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Building Strong and adaptable Microservices with Java and Spring While building robust and scalable microservices can seem complex, understanding essential concepts empowers you for success. This post explores crucial elements for designing reliable distributed systems using Java and Spring frameworks. 𝗨𝗻𝗶𝘃𝗲𝗿𝘀𝗮𝗹 𝗣𝗿𝗶𝗻𝗰𝗶𝗽𝗹𝗲𝘀 𝗳𝗼𝗿 𝗕𝘂𝗶𝗹𝗱𝗶𝗻𝗴 𝗗𝗶𝘀𝘁𝗿𝗶𝗯𝘂𝘁𝗲𝗱 𝗦𝘆𝘀𝘁𝗲𝗺𝘀: The core principles of planning for failure, instrumentation, and automation are crucial across different technologies. While this specific implementation focuses on Java, these learnings are generally applicable when architecting distributed systems with other languages and frameworks as well. 𝗘𝘀𝘀𝗲𝗻𝘁𝗶𝗮𝗹 𝗖𝗼𝗺𝗽𝗼𝗻𝗲𝗻𝘁𝘀 𝗳𝗼𝗿 𝗠𝗶𝗰𝗿𝗼𝘀𝗲𝗿𝘃𝗶𝗰𝗲𝘀 𝗔𝗿𝗰𝗵𝗶𝘁𝗲𝗰𝘁𝘂𝗿𝗲: A typical microservices architecture involves: Multiple Microservices (MS) communicating via APIs: Services interact through well-defined Application Programming Interfaces (APIs). API Gateway for routing and security: An API Gateway acts as a single entry point, managing traffic routing and security for the microservices. Load Balancer for traffic management: A Load Balancer distributes incoming traffic efficiently across various service instances. Service Discovery for finding MS instances: Service Discovery helps locate and connect to specific microservices within the distributed system. Fault Tolerance with retries, circuit breakers etc.: Strategies like retries and circuit breakers ensure system resilience by handling failures gracefully. Distributed Tracing to monitor requests: Distributed tracing allows tracking requests across different microservices for better monitoring and debugging. Message Queues for asynchronous tasks: Message queues enable asynchronous communication, decoupling tasks and improving performance. Centralized Logging for debugging: Centralized logging simplifies troubleshooting by aggregating logs from all services in one place. Database per service (optional): Each microservice can have its own database for data ownership and isolation. CI/CD pipelines for rapid delivery: Continuous Integration (CI) and Continuous Delivery (CD) pipelines automate building, testing, and deploying microservices efficiently. 𝗟𝗲𝘃𝗲𝗿𝗮𝗴𝗶𝗻𝗴 𝗦𝗽𝗿𝗶𝗻𝗴 𝗙𝗿𝗮𝗺𝗲𝘄𝗼𝗿𝗸𝘀 𝗳𝗼𝗿 𝗘𝗳𝗳𝗶𝗰𝗶𝗲𝗻𝘁 𝗜𝗺𝗽𝗹𝗲𝗺𝗲𝗻𝘁𝗮𝘁𝗶𝗼𝗻: Frameworks like Spring Boot, Spring Cloud, and Resilience4j streamline the implementation of: Service Registration with Eureka Declarative REST APIs Client-Side Load Balancing with Ribbon Circuit Breakers with Hystrix Distributed Tracing with Sleuth + Zipkin 𝗞𝗲𝘆 𝗧𝗮𝗸𝗲𝗮𝘄𝗮𝘆𝘀 𝗳𝗼𝗿 𝗕𝘂𝗶𝗹𝗱𝗶𝗻𝗴 𝗥𝗼𝗯𝘂𝘀𝘁 𝗠𝗶𝗰𝗿𝗼𝘀𝗲𝗿𝘃𝗶𝗰𝗲𝘀: Adopt a services-first approach Plan for failure Instrument everything Automate deployment

Hey Java Juniors, are you REALLY Backend-ready in 2025? Mastering Java is just a Beginning! Also Focus on these👇 - Document your APIs with Swagger, shows professionalism. - Use JWT + Refresh Tokens, go beyond basic login. - Profile your code with VisualVM – learn memory + CPU insights. - Test with Testcontainers – real DBs > mocks. - Master Maven/Gradle basics – not just clean install. - Build real projects – CRUD is not enough. Add roles, tokens, error handling. - Read production code – reverse-engineer open-source Spring Boot apps. - Learn logs well – SLF4J, log levels, and tracing = backend debugging gold. - Understand layered architecture – Controller, Service, Repo. - Write unit + integration tests – use JUnit + Mockito smartly. Tip: Learn by building projects. Even small ones with REST APIs, JWT auth, and a database will set you apart! 🔥What would you add to this list? Connect Sabari Balaji for Tech Insights 💡 #JavaDeveloper #BackendDevelopment #SpringBoot #Microservices #TechSkills #DeveloperJourney

