This article examines common misuse of base Controller and Service classes in Java Spring projects, explains why they violate the Liskov Substitution Principle, and provides practical steps to split, refactor, and properly structure code across the three‑tier architecture.
This article provides a comprehensive guide to essential Spring annotations—including @Controller, @RestController, @Service, @Autowired, @RequestMapping, @ModelAttribute, @Cacheable, @CacheEvict, @Resource, @PostConstruct, @PreDestroy, @Repository, @Component, @Scope, @SessionAttributes, @Required and @Qualifier—explaining their purposes, usage patterns, and practical examples with accompanying diagrams.
This article introduces QMQ, Qunar's internal distributed message queue, covering its background, design motivations, core concepts, code examples for producing and consuming both real‑time and delayed messages, transactional messaging support, and the overall architecture of its metaserver, broker, and delay components.
This article presents a curated list of the most popular Java open‑source projects on GitHub for July, highlighting eleven repositories—most of them Spring‑based—along with their star counts, brief descriptions, and links for developers seeking valuable resources.
This article examines common misuse of base Controller and Service classes in Java micro‑service projects, critiques embedding business logic in Controllers, exposing persistence models to APIs, and offers concrete refactoring steps, project structuring patterns, and best‑practice guidelines to restore a clean three‑layer architecture.
This article outlines ten frequent errors that Java backend developers make—from over‑focusing on low‑level details and leaking internal structures to neglecting separation of concerns, proper exception handling, multithreading, validation, XML configuration, profile management, dependency injection, and testing—offering practical guidance to prevent each pitfall.
This article explains how to diagnose and manually re‑execute a Spring @Scheduled task that fails to send notifications by using Arthas to obtain the ApplicationContext, invoke the bean method, and reveals that a missing timeout in Hutool caused the original hang.
This article compares Spring's traditional RestTemplate blocking client with the newer reactive WebClient non‑blocking client, explaining their underlying mechanisms, performance differences under concurrency, and provides complete code examples for both approaches, helping developers choose the appropriate tool for efficient HTTP calls.
This article compiles a comprehensive set of Ant Financial interview questions covering Java fundamentals, concurrency, Spring, Linux, database design, NoSQL, distributed systems, and personal experience topics across the first, second, and third interview rounds.
This article provides a comprehensive overview of core Java concepts and related technologies, covering Spring's lifecycle, TCP three-way handshake and four-way termination, thread pool execution flow, JVM memory structure and Java Memory Model, as well as Spring MVC, JDBC, Spring Cloud components, and Dubbo service framework.
This comprehensive guide explores the fundamentals of the Spring framework—including its core modules, dependency injection, IoC, bean scopes, configuration styles, annotation-driven setup, event handling, and common design patterns—providing Java developers with practical examples and code snippets to master Spring's capabilities.
This article provides a comprehensive overview of the Spring framework, Spring MVC, and Spring Boot, explaining how dependency injection reduces boilerplate and enables loose coupling, illustrating code examples with and without DI, and describing Spring Boot’s auto‑configuration, starter projects and typical starter options for building modern Java backend applications.
This article completes the Spring Bean lifecycle overview by illuminating the remaining phases, explains how various XxxxAware interfaces are invoked during bean initialization, demonstrates common pitfalls with constructor injection, and provides code examples for implementing and using Aware interfaces such as BeanNameAware and BeanFactoryAware.
This article explains the dangers of XSS and SQL injection attacks, demonstrates realistic attack scenarios, and provides a comprehensive backend solution using Spring AOP, HttpMessageConverter, custom Servlet Filters, request wrappers, and ESAPI to sanitize inputs and protect web applications.
This article explains a Java backend architecture with front‑end/back‑end separation, deployment diagrams, the concepts of thread, process and distributed locks, implementations using database optimistic locking, Redis and Zookeeper, session handling in distributed systems, and various related code examples and best‑practice notes.
This article explains the code types involved in synchronous remote calls, demonstrates how blocking IO leads to callback hell, and shows how to simplify the programming model using Java CompletableFuture, AsyncHttpClient, and Project Reactor’s reactive streams to efficiently retrieve city data.
