Java Bean vs Spring Bean vs Function Bean in Spring

For years, we’ve accepted that running Java applications meant running on the JVM. But what if that assumption no longer holds? I just published a new article exploring how Spring Boot applications can be compiled into native executables using GraalVM Native Image—dramatically reducing startup time and memory usage, which is especially relevant in cloud and serverless environments. Native images are built ahead-of-time into standalone binaries, eliminating the need for a JVM at runtime and enabling faster startup and lower resource consumption. This is not just about performance—it’s about rethinking how we build and run Java in a world where every millisecond and megabyte has a cost. In the article, I walk through: - The real problem behind Java resource consumption in the cloud - The trade-offs between JVM (JIT) and AOT compilation - How Spring Boot AOT makes native compilation viable - A minimal working example using Gradle and modern Java If you’re building microservices, running in containers, or exploring serverless with Java, this might change how you think about your architecture. 👉 Read the full article: https://lnkd.in/dcAvBVTz Curious to hear your thoughts—are native images something you’re already using or still evaluating?

This is good news, but at the same time gives me the feeling that Spring Boot is playing catch up with Quarkus. Developers are the winners in all this, because they get to finally enjoy native images in their Spring Boot projects.

Coming from a Java + Spring Boot background, I’ve built and consumed REST APIs for years. Recently, while experimenting with FastAPI, I stumbled upon a subtle but very interesting difference in how request routing works—and it genuinely made me pause and think. Consider this scenario: In FastAPI, if you define routes like: /books/{book_title} /books/harry and you place the dynamic route first, a request to /books/harry will be handled by the dynamic path, not the static one. Why? 👉 FastAPI resolves routes in the order they are defined. The first matching route wins—even if a more specific route exists later. As a Java developer, this felt counter‑intuitive at first. In Spring Boot, the framework does things differently: Routes are not resolved by order Spring calculates path specificity A static route like /books/harry will always win over /books/{bookTitle}, regardless of how methods are ordered So the same API behaves differently across frameworks—not because one is wrong, but because of different design philosophies: FastAPI / Python → explicit, developer‑controlled, minimal magic Spring Boot / Java → convention‑driven, framework‑managed, intelligent dispatching 📌 Key takeaway for me: When working with FastAPI, route ordering matters. Static routes should be defined before dynamic ones to avoid unexpected behavior. This small difference reinforced something important: Understanding the framework internals matters just as much as knowing the language. Learning new stacks like FastAPI as a Java developer has been both refreshing and humbling—and these nuances are what make the journey exciting. Curious to hear from others who’ve switched between ecosystems—what surprised you the most? #Java #SpringBoot #FastAPI #Python #BackendDevelopment #RESTAPI #LearningJourney #SoftwareEngineering

📅 Day 82 – AI Powered Java Full Stack Course 🚀 📚 Course Update: Spring Framework Deep Dive 🌱 In today’s learning journey, I explored the powerful Spring Framework, one of the most widely used frameworks in Java development. 🔹 Spring vs ORM Frameworks Spring is a complete ecosystem, whereas ORM tools like Hibernate mainly focus on database interaction. 🔹 Spring vs Spring Boot Spring Boot simplifies Spring by reducing configuration and promoting annotation-based development. 💡 Key Spring Modules I Learned: 🔸 Spring Core (Context Module) The foundation of Spring – handles IoC (Inversion of Control) and Dependency Injection. 🔸 Spring JDBC Simplifies database operations by combining Java + SQL with framework support. 🔸 Spring ORM Integrates ORM frameworks like Hibernate. 🔸 Spring JPA An advanced ORM approach with more abstraction, widely used in modern applications. 🔸 Spring MVC Implements Model-View-Controller architecture: • Model → POJOs • View → JSP • Controller → Servlets 🔸 Spring REST Used to build RESTful APIs using JSON/XML (modern replacement for SOAP-based services). 🔸 Spring AOP (Aspect-Oriented Programming) Handles cross-cutting concerns like logging and security. 🔸 Spring Security 🔐 Provides authentication & authorization (JWT, role-based access). 🔸 Spring Actuator 📊 Monitors application health and performance (/health, /metrics, etc.) 🔸 Spring AI 🤖 Used for building AI-powered applications like chatbots using LLMs. 🔸 Spring Boot 🚀 A wrapper over Spring that simplifies setup, configuration, and development. 💭 Key Takeaway: Spring is not just a framework — it's a complete ecosystem that helps build scalable, secure, and production-ready applications. #Day82 #Java #SpringFramework #SpringBoot #BackendDevelopment #FullStackDeveloper #LearningJourney #AI #Tech