Only for backend engineers: ☕ Java: - OOPs & SOLID principles. - Collections Framework: Deep dive into HashMap, List vs Set, and their internal workings. - Java 8 Features: Streams, Lambdas, Optional, Functional interfaces. - Multithreading: Lifecycle, synchronized, volatile, and ExecutorService. - Exception Handling: Design custom exceptions, manage try-catch-finally effectively. - Memory Management: Stack vs Heap, Garbage Collection. 🌱 3. Spring Boot - Core Annotations: Master the usage of @RestController, @Service, @Repository, etc. - Spring Internals: Learn about starters, application.properties, and auto-configuration. - JPA & Hibernate: Mapping entities, @Transactional, lazy vs eager fetching. Error Handling: Implement @ControllerAdvice and @ExceptionHandler for centralized error handling. - RESTful APIs: Create REST APIs with CRUD operations, use @Valid, DTOs, and proper HTTP status codes. - Security Basics: Implement JWT authentication and role-based authorization. Testing: Use @WebMvcTest, @DataJpaTest, and Mockito for testing controllers and repositories. 🏗️ 4. Low-Level Design (LLD) - Focus on building scalable, maintainable, and clean software designs: - Class-Based Design: Design scenarios like Parking Lot, BookMyShow, and similar use cases. - Design Patterns: Learn core patterns such as Singleton, Strategy, Factory, Observer. - SOLID Principles & Clean Architecture: Aim for maintainable code with proper separation of concerns. - UML Diagrams: Use UML to showcase your design thinking process. 🏢 5. High-Level Design (HLD) - System Thinking: Focus on scalability, fault tolerance, and handling high availability. - Key Concepts: Load Balancers, Redis, Kafka, SQL vs NoSQL databases. - System Design Scenarios: Work through designs like URL Shortener, WhatsApp, Instagram, Rate Limiter. - API & DB Design: Understand sharding, partitioning, and rate-limiting strategies. - Trade-offs: Be prepared to discuss design trade-offs and justify your decisions. Resources: Spring Boot from Basics to Advanced (All Videos are in English) https://lnkd.in/gz2A5ih2 High Level Design from Basics to Advanced (Some Initial Videos are in Hindi, rest in English) https://lnkd.in/d8eDwYVA Low Level Design from Basics to Advanced (Some Initial Videos are in Hindi, rest in English) https://lnkd.in/dJkgzKxf JAVA from Basics to Advanced (All Videos are in English) https://lnkd.in/dUNA6vsU #softwareengineers

