This article walks through building complex test‑case search queries using MySQL CASE WHEN, FIND_IN_SET, and MyBatis dynamic SQL, demonstrates converting asynchronous data fetches to synchronous calls with CountDownLatch in Spring, and provides complete Java bean and configuration examples.
This article demonstrates how to use MyBatis to update records with sub‑queries, batch‑insert list‑type attributes, defines the related Java bean, and implements a Spring servlet filter (with request and response wrappers) to log request parameters and response results.
This article analyzes a financial system's duplicate income‑splitting bug caused by concurrent transactions, explains how MySQL isolation levels and Spring transaction propagation contributed to dirty reads, and presents two corrective approaches—adjusting transaction propagation and repositioning Redis locks—to ensure reliable data consistency.
The article explains how to replace repetitive try‑catch blocks with a unified exception handling mechanism in Spring Boot by leveraging @ControllerAdvice, custom BaseException, enum‑driven error codes, Assert utilities, and standardized response objects to improve code readability and maintainability.
This article explains how to replace repetitive try‑catch blocks in Java Spring applications with a unified exception handling mechanism that leverages @ControllerAdvice, custom Assert utilities, and an enum‑based error‑code system to produce clean, maintainable backend code.
This article explains Java's reflection mechanism, covering how to obtain Class objects, the java.lang.reflect API, practical code examples, common use cases such as dynamic proxies, JDBC driver loading, Spring bean initialization, and discusses the advantages and performance drawbacks of using reflection.
This article explains how Spring's bean lifecycle can be customized using BeanPostProcessor, @PostConstruct, InitializingBean, and initMethod, providing code examples, execution logs, and best‑practice scenarios for extending bean creation and initialization in backend Java applications.
This article explains how to replace repetitive try‑catch blocks in Java Spring applications with a unified exception handling strategy that leverages @ControllerAdvice, custom Assert utilities, and enum‑driven error codes to produce cleaner, more maintainable backend code.
This article explains the core principles of Spring transaction management, including JDBC transaction steps, declarative @Transactional usage, AOP proxy mechanisms, propagation behaviors, isolation levels, nested transactions, and Spring Boot support, while also providing code examples and practical guidance for developers.
This page compiles a chronological list of 100 WeChat articles covering Java interview topics, including core language concepts, data structures, concurrency, Spring, MySQL, Redis, and system design, providing readers with direct links to each issue for comprehensive preparation.
This article shows how to replace traditional Spring MVC annotations with Spring 5's functional routing API, covering dependencies, RouterFunction, ServerRequest/ServerResponse, HandlerFunction, RequestPredicate, and demonstrating practical code examples and expected responses.
This article explains how to achieve non‑intrusive, efficient full‑record data change auditing in a Spring‑based backend by leveraging Aspect‑Oriented Programming, custom annotations, and reflection to automatically capture before‑and‑after values for both primary and related tables.
This article explains how to implement the Strategy, Factory Method, and Builder design patterns within a Spring application to decouple reward‑distribution logic, showing interface definitions, concrete implementations, a factory for dynamic bean selection, and a prototype‑scoped builder for request construction.
This article explains why a Spring interface bean can be injected without an explicit bean definition, compares the injection mechanisms of @Autowired and @Resource, and shows how to select a specific implementation when multiple beans implement the same interface.
This article explains the principles and practical implementation of WebSocket, compares it with HTTP, discusses when to use it, and details a complete backend and frontend solution using Spring WebSocket, SockJS, and STOMP for real‑time communication in web applications.
This article explains how to replace repetitive try‑catch blocks in Java backend services with a unified exception handling framework using Spring's @ControllerAdvice, custom @ExceptionHandler methods, enum‑based error codes, and assertion utilities, improving code readability, maintainability, and error response consistency.
This article explains how Spring handles circular dependencies in singleton beans by using a three‑level cache, contrasts it with prototype beans that cannot participate, and demonstrates a minimal implementation that mimics Spring's approach, linking the concept to the classic two‑sum algorithm.
This article explains how Spring resolves circular dependencies for singleton beans using a three‑level cache, demonstrates a simple prototype implementation that mimics Spring's behavior, and relates the problem to the classic two‑sum algorithm to reveal its fundamental nature.
This article explains how to replace noisy try‑catch blocks with Spring's @ControllerAdvice and custom Assert utilities, using enums for error codes, unified response structures, and practical MyBatis‑Plus examples to achieve clean, maintainable backend exception handling.