Records in Java — Say Goodbye to Boilerplate Code Writing simple data classes in Java used to mean creating: fields constructors getters equals() hashCode() toString() A lot of code… just to store data. With Records (introduced in Java), Java made this much simpler. Instead of writing this: class Person { private final String name; private final int age; public Person(String name, int age) { this.name = name; this.age = age; } public String getName() { return name; } public int getAge() { return age; } } You can simply write: record Person(String name, int age) {} And Java automatically generates: 1. Constructor 2. Getter methods (name(), age()) 3. equals() 4. hashCode() 5. toString() Why Records matter? 1. Less boilerplate code 2. Immutable by default 3. Cleaner and more readable code 4. Perfect for DTOs, API requests/responses, and model classes Example: record Employee(String name, String department, double salary) {} Usage: Employee emp = new Employee("John", "Engineering", 90000); System.out.println(emp.name()); Records become even more powerful with modern Java features like Sealed Classes: sealed interface Shape permits Circle, Rectangle {} record Circle(double radius) implements Shape {} record Rectangle(double length, double width) implements Shape {} Modern Java is getting cleaner, safer, and more expressive. In one line: Records = Less code, more clarity. #Java #Java17 #JavaDeveloper #BackendDevelopment #Programming #SoftwareEngineering #Coding

Java roadmaps often fail for one simple reason: they teach tools, but not order. What usually gets developers stuck is not a lack of effort. It is learning things out of sequence. Jumping into Spring too early, skipping SQL, or treating frameworks and tooling as knowledge creates gaps that only become obvious later, once the work starts looking more like real systems and less like tutorials. A more useful Java roadmap for 2026 starts with the foundation. First comes core Java: syntax, control flow, arrays, classes, objects, exceptions, package structure, classpath, and the basic toolchain. Then the standard library: collections, generics, lambdas, streams, Optional, records, file I/O, StringBuilder, Math, and the Date/Time API. This is the layer that turns Java from something you can write into something you can reason about. After that come the everyday tools that shape real work: Git, GitHub or GitLab, IntelliJ IDEA, debugging, refactoring, Maven, and Gradle. Then comes one of the most important sequencing decisions in the whole roadmap: data persistence. Learn SQL and JDBC before Hibernate or JPA. If you skip the database layer and go straight to ORM, you end up using abstractions you do not really understand. Only then does the enterprise stack start to land properly. Spring Web, Spring Data, Spring Security, and dependency injection make much more sense once the lower layers are already in place. After that, testing and code quality become essential: unit tests, integration tests, mocking, faking, and eventually more advanced approaches such as mutation testing, property-based testing, and BDD. From there, the roadmap moves into deployment and infrastructure with Docker, CI/CD, GitHub Actions, and Jenkins, and ends with concurrency and java.util.concurrent. That order matters more than most people think. That is the real roadmap in one sentence: not learning everything, but learning the right things in the right sequence. If you prefer a video walkthrough, Pasha Finkelshteyn covers the roadmap here: https://hubs.li/Q04clKcF0 Roadmap PDF: https://hubs.li/Q04clFF90

🤔6 Ways to Create Objects in Java — and what actually matters in real projects When we start Java, we learn only one way to create objects: using new. But later we discover there are multiple ways — which gets confusing quickly. 1️⃣ Using the new keyword Student s = new Student(); This is the normal and most common way. Pros✅ · Simple and fast · Easy to understand · Compile-time safety Cons❌ · Creates tight coupling between classes › Industry usage: Used everywhere. This is the default way in day-to-day coding. 2️⃣Using Class.newInstance() Old reflection method. Pros✅ · Historical method Cons❌ · Deprecated since Java 9 · Should not be used anymore › Industry usage: Obsolete. 3️⃣Using Reflection (Constructor.newInstance()) Frameworks can create objects dynamically at runtime using reflection. Pros✅ · Can create objects dynamically · Useful when class name is not known beforehand Cons❌ · Slower than new · Complex and exception-heavy · Harder to debug › Industry usage: Used heavily inside frameworks like Spring and Hibernate, not in daily coding. 4️⃣ Using Deserialization Objects recreated from stored data. Pros✅ · Useful for caching and distributed systems · Helps in data transfer between systems Cons❌ · Security risks if misused · Rare in beginner-level projects › Industry usage: Used in backend infrastructure and large systems. 5️⃣ Using clone() Creates a copy of an existing object. Pros✅ · Fast copying of objects Cons❌ · Confusing (shallow vs deep copy) · Considered bad practice today › Industry usage: Rarely used now. 6️⃣Dependency Injection (DI) Frameworks (like Spring Boot) create objects and give them to your classes automatically. Example idea: Instead of creating objects manually, the framework injects them for you. Pros✅ · Loose coupling · Easier testing · Better architecture for big apps Cons❌ · Requires framework setup · Can feel confusing initially › Industry usage: This is the most used approach in modern backend development. 🚀 Final Reality Check Used daily: · new keyword · Dependency Injection (Spring Boot) Used internally by frameworks: · Reflection · Deserialization Avoid: · clone() · Class.newInstance() #Java #Programming #SpringBoot #BackendDevelopment #LearningJourney

