The article presents Zheng, a full‑stack J2EE enterprise solution that integrates Spring, MyBatis, Dubbo, and a rich set of micro‑service modules, detailing its architecture, technology stack, environment setup, deployment procedures, and coding conventions for building scalable backend systems.
A Spring‑based service repeatedly hung because Redis connections were never returned to the pool, leading to thread starvation; the article walks through the investigation using top, jstack, Arthas, and code analysis, then shows the proper way to use RedisCallback and release connections to prevent the deadlock.
This article introduces Aspect‑Oriented Programming in Java, explaining how AOP separates cross‑cutting concerns like logging using join points, pointcuts, advice, and aspects, and demonstrates dynamic proxies, various advice types, XML configuration, and aspect ordering within Spring AOP.
After a week of intermittent API hangs in an internal sandbox, we traced the issue to Redis connection pool blocking caused by missing max‑wait configuration, leading to threads waiting indefinitely; by adjusting Jedis pool settings, using proper connection release, and avoiding unsupported commands, the deadlock was resolved.
Learn how to implement a robust request logging aspect in Spring using AOP annotations, covering pointcut definition, before/around/after advice, handling high concurrency, serializing logs, capturing errors, and adding traceId support for better traceability in backend services.
The article analyzes a Spring Boot transaction issue where a @Transactional method called from another non‑transactional method fails to roll back, explains the underlying propagation and proxy mechanisms, and presents two practical solutions—including using the bean’s proxy via AopContext with exposeProxy enabled—to ensure proper rollback.
This article compares the usage, performance, and internal implementation of popular Java bean‑mapping tools—Spring BeanUtils, Apache BeanUtils, CGLIB BeanCopier, Dozer, and Orika—providing benchmark results, code examples, and detailed analysis to help developers choose the most efficient solution for their layered architectures.
This article explains Alibaba’s Java guidelines for using @Transactional, categorizes checked and unchecked exceptions, shows how Spring’s default rollback behavior works, and provides practical examples of configuring rollback rules, avoiding common pitfalls, and best practices for applying @Transactional in backend Java applications.
This article explains the differences between Spring's @Autowired, @Resource, and @Inject annotations, the recommended injection methods, how the IDE warns against field injection, and best practices for constructor, setter, and field injection to write clean, maintainable Java code.
This tutorial explains the concept of Inversion of Control in Spring, demonstrates how to configure beans with XML, compares BeanFactory and ApplicationContext, explores bean scopes and lifecycle, and provides detailed examples of constructor, static‑factory, instance‑factory, and collection injection techniques.
This tutorial demonstrates how to create JavaBeans, DAO interfaces, and implementations, use JDK dynamic proxies to expose proxy classes, troubleshoot method‑level proxy failures, and apply Spring AOP with ProxyFactory or @Aspect, while also covering transaction pitfalls and best‑practice configurations.
This article explains how to design and implement a user‑customizable scheduled‑task component in Java, addressing the limitations of open‑source frameworks by separating task creation, loading, scheduling, and execution, and provides practical code examples for robust backend task management.
This article explains the purpose and inner workings of Spring’s @Transactional annotation, detailing how AOP creates proxies, defines pointcuts, and orchestrates transaction management through BeanPostProcessors, advisors, interceptors, and the TransactionInterceptor, illustrated with source code snippets and diagrams.
This article explains the JSR‑250 @PostConstruct annotation, its specifications, how Spring implements its lifecycle handling, execution timing, practical code examples, the deprecation in Java 9+, and alternative approaches such as InitializingBean and DisposableBean.
This article explains the purpose of Spring's @Transactional annotation, how it leverages AOP and dynamic proxies to manage transactions, and walks through the core source‑code components—including BeanPostProcessor, advisors, TransactionInterceptor, and the transaction lifecycle—illustrated with concrete code examples.
This article examines whether Service and DAO layers in Java backend projects require interfaces, arguing that with dependency‑injection frameworks like Spring the interfaces are often unnecessary, while outlining development workflows, project structures, and scenarios where interfaces remain useful.
This article explains the difference between shallow and deep copying in Java, compares Apache BeanUtils and Spring BeanUtils with code examples, highlights performance and safety concerns, and recommends using Spring BeanUtils or alternative libraries for efficient property transfer between objects.
This article explains three methods to inject a specific service implementation into a Spring controller—using @Autowired with @Qualifier, using @Resource with type, and using named @Service beans combined with @Resource(name), including code examples and differences between @Autowired and @Resource.