This article explains how to implement unified exception handling in Spring Boot using @ControllerAdvice and custom Assert utilities, demonstrates reducing repetitive try‑catch blocks with enum‑based error codes, and shows practical testing of various error scenarios including 404, validation, and database failures.
This article explains how Spring resolves circular dependencies in singleton beans using a three‑level cache, why prototype beans cannot participate, provides a minimal example implementation, and draws an analogy to the classic two‑sum algorithm to illustrate the underlying principle.
This article explains the Spring bean lifecycle within an ApplicationContext, detailing container‑level, factory‑level, and bean‑level post‑processors, showing how to implement and register custom processors, and providing code examples and XML configuration to illustrate the execution order and practical usage.
This article explains the warning caused by @Autowired, compares field injection with constructor injection, clarifies Java's initialization order, shows how to fix the issue using constructor injection, and discusses whether adding the final modifier to injected fields is necessary.
This article demonstrates how to replace repetitive try‑catch blocks in Java Spring applications with a unified exception handling approach that leverages @ControllerAdvice, custom Assert utilities, and enum‑based error codes to produce clean, maintainable, and internationalized error responses across controllers and services.
This article examines Spring Boot's auto‑configuration process by analyzing the source code of @SpringBootApplication, @EnableAutoConfiguration, and related classes, explaining how the framework loads configuration classes via SpringFactoriesLoader, processes deferred import selectors, and integrates with the application context during startup.
This article reveals common Java pitfalls—from using Objects.equals versus ==, ternary operator type conversion, generic type mismatches, Set deduplication, BeanUtils property copying, to CGLIB proxy quirks—and provides concrete analysis and practical avoidance techniques for each case.
This article explains what circular dependencies are in Spring, shows three ways the framework handles them—constructor injection, singleton setter injection, and prototype setter injection—illustrates each with Java classes and XML configuration, and clarifies why only the singleton setter approach avoids runtime errors.
Spring has announced a community‑driven Spring Authorization Server project to fill the gap left by the outdated Spring Security OAuth, aiming to provide modern OAuth support within the Spring ecosystem and inviting contributors to help it succeed.
This article explains Spring's five bean scopes, focusing on the differences between singleton and prototype beans, their performance advantages, thread-safety concerns, and why Spring chooses singleton as the default scope.
This article explains the distinctions between Spring and Spring Boot, covering their core concepts, Maven dependencies, MVC and template engine configurations, security setup, bootstrapping mechanisms, packaging options, and deployment strategies, with detailed code examples throughout.
This article explains the benefits of reading source code and provides a step‑by‑step guide for setting up a Gradle‑based environment, downloading, importing, compiling, and debugging Spring Framework source code with practical code examples and IDE configuration tips.
This tutorial walks through creating an empty GitHub repository, importing it, adding a content service and additional microservices, configuring the Maven parent pom, setting up a root Maven configuration and .gitignore, and finally committing the code for the PassJava Java microservice suite.
This article walks through creating a lightweight Spring‑like framework in Java, detailing the project structure, startup process, MVC module initialization, core IOC container design, BeanDefinition handling, bean registration, dependency injection, and circular‑dependency resolution, all illustrated with diagrams and code snippets.
This article explains Spring Boot’s @Transactional implementation, covers transaction isolation levels and propagation, walks through the core source code of TransactionInterceptor and PlatformTransactionManager, and guides you step‑by‑step to create a custom annotation that rolls back on specified exceptions using JDBC and AOP.
This article compares Spring and Spring Boot, explains their core concepts, walks through MVC, template engine, and security configurations, shows Maven and Gradle dependency setups, and details how to package and deploy applications with code examples.
Preparing thoroughly for Java junior and senior technical interviews requires covering core Java concepts, Spring and Spring Boot frameworks, database fundamentals, multithreading, JVM internals, and architectural knowledge, while practicing problem‑solving and understanding interviewers' expectations to increase success chances.
This article explains the purpose of Spring's @Transactional annotation, details its configurable attributes, and enumerates six typical scenarios—such as non‑public methods, wrong propagation settings, self‑invocation, and unsupported database engines—that cause the annotation to become ineffective, providing code examples and solutions.
This article provides a comprehensive guide to Java's reflection mechanism, covering its definition, core capabilities, practical code examples, common API usage, and considerations such as performance and security, enabling developers to understand and apply reflection effectively in real-world projects.