This article explains how Spring registers bean definitions through various mechanisms such as BeanDefinitionRegistryPostProcessor, BeanFactoryPostProcessor, annotations, XML, @Import, ImportSelector and ImportBeanDefinitionRegistrar, using analogies and code examples to illustrate the process.
This article explains the fundamental role of Spring's BeanDefinition as the core data structure that records all bean metadata, compares it to real‑world analogies, lists the key BeanDefinition interface methods, demonstrates registration via annotations and @Bean methods, and shows how to inspect bean definitions at runtime.
This tutorial explains how to use Spring's RestTemplate to download large files without exhausting memory, covering pitfalls of default methods, implementing a custom ResponseExtractor to stream data to disk, and adding support for resumable downloads via Range headers.
This article compares Spring's BeanFactory and ApplicationContext, explaining their roles in retrieving beans, detailing lazy versus eager loading, providing Java and XML code examples, and offering guidance on when to choose each interface for efficient backend development.
This tutorial explains the fundamentals of Aspect Oriented Programming (AOP) and demonstrates how to create a logging aspect in a Spring MVC application, covering AOP terminology, Spring annotations, pointcut expressions, a WebLog DTO, the WebLogAspect implementation, and how to test the logging output via Swagger UI.
This article presents a curated list of the most popular Java open‑source projects on GitHub for May, highlighting each repository's purpose, star count, and key features ranging from algorithm visualizations and interview prep notes to full‑stack e‑commerce platforms and core Spring frameworks.
This article provides an in‑depth, English‑language overview of the Spring framework, covering its purpose, core modules, IoC and AOP principles, bean scopes and lifecycle, transaction management, MVC architecture, and the design patterns it employs, all without heavy code examples.
This article reviews the most frequently applied design patterns in Spring—including IoC/DI, Factory, Singleton, Proxy (AOP), Template Method, Observer, Adapter, and Decorator—explaining their purpose, how Spring implements them, and providing concise code examples for each.
This article explains how to apply the Strategy pattern within a Spring project, covering background, learning objectives, step‑by‑step code examples for query services A, B, and C, the three‑part invocation process, and both list‑based and map‑based configurations.
This article explains Youzan’s layered unit‑testing framework for microservice applications, outlines typical pain points such as massive test‑case rewrites, unstable test data, and missing result verification, and demonstrates how tools like DbUnit, H2, springockito, spring‑test and PowerMock are combined to provide data preparation, mock injection, automatic cleanup, and declarative result checks.
This article walks through a NullPointerException triggered by Spring Data Redis cache, analyzes the root cause in the RedisCache implementation, reproduces the issue with a Spring Boot demo, and provides practical solutions including connection‑pool tuning and custom cache handling.
This article demonstrates how to replace cumbersome if‑else logic in an order‑processing system with a concise Strategy pattern implementation, using a custom @HandlerType annotation and Spring bean registration to make adding new order types effortless and maintainable.
This article explains how Spring 5’s spring‑core jar incorporates JSR‑305 annotations, introduces the JSR‑305 standard for static analysis, and demonstrates practical usage—including package‑level rules and @Nullable/@NonNull examples—in Spring Boot microservice projects.
This article explains how Spring enables transaction management through @EnableTransactionManagement, details the internal configuration selectors, bean registrations, AOP pointcuts, and the TransactionInterceptor implementation, illustrating the flow of transaction attribute detection, method interception, and exception‑based commit or rollback.
This article chronicles a Chinese computer science graduate’s step‑by‑step evolution from learning basic C and Java in university to building campus apps, winning software contests, mastering Spring, Hadoop, Elasticsearch, and Neo4j, and ultimately landing offers from top tech firms, illustrating the challenges and perseverance required for a successful software engineering career.
This article explains how to implement scheduled tasks in Java, compares built‑in JDK timers, Quartz, and Spring's task scheduler, and provides detailed steps for using Spring XML configuration, annotations, and dynamic code addition together with a guide to writing cron expressions.
This guide lists the core Spring 3 and Spring 4 modules, explains the purpose of each module, and provides the exact JAR dependencies you need to include when using Spring without Spring Boot, helping avoid compilation and runtime errors.