This article explains Spring's Lifecycle and SmartLifecycle interfaces, shows how to implement custom beans that react to container start and stop events, provides complete code examples, and demonstrates the automatic startup and ordered shutdown behavior of SmartLifecycle in a Spring Boot application.
This article explains the Template Method design pattern, illustrating its algorithm skeleton and step customization with Java code examples, and demonstrates real‑world applications in Spring, MyBatis, and other backend frameworks, highlighting advantages, drawbacks, and practical implementation details.
This article walks through ten practical scheduling solutions—from Linux crontab and JDK utilities to Spring Task, Spring Quartz, and distributed frameworks like XXL‑Job and Elastic‑Job—explaining their usage, configuration, code examples, and pros and cons so developers can pick the right tool for any business need.
This article explains MyBatis streaming queries using the Cursor interface, demonstrates how to define a Mapper that returns a Cursor, shows common pitfalls with closed connections, and provides three solutions—manual SqlSession handling, TransactionTemplate, and @Transactional—to keep the database connection open while iterating results.
This article explains Spring's core concepts such as IOC, DI, and AOP, demonstrates building a simple Hello World with SpringBoot, then shows how to recreate the same functionality using raw Servlets and a handcrafted mini‑Spring framework with full code examples.
This article explains typical situations where Spring @Transactional annotations fail—such as non‑public methods, beans not managed by the container, internal method calls, non‑RuntimeException throws, caught exceptions without rethrow, incorrect propagation settings, and unsupported MyISAM storage—and provides concrete code examples and fixes to ensure proper transaction behavior.
This article explains the Same Origin Policy, introduces the CORS standard, details required response headers, and provides three practical Spring implementations—global config, filter, and annotation—to enable cross‑origin requests efficiently.
This article provides a comprehensive overview of the Spring framework, covering its core modules, version compatibility, core concepts such as IoC and AOP, proxy implementations, bean factories, lifecycle management, transaction handling, MVC architecture, Spring Boot, Spring Cloud, and common annotations for Java backend development.
This article explains why browsers enforce same‑origin restrictions, defines cross‑origin requests, lists the limitations of non‑same‑origin interactions, and presents five practical Java backend solutions—including a global CorsFilter bean, WebMvcConfigurer override, @CrossOrigin annotation, manual response headers, and a custom filter—complete with code examples.
This article explains the Service Provider Interface (SPI) concept, demonstrates how Java's built‑in SPI, Dubbo's enhanced SPI, and Spring's SPI work with code examples, compares their strengths and limitations, and discusses classpath ordering and extension loading issues.
This article explains the Template Method design pattern, illustrating its structure with Java drink‑making examples, discussing hook methods, and showing real‑world usages in JDK’s Comparable and Spring’s ApplicationContext, while highlighting advantages, drawbacks, and practical scenarios.
This article explains how to achieve database read‑write separation in a Spring application by using AbstractRoutingDataSource for routing, ThreadLocal for context, AOP interceptors for automatic switching, and provides a complete example with configuration, service code, and test cases.
This article describes how a Java backend service suffering from high CPU load and unstable Hystrix circuit breaking was diagnosed and optimized—using jtop for JVM profiling, refactoring JSON/Bean handling, switching Hystrix isolation modes, improving logging, and tweaking circuit‑breaker settings—to double its QPS capacity and achieve rapid recovery after traffic spikes.
This article explains why browsers enforce the same‑origin policy, defines cross‑origin requests, outlines the restrictions of non‑same‑origin interactions, and presents five practical methods—including a global CorsFilter, WebMvcConfigurer, @CrossOrigin annotation, manual header setting, and a custom filter—to implement CORS in Java Spring backends.
The article recounts a production incident caused by an ungraceful RocketMQ consumer shutdown, analyzes the root cause involving Spring's bean destruction order and ShutdownHook behavior, and presents two solutions—using the official Spring‑Boot starter with SmartLifecycle or handling ContextClosedEvent—to achieve orderly termination.
In a late-night deployment, the author traced a persistent ‘DataSource already closed’ error to an ungraceful RocketMQ consumer shutdown, explored Spring’s ShutdownHook behavior, and ultimately implemented a SmartLifecycle-based solution for orderly bean destruction.