This article explains how to implement token‑bucket rate limiting with Guava's RateLimiter, compare it to leaky‑bucket algorithms, and combine it with optimistic and pessimistic locking techniques to prevent overselling in high‑concurrency flash‑sale applications.
This article explains several typical pitfalls that cause Spring's @Transactional annotation to be ineffective, such as unsupported database engines, unmanaged service beans, internal method calls, non‑public methods, default rollback rules, and missing transaction manager configuration, and provides practical solutions for each case.
This article details a lightweight, low‑intrusion transactional message solution for microservices, covering design principles, database schema, Spring‑based implementation with RabbitMQ integration, compensation mechanisms, scheduling, and testing, illustrating how to achieve reliable asynchronous messaging while maintaining eventual consistency.
This article explains how Spring applies nine classic design patterns—including Simple Factory, Factory Method, Singleton, Adapter, Decorator, Proxy, Observer, Strategy, and Template Method—detailing their implementation approaches, underlying principles, and the benefits they bring to Spring's IoC container and AOP mechanisms.
This article compiles typical Java backend interview questions and detailed answers covering self‑introduction, personal growth, concurrency primitives, JVM memory management, GC tuning, cache design, large‑scale data storage, Spring IoC, AOP, distributed session handling, and common design patterns.
This article explains how Spring's @EnableAsync annotation activates asynchronous method execution, detailing the roles of AsyncConfigurationSelector, ProxyAsyncConfiguration, AbstractAsyncConfiguration, and AsyncAnnotationBeanPostProcessor, and showing the underlying code that creates proxies, advisors, and executors for async processing.
Learn how to enable Spring's @Async support, configure custom executors, use @Async with void and Future return types, and implement custom exception handling for uncaught async errors, providing a complete guide to asynchronous method execution in Spring applications.
This article provides a comprehensive overview of frequently used Spring Boot, Spring MVC, and JPA annotations, explaining their purposes, typical usage patterns, and includes example code snippets to illustrate how they are applied in Java backend development.
This article explains how Spring implements nine core design patterns—including Simple Factory, Factory Method, Singleton, Adapter, Decorator, Proxy, Observer, Strategy, and Template Method—detailing their implementation, underlying principles, and practical significance for Java backend development.
This article explains how the Spring framework implements various classic design patterns—including Simple Factory, Factory Method, Singleton, Adapter, Decorator, Proxy, Observer, Strategy, and Template Method—detailing their implementation mechanisms, underlying principles, and practical significance within Spring's bean lifecycle and extension points.
This article demonstrates how to use Apache POI in a Maven‑based Java project to read and write both XLS and XLSX Excel files, covering library setup, core APIs, data type handling, and practical import/export implementations with Spring MVC and MyBatis.
This article explains the roles of BeanFactory and ApplicationContext in Spring, compares BeanFactory with FactoryBean, and provides detailed code examples showing how to configure and retrieve beans, including custom FactoryBean implementations and the use of '&' to access the FactoryBean itself.
The article introduces the MockRpc platform, which uses Spring‑based extensions and a mock server to fully decouple front‑end services from middle‑end services in a micro‑service architecture, enabling zero‑intrusion testing, configurable mock data, and improved development efficiency for JD Retail.
This article explains how to use Spring's RestTemplate to perform GET, POST, PUT, and DELETE HTTP calls, compares getForObject with getForEntity, demonstrates parameter passing styles, and shows how to handle redirects with postForLocation, providing complete code examples for each operation.
This article explains how to improve the performance of multi‑query server interfaces by converting asynchronous calls to synchronous execution using Spring's @Async annotation and CountDownLatch, outlining suitable scenarios, providing Java pseudocode, and sharing practical implementation tips.
This article explains the Prototype creational design pattern, its definition, key concepts, typical usage scenarios, UML illustrations, and provides a complete Java implementation with code examples, output analysis, and a discussion of its application in Spring's prototype‑scoped beans.
This article reviews Java's history, its widespread industry adoption, and presents a detailed comparison of the nine leading Java web frameworks in 2020, helping developers select the most suitable framework for their specific project needs.
This article explains the complete Spring Bean lifecycle—from bean retrieval, through creation, property population, initialization, and destruction—using detailed flowcharts, step‑by‑step descriptions, and full source code snippets to illustrate each phase.