This article explains how to create Java scheduled tasks using Spring's built‑in task scheduler, covering XML configuration, annotation‑based setup, dynamic code addition, and detailed usage of cron expressions for precise timing control.
This article explains how to extract generic type information in Spring, first by manually parsing class hierarchies with reflection and then using Spring 4's ResolvableType utility, providing code examples and API references for fields, methods, constructors, and instances.
This article introduces the EasyRPC framework, explaining its RPC fundamentals, the use of Netty for communication, Spring for configuration, dynamic proxy for transparent calls, Protostuff for message serialization, and details both server-side service publishing and client-side invocation with reconnection handling.
This article introduces the high‑performance Cglib BeanCopier used in the Mica microservice framework, compares its speed with other bean‑copy tools, demonstrates usage with Spring and Lombok, explains the underlying ASM bytecode generation, and discusses current limitations such as lack of chainable beans and primitive‑wrapper handling.
The article explains why using the synchronized keyword together with Spring's @Transactional annotation can lead to lost updates when many threads increment a database field, analyzes the underlying transaction‑proxy interaction, and presents a refactored solution that moves the lock to a separate service to ensure correct results.
This article explains how to simplify Spring service method parameter checks by encapsulating inputs in POJOs, applying bean‑validation annotations, and using a custom AOP aspect or standard @AssertTrue to automatically enforce validation logic.
This article presents a curated collection of over 200 Java interview questions covering fundamentals, collections, concurrency, reflection, web technologies, Spring ecosystem, databases, messaging, and JVM internals, aimed at developers preparing for junior to senior-level interviews and seeking to identify and fill knowledge gaps.
This article explains how Spring implements declarative transaction management using proxies, compares JDK dynamic proxies and CGLIB, demonstrates their behavior with code examples, and clarifies which method modifiers support transactional annotations in Spring applications.
This article discusses practical Java programming techniques, including proper DTO conversion, use of BeanUtils, Lombok annotations, builder patterns, static constructors, validation with JSR‑303, and design considerations such as refactoring, strategy versus state patterns, to help developers write cleaner, more maintainable backend code.
Spring’s shift from XML to annotation‑based configuration is explained, covering @Configuration and @Bean requirements, example Java classes, equivalent XML, annotation definitions, bean scopes, component scanning, unit‑testing, and practical tips for wiring beans without field injection, providing a complete guide for modern Spring development.
This article examines the challenges of using transactions with database read/write splitting, including potential master‑slave switching errors, connection‑pool deadlocks caused by isolation levels and propagation, and presents Spring‑based dynamic data source and transaction management solutions.
This article explores nine commonly used Spring design patterns—including Simple Factory, Factory Method, Singleton, Adapter, Wrapper, Proxy, Observer, Strategy, and Template Method—explaining their concepts, showing XML or Java code examples, and illustrating how Spring implements each pattern in real applications.
This tutorial explains how to integrate the ShedLock library with Spring, covering Maven dependencies, JDBC table setup, required annotations, and example code for creating synchronized scheduled jobs that run on only one instance at a time.
This article explains how Spring implements nine classic design patterns—including Simple Factory, Factory Method, Singleton, Adapter, Decorator, Proxy, Observer, Strategy, and Template Method—through configuration examples and Java code, illustrating their roles in building flexible, maintainable backend applications.
This article explains the essential principles of Spring transaction management, covering transaction propagation, the impact of proxy-based AOP, multithreading safety with ThreadLocal, BeanPostProcessor roles, and common misconceptions illustrated through practical code examples.
This article shares a step‑by‑step experience of redesigning a project’s API by adopting front‑back separation, establishing unified interface conventions, standardizing database IDs, request/response formats, and implementing RESTful methods with Java Spring controllers, while also addressing tooling, documentation, and static resource strategies to dramatically reduce communication overhead and accelerate delivery.
This comprehensive guide walks Java developers through Spring Framework’s essential features—including its modular architecture, dependency injection mechanisms, bean lifecycle, annotation‑based configuration, data‑access support, AOP concepts, and MVC workflow—providing clear explanations, code examples, and visual diagrams to deepen understanding.
