Java — Modern Java Switch Expressions (Java 14+) & Condition Pitfalls

public class Main {
    public static void main(String[] args) {
        String quarterMonth = "APRIL";

        System.out.println("=== Modern Java 14+ Switch Expressions ===");

        // 1. Switch Expression assigning directly to a variable with arrow syntax
        int fiscalQuarter = switch (quarterMonth) {
            case "JANUARY", "FEBRUARY", "MARCH"     -> 1;
            case "APRIL", "MAY", "JUNE"             -> 2;
            case "JULY", "AUGUST", "SEPTEMBER"      -> 3;
            case "OCTOBER", "NOVEMBER", "DECEMBER"  -> 4;
            default -> 0;
        };

        System.out.println("Month: " + quarterMonth + " belongs to Q" + fiscalQuarter);

        // 2. Multi-statement block using the 'yield' keyword
        String priorityLevel = "HIGH";
        int responseTimeHours = switch (priorityLevel) {
            case "CRITICAL" -> 1;
            case "HIGH"     -> {
                System.out.println("[Log] High-priority incident escalated to On-Call Engineer.");
                yield 4; // Returns 4 hours SLA
            }
            case "MEDIUM"   -> 12;
            case "LOW"      -> 24;
            default         -> {
                System.out.println("[Log] Unknown priority. Defaulting to standard SLA.");
                yield 48;
            }
        };

        System.out.println("Incident SLA Response Time: " + responseTimeHours + " Hours");
    }
}

=== Modern Java 14+ Switch Expressions ===
Month: APRIL belongs to Q2
[Log] High-priority incident escalated to On-Call Engineer.
Incident SLA Response Time: 4 Hours

public class OrderDiscountCalculator {
    public static void main(String[] args) {
        String customerTier = "GOLD";
        double orderAmount   = 5000.00;

        // Compute discount rate using Modern Switch Expression
        double discountRate = switch (customerTier) {
            case "VIP", "PLATINUM" -> 0.20; // 20% Discount
            case "GOLD"            -> 0.15; // 15% Discount
            case "SILVER"          -> 0.10; // 10% Discount
            case "BRONZE"          -> 0.05; // 5% Discount
            default                -> 0.00; // No Discount
        };

        double discountAmount = orderAmount * discountRate;
        double finalPayable   = orderAmount - discountAmount;

        System.out.println("=== E-Commerce Checkout Summary ===");
        System.out.printf("Customer Tier   : %s%n", customerTier);
        System.out.printf("Original Order  : ₹%,.2f%n", orderAmount);
        System.out.printf("Applied Discount: %.0f%%%n", (discountRate * 100));
        System.out.printf("Savings Amount  : ₹%,.2f%n", discountAmount);
        System.out.printf("Final Total Due : ₹%,.2f%n", finalPayable);
    }
}