This article outlines the essential steps for creating a traditional Java web application, covering environment preparation, Maven skeleton creation, required dependencies for logging, databases, persistence, Spring integration, DAO and service layers, unit testing, and RESTful controller configuration.
This article presents a curated list of the ten most essential Eclipse plugins for Java developers, explaining how each tool—ranging from Git integration and Spring support to Maven, SVN, code coverage, and live reload—boosts productivity and streamlines common development workflows.
This article explains the concept of idempotency in web services, analyzes common causes of duplicate submissions, and presents multiple backend solutions—including frontend button disabling, PRG pattern, session flags, local locks using ConcurrentHashMap, AOP interceptors, and distributed Redis locks—accompanied by complete Java code examples.
This tutorial provides a step‑by‑step guide on configuring the Alipay sandbox, generating keys, setting up notification URLs, creating the required database tables, and integrating the full payment flow—including DAO, service, controller, and JSP code—into a Java SSM backend project.
This article compiles over 150 Java interview questions covering collections, JVM tuning, concurrency, Spring framework, design patterns, Spring Boot, Netty, and Redis, providing a comprehensive study guide to help candidates prepare for upcoming interview seasons.
This article provides a systematic tutorial on using Spring‑Kafka, covering basic setup, embedded Kafka for testing, topic creation methods, message sending with KafkaTemplate, transactional messaging, request‑reply patterns, advanced @KafkaListener configurations, manual acknowledgment, listener lifecycle control, SendTo forwarding, and retry with dead‑letter queues, all illustrated with complete code examples.
This article aggregates over forty WeChat posts that cover Java interview topics ranging from Redis and hash structures to Spring lifecycle, multithreading, serialization, and database sharding, providing a valuable reference for developers preparing for technical interviews.
This article surveys Java’s evolution and market dominance, then evaluates the ten leading Java frameworks—Spring, Hibernate, Struts, Play, GWT, Grails, Blade, JSF, and Vaadin—highlighting their key features, use cases, and why choosing the right one is crucial for successful web development.
This article reviews the nine most popular Java frameworks in 2020—Spring, Hibernate, Struts, Play, Google Web Toolkit, Grails, Blade, JavaServer Faces, and Vaadin—detailing their features, industry adoption, and why they remain top choices for building scalable, high‑performance enterprise and web applications.
This article provides a comprehensive introduction to the Spring ecosystem, covering its core concepts such as IoC and AOP, detailing each of the seven framework modules, and explaining related projects like Spring MVC, Spring Security, Spring Data, Spring Boot, and Spring Cloud for modern Java backend development.
This article explains how Spring bean scopes affect thread safety, why most beans are safe when stateless, how to use ThreadLocal correctly, its internal hash‑map design, and the memory‑leak pitfalls that arise when ThreadLocal entries are not cleaned up.
This article lists and briefly describes the ten most starred Java open‑source projects on GitHub for November, covering tools such as NLP libraries, learning guides, big‑data frameworks, rapid‑development platforms, algorithm collections, job schedulers, code‑style checkers, traffic‑control systems, the Spring framework, and service‑discovery solutions.
This article explains the concept of cross-origin, why it occurs in modern web architectures, and provides practical Spring‑based solutions using JSONP and CORS together with jQuery AJAX examples, complete with configuration snippets and code samples.
This article explains how to write integration tests for Spring services that call external APIs by using WireMock to mock HTTP responses, handle dynamic ports, simulate error and timeout scenarios, and adjust exception handling in RestTemplate calls.
This article explains the role of Spring's DispatcherServlet, details its traditional web.xml configuration, walks through its request‑handling workflow, and shows how Spring Boot automatically configures and registers the servlet using concise code examples and annotations.
This article explains how to design a standardized JSON response format, define status codes and messages, and implement a global @ResponseResult annotation with interceptors and ResponseBodyAdvice in Java to simplify controller return values and improve error handling.
This article explains why improper use of ThreadLocal can lead to memory leaks in Java, details the underlying weak‑reference mechanism, and provides practical steps—including explicit removal and Spring integration—to safely manage ThreadLocal data and avoid resource exhaustion.
An in‑depth overview of the Spring ecosystem explains its core container, modules such as AOP, MVC, Data, Security, Boot and Cloud, detailing how IoC and dependency injection simplify Java enterprise development, and guides readers through configuration, architecture, and the advantages of using Spring for modern backend applications.