This article walks through nine commonly used design patterns in Spring, such as Simple Factory, Factory Method, Singleton, Adapter, Wrapper, Proxy, Observer, Strategy, and Template Method, providing clear explanations, XML configurations, and Java code examples to illustrate each pattern in practice.
This article examines Spring's three annotation-based dependency injection styles—field, constructor, and setter—showing why the widely used field injection is actually the least advisable, and explains the advantages of constructor injection introduced in Spring 4.x with concrete code examples and best‑practice guidelines.
This article chronicles the evolution of the Spring ecosystem—from its origins as a lightweight dependency‑injection framework, through rapid version growth and corporate changes, to the emergence of Spring Boot and Spring IO, highlighting key releases, architectural shifts, and the impact on Java backend development.
This article recounts a candidate's multi‑stage Meituan interview, detailing questions and answers on Java, Spring, multithreading, data structures, JVM, MySQL, design patterns, and system design, providing practical insights for aspiring backend engineers.
This article explains the core concepts of Spring AOP, the proxy design pattern, and provides detailed Java examples of static proxy, JDK dynamic proxy, and CGLIB dynamic proxy, helping readers answer common interview questions and understand how Spring chooses the appropriate proxy implementation.
This article explains Spring Cloud Stream’s default retry mechanism, demonstrates a complete example of producing and consuming messages with intentional failures, shows how to configure retry attempts, and discusses what happens when retries succeed or ultimately fail, providing practical guidance for reliable message processing.
This article explains the purpose of the Service layer in a Java SSM‑based high‑concurrency seckill project, walks through interface design, DTO/VO/PO concepts, provides full Service implementation with transaction management, custom exceptions, enumeration for status codes, Spring XML configuration, and unit testing examples.
This guide walks through downloading and installing Redis, adding Java dependencies, creating a Redis DAO with Protostuff serialization, configuring Spring beans, caching seckill data, implementing a MySQL stored procedure for atomic execution, mapping it with MyBatis, updating service and controller layers, and testing the entire workflow.
This article provides a comprehensive guide to Spring's core annotations—including @Autowired, @Bean, @Qualifier, @Required, @Value, @DependsOn, @Lazy, @Lookup, @Primary, @Scope, @Profile, @Import, @ImportResource, @PropertySource and @PropertySources—explaining their purpose, usage patterns, and code examples for constructor, setter, and field injection in Java applications.
This article explains the purpose and usage of frequently used Spring annotations such as @Controller, @RestController, @Service, @Autowired, @RequestMapping, @RequestParam, @ModelAttribute, @Cacheable, @CacheEvict, @Resource, @PostConstruct, @PreDestroy, @Repository, @Component, @Scope, @SessionAttributes, and @Qualifier, providing code examples and practical notes for Java backend development.
This guide shares actionable strategies for Java backend interview preparation, covering essential Java fundamentals, framework mastery, distributed system concepts, database optimization, Linux troubleshooting, and how to showcase real project experience to stand out from other candidates.
This article provides a detailed, macro‑level walkthrough of Apache Dubbo's startup sequence, covering Spring schema extensions, event‑driven service export, URL construction, local and remote exposure decisions, and the Netty server initialization that together enable transparent Java RPC services.
This article compiles a detailed set of Java backend, concurrency, database, and system design interview topics commonly asked in BAT (Baidu, Alibaba, Tencent) interviews, organized by first, second, and third round questions.
This guide explains why using identical @Input and @Output channel names in Spring Cloud Stream causes bean definition conflicts, and shows how to rename channels and configure them to share the same destination topic so a microservice can safely produce and consume its own messages.
This article details the design of a reusable Java backend framework called lyyzoo, covering coding standards, Maven module hierarchy, dependency management, core utility classes, and Spring configuration for web, JPA, and transaction support, providing a comprehensive guide for building enterprise applications.
This article walks through the complete backend development of a gas purchase‑sale‑stock management system, covering entity and database design, Maven multi‑module project setup, Spring and web.xml configuration, environment‑specific property handling with a portable‑config Maven plugin, and a sample login controller implementation using Java, Spring MVC, and ExtJS.