Writing Clean Microservices with Java (Spring Boot) Over the past few years, I’ve worked on Java/Spring Boot projects using microservice architecture. One thing that’s become very clear: your project structure can make or break your codebase. Here’s what I’ve found to be the most effective structure for building scalable, maintainable microservices with Spring Boot: Recommended Folder Structure check the image below Modular Design (DDD-ish for Microservices) Each microservice should own its own database Services communicate via REST, gRPC, or messaging (Kafka/RabbitMQ) Handle authentication centrally (e.g., via an Auth service with JWT) Keep services independently deployable 🧠 Best Practices ✅ Use DTOs to decouple APIs from domain models ✅ Avoid direct communication with other DBs — always use API or messaging ✅ Keep services small, focused, and self-contained ✅ Centralize configs with Spring Cloud Config or Consul ✅ Use OpenAPI (Swagger)Or Postman for API documentation ✅ Write integration & contract tests

Spring Framework’s flexibility comes from its modular design. Discover the building blocks that make Spring the powerhouse it is today. Spring consists of about 20 base modules which form the backbone of the Spring Framework: 𝘀𝗽𝗿𝗶𝗻𝗴-𝗰𝗼𝗿𝗲: Contains the fundamental parts and the core utilities other spring modules use. 𝘀𝗽𝗿𝗶𝗻𝗴-𝗯𝗲𝗮𝗻𝘀: Provides support for beans. Beans are objects managed by the IoC (Inversion of Control) Container. 𝘀𝗽𝗿𝗶𝗻𝗴-𝗰𝗼𝗻𝘁𝗲𝘅𝘁: The spring-context and spring-beans modules provide the basis for the IoC container and Dependency Injection and also responsible for managing the beans. 𝘀𝗽𝗿𝗶𝗻𝗴-𝗰𝗼𝗻𝘁𝗲𝘅𝘁-𝘀𝘂𝗽𝗽𝗼𝗿𝘁: Handles classes for integrating common third-party libraries into a Spring application context. 𝘀𝗽𝗿𝗶𝗻𝗴-𝗲𝘅𝗽𝗿𝗲𝘀𝘀𝗶𝗼𝗻: Provides the Spring Expression Language (SpEL) which is an expression language that supports querying and manipulating an object graph at runtime. 𝘀𝗽𝗿𝗶𝗻𝗴-𝗮𝗼𝗽: Enables modularization by separating cross-cutting concerns (like logging, and transaction management) into distinct aspects that can be applied across multiple classes. 𝘀𝗽𝗿𝗶𝗻𝗴-𝗮𝘀𝗽𝗲𝗰𝘁𝘀: Provides the integration mechanisms for AspectJ based aspects. 𝘀𝗽𝗿𝗶𝗻𝗴-𝗶𝗻𝘀𝘁𝗿𝘂𝗺𝗲𝗻𝘁: Provides class instrumentation and classloader implementations for application servers, enabling features like hot swapping. 𝘀𝗽𝗿𝗶𝗻𝗴-𝗶𝗻𝘀𝘁𝗿𝘂𝗺𝗲𝗻𝘁-𝘁𝗼𝗺𝗰𝗮𝘁: Provides an extension of Tomcat's default class loader, enabling instrumentation of loaded classes 𝘀𝗽𝗿𝗶𝗻𝗴-𝗺𝗲𝘀𝘀𝗮𝗴𝗶𝗻𝗴: Provides support for messaging architectures and protocols. 𝘀𝗽𝗿𝗶𝗻𝗴-𝗷𝗺𝘀: Provides support for Java Messaging Serice (JMS) features. 𝘀𝗽𝗿𝗶𝗻𝗴-𝗷𝗱𝗯𝗰: Provides an abstraction layer for JDBC which handles resource management, exception handling, and the execution of SQL queries. 𝘀𝗽𝗿𝗶𝗻𝗴-𝗼𝗿𝗺: Provides integration layers for object-relational mapping APIs, including JPA, JDO, and Hibernate. 𝘀𝗽𝗿𝗶𝗻𝗴-𝗼𝘅𝗺: Provides an abstraction layer that supports Object/XML mapping implementations. 𝘀𝗽𝗿𝗶𝗻𝗴-𝘁𝘅: Provides programmatic and declarative transaction management capabilities to Spring. 𝘀𝗽𝗿𝗶𝗻𝗴-𝘄𝗲𝗯: Provides essential features for building web applications integration with servlets and web contexts. 𝘀𝗽𝗿𝗶𝗻𝗴-𝘄𝗲𝗯𝗺𝘃𝗰: Contains Spring’s model-view-controller (MVC) and REST Web Services implementation for web applications. 𝘀𝗽𝗿𝗶𝗻𝗴-𝘄𝗲𝗯𝘀𝗼𝗰𝗸𝗲𝘁: Provides support for WebSocket, SockJS, and STOMP messaging support. 𝘀𝗽𝗿𝗶𝗻𝗴-𝘄𝗲𝗯𝗺𝘃𝗰-𝗽𝗼𝗿𝘁𝗹𝗲𝘁: Provides the MVC implementation for the Portlet environment. 𝘀𝗽𝗿𝗶𝗻𝗴-𝘁𝗲𝘀𝘁: Provides support for the unit testing and integration testing for Spring components with JUnit/TestNG and Mockito. Whether you're building a simple web app or a complex enterprise system, Spring's got your back. Follow Lahiru Liyanapathirana for more content like this.

