Java Development Notes
Short articles on Java patterns, best practices, and modern approaches
Thread Safety in Java: From Volatile to Atomic Types
Source: Production concurrency debugging, SonarQube rule java:S3077 Introduction Hook: Your application passes all unit tests, integration tests pass with flying colors, code review looks perfect. You deploy to production and suddenly - race conditions, null pointer exceptions under load, metrics showing wrong counts. The debugger shows nothing. Welcome to concurrency bugs. Why it matters: Concurrency bugs are among the hardest defects to diagnose in production. They manifest intermittently, disappear under debugger scrutiny, and only surface under real-world load. The root cause is almost always the same: shared mutable state accessed by multiple threads without proper synchronization. A single misunderstood volatile keyword can cause production outages. ...
Stop Writing Java Utility Classes the Old Way: Use Functional Interfaces Instead
Introduction Static utility classes spread business logic across your codebase and make it hard to test. Functional interfaces let you express domain rules as composable, testable functions that belong in your domain model. The Problem Business rules hidden in static utility classes: public class OrderValidationUtils { public static boolean isValidForProcessing(Order order) { return order.getTotalAmount() > 0 && order.getItems().size() > 0 && order.getCustomer() != null; } } // Usage scattered across the codebase if (OrderValidationUtils.isValidForProcessing(order)) { processOrder(order); } Problems: ...