This article provides a comprehensive, step‑by‑step tutorial on designing and implementing a Java‑based inventory management system, covering requirement analysis, architecture, module design, development environment setup, and deployment using Spring, Spring MVC, Hibernate, ExtJS, Maven, and Tomcat.
This article compiles a comprehensive set of senior Java interview questions used by Meituan, covering concurrency utilities, synchronization, design patterns, JVM memory management, Spring IoC/AOP, database indexing, distributed systems, and more to help candidates prepare effectively.
This article presents a detailed case study of a mid‑size development team’s front‑end and back‑end technology stack, server environment, project workflow, and management practices, aiming to share practical solutions and lessons learned for building and maintaining enterprise‑grade Java applications.
This article explains how to build a high‑performance red‑packet (hong‑bao) service by configuring a RedisTemplate in Spring, writing an atomic Lua script for stock management, persisting results to a MySQL database via JDBC batch processing, and using @Async to off‑load long‑running tasks, complete with code examples and deployment steps.
This article compiles common interview questions and concise answers about Spring, Spring MVC, and MyBatis, covering core concepts such as IoC, AOP, transaction management, controller behavior, annotation usage, design patterns, MyBatis configuration, mapping techniques, pagination, and integration with Ajax.
This article demonstrates how to build a high‑concurrency red‑packet (抢红包) system using Java backend technologies—including MySQL table design, POJOs, MyBatis DAOs, Spring services with transaction management, and a web layer, and discusses performance testing, data consistency issues, and solutions such as pessimistic and optimistic locking.
This article analyzes the challenges of implementing a generic TCC distributed transaction framework using Spring, emphasizing the need for RM‑local transaction integration, transaction manager takeover, fault recovery, idempotency, and proper handling of Try/Confirm/Cancel operations.
This article compiles a comprehensive set of Ant Financial interview questions covering Java fundamentals, data structures, concurrency, JVM internals, Spring framework, Tomcat, Docker, Dubbo, MySQL sharding, and messaging middleware, providing candidates with a detailed study guide for multiple interview rounds.
This article explains how to use Aspect‑Oriented Programming (AOP) in Java backend controllers by defining a unified ResultBean response format, outlining controller coding conventions, and providing complete Java and XML examples for logging, exception handling, and AOP configuration.
This article provides a comprehensive overview of the Quartz Java scheduling framework, detailing its architecture, core components such as Scheduler, Job, Trigger and JobDetail, typical use cases, Spring‑based cluster deployment configurations, monitoring techniques, and the underlying database‑lock synchronization mechanism.
This article provides a systematic summary of Spring's core concepts—including IoC, AOP, bean configuration via XML and annotations, dependency injection mechanisms, transaction management, and web integration—offering Java developers a clear guide to effectively using the framework in real-world projects.
SWAK is a lightweight, Spring-compatible framework that treats product type, category, and region tags as rules, registers multiple implementations during startup, and at runtime selects the appropriate one via priority and reduction, eliminating tangled if-else code, improving reuse, onboarding, and performance for Xianyu’s backend.
This tutorial walks you through the background, learning goals, and detailed Spring-based code examples of the Strategy pattern, including list and map implementations, configuration files, and a complete run‑time demonstration for Java developers.
The article critiques badly written Spring controller and service code, explains how poor coding habits cause maintenance headaches, and demonstrates a cleaner, AOP‑based approach that reduces boilerplate and improves code quality for backend Java applications.
This article provides a detailed overview of the technical interview topics commonly asked by BAT companies and Alibaba, covering data structures, Java advanced concepts, performance optimization, design patterns, Spring, distributed systems, microservices, Docker, and a summary of interview experiences.
This article explains the fundamentals of Spring AOP's JDK and CGLib dynamic proxies, compares their implementation details, presents performance test results across Java 1.6‑1.8, and offers practical guidance on choosing the appropriate proxy based on use‑case.
This article details the design, evolution, and implementation of an online test‑monitoring platform that transforms CI/CD pipelines into proactive alerting systems, covering the initial Spring‑based prototype, its shortcomings, the 2.0 configurable and visual redesign, plugin architecture, and future distributed deployment plans.