If you’re building Spring Boot applications and your project is getting messy… It’s not a framework problem. It’s a structure problem. This image perfectly explains how a clean Spring Boot architecture should look below👇 🟢 Controller – Entry Point Handles HTTP requests, validates DTOs, and delegates work to services. 👉 Rule: No business logic here. 🔵 Service – Business Logic This is the brain of your application. Contains domain rules, transactions, workflows, and policies. 👉 If it changes business behavior, it belongs here. 🟣 Repository – Persistence Layer Responsible for database communication using JPA, Hibernate, JDBC, or external APIs. 👉 Only data access. Nothing more. 🟢 Model / Entity – Domain Representation Represents your core business objects. Keep them simple, consistent, and valid. 🟠 DTO – API Contract Never expose entities directly. DTOs protect internal changes and maintain API stability. 🟢 Config – Configuration Layer Handles Security, Beans, Infrastructure setup. 🔴 Exception Handling – Global Errors Centralized error handling makes your application predictable and clean. ✅ Why This Works ✔ Clear separation of concerns ✔ Easier unit testing ✔ Faster debugging ✔ Safer refactoring ✔ Microservices-ready architecture A clean architecture today saves you from production headaches tomorrow. 💬 How do you structure your Spring Boot projects — layered or feature-based? #SpringBoot #Java #BackendDevelopment #Microservices #SoftwareArchitecture #CleanCode #FullStackDeveloper

𝗪𝗵𝘆 𝗬𝗼𝘂𝗿 𝗦𝗽𝗿𝗶𝗻𝗴 𝗕𝗼𝗼𝘁 𝗣𝗿𝗼𝗷𝗲𝗰𝘁 𝗠𝗶𝗴𝗵𝘁 𝗕𝗲 𝗦𝗹𝗼𝘄𝗲𝗿 (𝗮𝗻𝗱 𝗛𝗮𝗿𝗱𝗲𝗿 𝘁𝗼 𝗠𝗮𝗶𝗻𝘁𝗮𝗶𝗻) 𝗧𝗵𝗮𝗻 𝗬𝗼𝘂 𝗧𝗵𝗶𝗻𝗸 Over the years, I’ve seen multiple Java and Spring Boot upgrades reshape how we build and maintain enterprise applications. Choosing the right combination of #Java and #SpringBoot versions has a direct impact on stability, performance, and the long-term sustainability of your system. 