Blog by Rahul Mittal

Introduction Congratulations! If you've followed this series from the beginning, you've travelled through one of the most remarkable evolutions in programming language history. This wasn't simply a journey from one Java version to another. It was the evolution of how enterprise software is designed. When Java 8 was released in 2014, most enterprise applications looked like this: Browser ↓ Monolithic…

Introduction If Java 8 gave us Streams and CompletableFuture, then Java 21 gives us something even more fundamental: A completely new way of thinking about concurrency. For over twenty years, Java developers learned the same rules: Threads are expensive. Never create one thread per request. Always use thread pools. Reuse threads. Asynchronous programming scales better. Reactive programming solves thread scalability.…

Introduction Most enterprise developers spend their days writing: Spring Boot REST APIs Database queries Kafka consumers REST clients Business validations Authentication Authorization Very little of this work is CPU intensive. Most enterprise applications spend their time waiting for: Database responses Network calls Cache lookups Message brokers So why did Oracle introduce the Vector API? The answer lies in a different…

Introduction If you've spent your career developing Spring Boot microservices, you may never have written a single line of C or C++. Yet every day your Java applications depend on native code. Think about a modern banking platform. Internet Banking │ ▼ API Gateway (Spring Boot) │ ┌──────────────────┼──────────────────┐ ▼ ▼ ▼ Account Service Payment Service Customer Service │ │ │…

Introduction The Java Collections Framework has been one of Java's greatest strengths since Java 1.2. Enterprise developers use collections everywhere: REST APIs Spring Boot applications Database queries Cache implementations Message processing Batch jobs Data transformation Stream processing Despite its maturity, the Collections Framework had one long-standing inconsistency. Some collections maintained insertion order. Others maintained sorted order. Others had no defined…

Introduction If you've followed this series from Java 8 to Java 17, you may have noticed something unusual. After Java 17, we suddenly started discussing Java 21. Naturally, many developers ask: What happened to Java 18? Was Java 19 skipped? Did Java 20 introduce anything important? Why do most companies migrate directly from Java 17 to Java 21? The answer…

Introduction One of the most common operations in object-oriented programming is determining an object's type before performing a specific action. Consider a payment processing system. Payment │ ┌──────────────┼──────────────┐ ▼ ▼ ▼ CreditCard UPI Payment NetBanking Every enterprise application eventually needs code like: Process different payment methods. Handle different event types. Validate different request objects. Execute workflow based on message type.…