A comprehensive collection of over 70 interview questions covering Java concurrency, Spring framework, MySQL optimization, JVM internals, Linux command-line tricks, Redis usage, and system monitoring, designed to help backend engineers prepare for technical interviews across major Alibaba subsidiaries.
This article compiles the most frequently asked Java interview questions—from basic introductions and multithreading concepts to JVM internals, Spring framework details, middleware, database fundamentals, and Redis—providing a comprehensive study guide for job seekers.
The article explains how a microkernel architecture separates a stable core from plug‑in components, enabling static and dynamic composition through annotations or configuration files, illustrated by e‑commerce checkout and iQIYI payment redesign, and introduces the open‑source Navi framework for declarative matcher‑based component selection, highlighting extensibility as essential for rapid business growth.
Explore the GOF 23 design patterns with a deep dive into the Singleton pattern, covering its purpose, characteristics, comparison to static classes, and multiple Java implementations—including eager, lazy, double‑checked locking, volatile, static inner class, and enum approaches—plus Spring’s real‑world usage.
This article walks through nine common design patterns used in the Spring framework—Simple Factory, Factory Method, Singleton, Adapter, Decorator, Proxy, Observer, Strategy, and Template Method—showing their concepts, Spring-specific implementations, and practical code snippets.
This article systematically outlines the essential steps and considerations for creating a classic Java web application, covering environment preparation, Maven scaffolding, logging and database dependencies, DAO design with MyBatis, Spring integration, service-layer best practices, and RESTful controller implementation.
This tutorial provides a step‑by‑step guide for configuring the Alipay sandbox, generating keys, setting up the required database tables, and integrating Alipay payment APIs into a Java SSM project, complete with code snippets, configuration details, and troubleshooting tips.
This article outlines practical techniques for enhancing Java service robustness, covering standardized response structures, thorough parameter validation, retry strategies, idempotent design, and functional programming with lambdas to reduce runtime errors and improve maintainability.
This article explains how a JavaEE project integrates JSP front‑end with Struts2, Spring, and MyBatis on the backend, describes the three‑tier architecture, the role of each layer, database communication with Oracle, and the evolution from classic MVC to Web 2.0 approaches.
This article explains why microservice architectures demand specialized automated testing, compares testing styles such as unit, contract, and end‑to‑end, and walks through a practical Java‑based framework built on Spring, TestNG and Dubbo, including setup steps and code examples.
The article outlines Alibaba’s three‑stage interview assessment—fundamental knowledge, project experience, and project depth—provides key Java and framework topics to study, and explains how mastering these layers can boost both interview performance and everyday development skills.
The article explains how Dubbo's standalone service container loads optional Spring, Jetty, and Log4j modules, details their configuration properties, demonstrates various startup methods, and provides a complete Java implementation of the SpringContainer with start and stop logic, followed by a test main class.
This article outlines the complete set of front‑end, back‑end, database, server, and deployment technologies and best‑practice knowledge a developer needs to build and run a simple yet functional Java Web application, providing a clear big‑picture roadmap for beginners.
This article shares the practical experience, new features, component changes, migration steps, and pitfalls encountered while upgrading an old Spring Boot 1.x backend to Spring Boot 2.0, offering guidance for a smoother transition and highlighting post‑upgrade issues such as path matching, HTTP PUT handling, and Swagger compatibility.
This article explains how to implement scheduled tasks in Spring using the lightweight Spring Task framework, covering both XML‑based and annotation‑based configurations, providing complete code examples, cron expression details, and practical tips for Java backend developers.
This guide outlines a comprehensive, step‑by‑step strategy for preparing Java backend interview candidates—covering architecture, databases, core Java, multithreading, JVM, and practical tips to demonstrate senior‑level expertise.
This article explains the principles of distributed locks, discusses why they are needed in distributed applications, and provides a complete Java implementation using Redis’s NX and EX parameters, including lock acquisition, blocking and non‑blocking modes, unlocking with Lua scripts, configuration, usage examples, and testing strategies.