𝗝𝗮𝘃𝗮 𝗩𝗲𝗿𝘀𝗶𝗼𝗻𝘀 𝗢𝘃𝗲𝗿𝘃𝗶𝗲𝘄  • 𝗝𝗮𝘃𝗮 𝟴 (𝟮𝟬𝟭𝟰): Introduced 𝗹𝗮𝗺𝗯𝗱𝗮𝘀, 𝘀𝘁𝗿𝗲𝗮𝗺𝘀, 𝗮𝗻𝗱 𝗳𝘂𝗻𝗰𝘁𝗶𝗼𝗻𝗮𝗹 𝗽𝗿𝗼𝗴𝗿𝗮𝗺𝗺𝗶𝗻𝗴 𝗰𝗼𝗻𝘀𝘁𝗿𝘂𝗰𝘁𝘀. It became the standard for many years and still runs in a large number of production systems.  • 𝗝𝗮𝘃𝗮 𝟭𝟭 (𝟮𝟬𝟭𝟴): Brought the new HTTP client API, local variable type inference (var), and removed several deprecated modules.  • 𝗝𝗮𝘃𝗮 𝟭𝟳 (𝟮𝟬𝟮𝟭): Long-term support version with sealed classes, pattern matching, and major JVM performance improvements.  • 𝗝𝗮𝘃𝗮 𝟮𝟭 (𝟮𝟬𝟮𝟯): Added virtual threads, record patterns, and string templates -all aimed at improving concurrency and developer productivity. From a practical standpoint, 𝗝𝗮𝘃𝗮 𝟭𝟳 𝗮𝗻𝗱 𝗝𝗮𝘃𝗮 𝟮𝟭 are the most suitable for 𝗺𝗼𝗱𝗲𝗿𝗻 𝗺𝗶𝗰𝗿𝗼𝘀𝗲𝗿𝘃𝗶𝗰𝗲 𝗮𝗻𝗱 𝗰𝗹𝗼𝘂𝗱-𝗻𝗮𝘁𝗶𝘃𝗲 𝗮𝗽𝗽𝗹𝗶𝗰𝗮𝘁𝗶𝗼𝗻𝘀. 𝗦𝗽𝗿𝗶𝗻𝗴 𝗕𝗼𝗼𝘁 𝗩𝗲𝗿𝘀𝗶𝗼𝗻𝘀 𝗮𝗻𝗱 𝗖𝗼𝗺𝗽𝗮𝘁𝗶𝗯𝗶𝗹𝗶𝘁𝘆  • 𝗦𝗽𝗿𝗶𝗻𝗴 𝗕𝗼𝗼𝘁 𝟮.𝟱 𝘁𝗼 𝟮.𝟳: 𝗦𝘂𝗽𝗽𝗼𝗿𝘁𝘀 𝗝𝗮𝘃𝗮 𝟴 𝘁𝗼 𝟭𝟳. A good fit for existing systems that are not ready to move to Jakarta EE 9+.  • 𝗦𝗽𝗿𝗶𝗻𝗴 𝗕𝗼𝗼𝘁 𝟯.𝘅: 𝗥𝗲𝗾𝘂𝗶𝗿𝗲𝘀 𝗝𝗮𝘃𝗮 𝟭𝟳 𝗼𝗿 𝗵𝗶𝗴𝗵𝗲𝗿. Built on Spring Framework 6, with native support for Jakarta EE 9+, AOT processing, and GraalVM integration. 𝗦𝘂𝗺𝗺𝗮𝗿𝘆  • 𝗦𝗽𝗿𝗶𝗻𝗴 𝗕𝗼𝗼𝘁 𝟮.𝟳 + 𝗝𝗮𝘃𝗮 𝟭𝟳: Works but limited in taking advantage of Java 17’s newer capabilities.  • 𝗦𝗽𝗿𝗶𝗻𝗴 𝗕𝗼𝗼𝘁 𝟯.𝘅 + 𝗝𝗮𝘃𝗮 𝟭𝟳/𝟮𝟭: Fully optimized, future-ready, and ideal for cloud-native architectures. 𝗔𝗿𝗰𝗵𝗶𝘁𝗲𝗰𝘁𝘂𝗿𝗮𝗹 𝗖𝗼𝗻𝘀𝗶𝗱𝗲𝗿𝗮𝘁𝗶𝗼𝗻𝘀  • Move to 𝗝𝗮𝘃𝗮 𝟭𝟳 𝗼𝗿 𝗹𝗮𝘁𝗲𝗿 to take advantage of enhanced JVM features and LTS stability.  • Use 𝗦𝗽𝗿𝗶𝗻𝗴 𝗕𝗼𝗼𝘁 𝟯.𝘅 to leverage the 𝗝𝗮𝗸𝗮𝗿𝘁𝗮 𝗘𝗘 𝟵+ ecosystem and modern frameworks.  • Explore 𝗩𝗶𝗿𝘁𝘂𝗮𝗹 𝗧𝗵𝗿𝗲𝗮𝗱𝘀 (𝗝𝗮𝘃𝗮 𝟮𝟭) if your application handles a high volume of concurrent requests. In summary, the combination of 𝗝𝗮𝘃𝗮 𝟭𝟳+ 𝘄𝗶𝘁𝗵 𝗦𝗽𝗿𝗶𝗻𝗴 𝗕𝗼𝗼𝘁 𝟯.𝘅 provides the most balanced approach for building scalable, maintainable, and future-ready enterprise applications. 𝗪𝗵𝗮𝘁 𝘃𝗲𝗿𝘀𝗶𝗼𝗻 𝗰𝗼𝗺𝗯𝗶𝗻𝗮𝘁𝗶𝗼𝗻 𝗮𝗿𝗲 𝘆𝗼𝘂 𝗰𝘂𝗿𝗿𝗲𝗻𝘁𝗹𝘆 𝘂𝘀𝗶𝗻𝗴 𝗶𝗻 𝘆𝗼𝘂𝗿 𝗽𝗿𝗼𝗱𝘂𝗰𝘁𝗶𝗼𝗻 𝗲𝗻𝘃𝗶𝗿𝗼𝗻𝗺𝗲𝗻𝘁? I’m curious to hear how teams are managing their upgrade paths. #React #Angular #Frontend #WebDevelopment #JavaScript #Java #SpringBoot #Nodejs #APIDesign #Microservices #BackendDevelopment