This article provides a thorough tutorial on using Spring‑Kafka, covering basic Maven setup, producer and consumer code, embedded Kafka for testing, programmatic topic creation, synchronous and asynchronous message sending, transaction handling, request‑reply patterns, advanced @KafkaListener options, manual acknowledgments, lifecycle control, message forwarding with @SendTo, and retry with dead‑letter queues.
This article explains how to build a reusable Java utility for exporting massive Excel reports, covering customizable headers, field formatting, multithreaded data retrieval, asynchronous processing, and provides full source code with detailed analysis and usage instructions.
This article presents a comprehensive, practice‑oriented overview of Domain‑Driven Design, covering its conceptual foundations, project‑level management, architectural layering, design patterns, implementation techniques with Java/Spring, testing, continuous integration, and deployment strategies for enterprise applications.
This article explains how @ConfigurationProperties and @ConfigurationPropertiesScan work in Spring Boot, the differences from @Value, and why upgrading from 2.2.0 to 2.2.1 may cause configuration beans to stop loading.
Recent tech headlines reveal a programmer’s server lockup leading to a startup’s collapse, Microsoft’s entry into the OpenJDK project, Spring Framework 5.1.11 and RxJava 2.2.14 releases, PyCharm 2019.3 EAP adding R support, and Samsung’s decision to dissolve its in‑house CPU team in favor of ARM.
This article compiles detailed notes from three rounds of Meituan’s Java interviews, covering SOA, micro‑services, load balancing, concurrency, JVM internals, Spring, database optimization, and algorithm challenges, while also outlining a learning roadmap for seasoned Java developers.
This article explains how to replace tangled if‑else statements in business code with the Strategy and Factory design patterns, demonstrates their implementation in Java and Spring, and shows how to register strategy beans to improve readability and maintainability.
This article explains why Spring's BeanUtils.copyProperties cannot copy static inner class fields and List properties without proper getters/setters, demonstrates the issue with demo code, and provides practical solutions to ensure successful property copying.
This article explains how excessive if‑else statements in business code hurt readability and maintainability, and demonstrates how to replace them with the Strategy and Factory design patterns integrated with Spring, using a food‑delivery discount example and complete Java code snippets.
This article explains how to replace tangled if‑else logic in business code with the Strategy and Factory design patterns, integrates them into a Spring application, and demonstrates the resulting improvements in readability, maintainability, and extensibility for discount calculations.
In a recent Java backend project, using Spring's BeanUtils.copyProperties to copy a request object with static inner classes and List fields caused missing fields and request failures, revealing the need for proper getters, setters, and separate handling of inner‑class properties.
This article explains how Spring handles circular dependencies through constructor injection errors, demonstrates how setter injection with singleton scope avoids the issue, and shows why prototype‑scoped beans still fail, providing code examples and internal mechanism details.
This article explores Dubbo's graceful shutdown mechanisms across versions 2.5.x, 2.6.x, and 2.7.x, detailing the underlying shutdown hooks, registry and protocol cleanup, Spring integration challenges, and best‑practice configurations to ensure in‑flight requests complete without service disruption.
This article explains the complete Spring Bean lifecycle—including definition via XML, various initialization methods, three ways to obtain and use a bean, and bean destruction techniques—illustrated with Java code snippets and a diagram for clear understanding.
Spring, Spring MVC, Spring Boot, and Spring Cloud are Java frameworks that respectively provide core IoC/AOP functionality, web MVC capabilities, convention‑over‑configuration rapid development, and comprehensive microservice governance, together forming a layered ecosystem for building clean, manageable, and scalable backend applications.
This article outlines ten frequent errors that Java backend developers make—from over‑focusing on low‑level details and leaking internal structures to neglecting proper testing—and offers practical guidelines and examples to write cleaner, more maintainable Spring‑based services.
This article explores the complexities of building a generic TCC distributed transaction framework, emphasizing the need for RM-local transaction integration, Spring TransactionManager takeover, fault‑recovery mechanisms, idempotency guarantees, and proper handling of Try/Confirm/Cancel phases to ensure global consistency.
This article provides a detailed overview of the most commonly used Spring MVC request‑mapping annotations, Spring Bean stereotypes, dependency‑injection and scope annotations, container configuration annotations such as @Autowired and @Primary, and essential Spring Boot annotations, illustrating each with clear code examples and diagrams.
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.
