” in this case.

📌 Switch can be used as an expression

Let’s have a look at a code snippet to understand these changes better. The yield keyword is used to return a value in a case arm that is a block of code.

public class Main {
    public static void main(String[] args) {
        String fruit = "Mango";
        String selectedFruit = switch (fruit) {
            case "Mango" -> {
                yield "Mango";
            }
            case "Banana" -> {
                yield "Banana";
            }
            case "Apple" -> {
                yield "Apple";
            }
            case "Papaya" -> {
                yield "Papaya";
            }
            default -> {
                yield "";   // Empty
            }
        };
        System.out.println("Selected Fruit is " + selectedFruit);
    }
}

Output:-

Selected Fruit is Mango

The switch can now be used as an expression. This means the switch can now return values based on our input. There is a slight change in switch syntax to accommodate this change. A switch block needs to be delimited by a semicolon. The yield keyword is used to return values. No break is required with the yield statement.

📌 Yield

Use of yield

public class Main {
    public static void main(String[] args) {
        String fruit = "Mango";
        String selectedFruit = switch (fruit) {
            case "Mango" -> {
                System.out.println("Sweet and refreshing");
                yield "Mango";
            }
            case "Banana" -> {
                System.out.println("High-fiber");
                yield "Banana";
            }
            case "Apple" -> {
                System.out.println("Antioxidant effects");
                yield "Apple";
            }
            case "Papaya" -> {
                System.out.println("Digestive enzymes");
                yield "Papaya";
            }
            default -> {
                System.out.println("Eat fruits, Be Healthy!");
                yield "";   // Empty
            }
        };
        System.out.println("Selected Fruit is " + selectedFruit);
    }
}

Output:-

Sweet and refreshing

Selected Fruit is Mango

The function “yield” can be used in a Switch statement to return a value in a switch case to a variable. We don’t need a break after yield as it automatically terminates the switch expression.

📌 Preview feature

You have to enable or add the command “ — enable-preview” in the project properties of your IDE. It does not work in some online compilers, as it is still in the experiment phase.

The enhanced switch in Java 13 provides several impressive features to the traditional switch.

Source: Enhancements for Switch Statement in Java 13

https://www.geeksforgeeks.org/enhancements-for-switch-statement-in-java-13/