Most developers learn Serialization in Java using Serializable — but that’s not how modern systems actually work. Serialization is simply converting an object into a format that can be stored or transferred, and deserialization is the reverse. Traditional approach in Java: - Serializable (marker interface) - ObjectOutputStream / ObjectInputStream This works, but has major drawbacks: - Not human-readable - Tight coupling between classes - Slower performance - Security concerns during deserialization Because of this, native Java serialization is rarely used in production today. Modern backend systems rely on different approaches: - JSON using libraries like and - Protobuf for high-performance communication - Avro for schema-based messaging systems - Kryo for faster serialization in specific use cases These approaches are: - Language-independent - Faster and more efficient - Easier to debug and maintain In , serialization and deserialization are handled automatically. When a controller returns an object, it is converted to JSON. When a request contains JSON, it is converted back into a Java object. Under the hood, this is handled by Jackson using ObjectMapper, which performs object-to-JSON and JSON-to-object conversion seamlessly. In microservices, serialization is used everywhere: - Service-to-service communication (REST/gRPC) - Messaging systems like Kafka or RabbitMQ - Caching systems like Redis Typical flow: Service A → JSON → HTTP → Service B Some common interview questions around this topic: Why is Serializable called a marker interface? It does not have methods; it simply signals the JVM that the class can be serialized. Why is native Java serialization avoided in microservices? Because of tight coupling, performance issues, and security risks. What is serialVersionUID? It is used for version control during deserialization. What happens if a field is marked transient? That field will not be serialized. How does Spring Boot handle serialization automatically? Using HttpMessageConverters with Jackson internally. Key takeaway: Understanding Serializable is important for fundamentals, but real-world systems rely on JSON or binary formats like Protobuf. If you are working with Spring Boot or microservices, this is a core concept you should be comfortable with. #Java #SpringBoot #Microservices #BackendDevelopment #SystemDesign

Java Reflection: The "Backdoor" Frameworks Use to See Your Private Code Ever wondered how Spring magically injects dependencies into your private fields? Or how Hibernate reads your data without a single getter? Welcome to the Reflection API—the JVM’s ultimate "skeleton key." 🗝️ In standard Java, private means private. It’s the cornerstone of encapsulation. But frameworks operate on a different level. They don't just execute your code; they inspect its blueprint. 🛠️ The 3-Step "Heist" Introspection: The framework grabs the Class object—a mirror of your code. Discovery: It uses getDeclaredFields() to find every field, ignoring visibility rules. The Override: The magic command field.setAccessible(true) tells the JVM to look the other way, bypassing access checks entirely. ⚖️ The Trade-off While Reflection is a superpower for building flexible frameworks, it comes with a "tax": Performance: It’s significantly slower than direct calls because the JVM can’t optimize it as easily. Security: Modern Java (post-v9) has started tightening the screws with the Module System, requiring you to explicitly "open" packages to allow this level of deep inspection. Reflection turns your compiled code into a searchable database. It’s the reason we can use annotations like @Autowired or @Entity to handle the heavy lifting while we focus on business logic. What’s the trickiest use of Reflection you’ve encountered in a production codebase? 👇 #Java #JVM #BackendDevelopment #SoftwareEngineering #SpringFramework #SystemDesign #CodingTips #TheBytecodePhantom

Written by Mike LaSpina published on Friends of OpenJDK (Foojay.io), learn CQRS in Java where he'll dive into separating reads and writes clealy. What you'll learn: - How the MongoDB Spring repository can be used to abstract MongoDB operations - Separating Reads and Writes in your application - How separating these can make schema design changes easier - Why you should avoid save() and saveAll() functions in Spring Read it here 👉 https://lnkd.in/gs8pnGpk #mongodb #java #nosql #database