This article explains typical reasons why @Transactional may not work in Spring applications—such as non‑public methods, beans not managed by the container, internal method calls, non‑RuntimeException throws, swallowed exceptions, wrong propagation settings, and unsupported MySQL storage engines—and provides concrete code examples and fixes for each case.
This article explains why PageHelper pagination yields incorrect totals when list operations are performed before or after pagination, analyzes the underlying cause that startPage only affects subsequent SQL, and provides a step‑by‑step solution that processes the list after pagination and returns a correctly populated PageInfo object.
This article explains why local in‑memory locks fail in distributed environments, introduces the concept of distributed locks, and walks through five progressive Redis‑based lock implementations—bronze, silver, gold, platinum, and diamond—detailing their principles, code examples, advantages, and shortcomings.
This article explains the two‑phase lifecycle of Spring beans, covering container startup tasks, metadata loading, bean definition registration, and the detailed instantiation process including object creation strategies, BeanWrapper, property injection, Aware interfaces, post‑processors, and custom init/destroy logic.
This article explains how the Spring IoC container prepares and creates Bean instances, detailing the two main phases—container startup and Bean instantiation—along with the roles of BeanDefinition, BeanFactoryPostProcessor, BeanWrapper, Aware interfaces, BeanPostProcessor, and custom initialization and destruction logic.
The 2020 State of Spring report reveals that the majority of Java developers favor Spring/Spring Boot, spending more time on unit testing, achieving higher code quality, and appreciating benefits such as easier web/API setup and robust testing support, with user adoption rising from 60% to 86%.
This article explains three typical situations where Spring's @Transactional annotation fails—non‑public methods, internal method calls, and caught exceptions—detailing the proxy‑based AOP mechanism, source code examples, and how to diagnose and resolve each issue.
This article explains how to achieve graceful shutdown for Dubbo services by leveraging operating‑system signals, Docker commands, JVM shutdown hooks, Spring event mechanisms, and Dubbo's own extensions, illustrating each layer with code examples and best‑practice recommendations.
This article explains three typical situations in which Spring's @Transactional annotation becomes ineffective—non‑public methods, internal self‑calls, and caught exceptions—illustrates each case with runnable code examples, and dives into the underlying AOP and transaction‑management source code to show why the proxy logic is bypassed.
EasyJDBC is a Java library built on Spring's JdbcTemplate that adds JPA‑style annotations, dynamic entity mapping, chainable query APIs, and broad database support, with Maven coordinates for both core and Spring Boot starter packages and a detailed changelog for version 2.1.0.
This article explains the core concepts of Spring's Inversion of Control (IoC) and Dependency Injection (DI), illustrating how a container takes over object creation and wiring, why this reversal improves modularity and testability, and how the two ideas are essentially two views of the same design principle.
The article analyzes three typical situations—non‑public methods, internal self‑calls, and caught exceptions—that cause Spring's @Transactional annotation to be ineffective, explains the underlying proxy and AOP mechanisms, and provides Java code samples and test cases to illustrate each case.
This guide explains how to replace the legacy Alipay transfer API with the new alipay.fund.trans.uni.transfer interface by upgrading the SDK, configuring certificates, adding Maven dependencies, and implementing Spring components and utility classes for secure backend payment processing.
Explore ten practical Java scheduling options—from Linux crontab and JDK Thread/Timer to Spring Task, Quartz, and distributed frameworks like XXL‑Job, Elastic‑Job, Saturn and TBSchedule—detailing setup, code examples, advantages, drawbacks, and best‑fit scenarios for reliable task automation.
An in‑depth guide to the Spring framework covering its lightweight architecture, core principles such as IoC, DI, and AOP, key design patterns, module structure, bean lifecycle, circular dependency handling, and essential annotations for building robust Java backend applications.
This article provides a comprehensive overview of the Spring framework, covering its lightweight architecture, core principles such as Inversion of Control and Dependency Injection, AOP mechanisms, design goals, module structure, common design patterns, bean lifecycle, circular dependency handling, and the most frequently used Spring annotations with code examples.
This article outlines common situations that cause Spring @Transactional to fail—such as non‑public methods, internal method calls, unmanaged beans, non‑runtime exceptions, silent catches, incorrect propagation settings, and unsupported MySQL storage engines—and provides practical solutions to ensure transaction reliability.
This article explains Spring's warning about field injection, compares constructor, setter, and field injection methods, outlines the drawbacks of field injection, and recommends using constructor or setter injection for safer, more maintainable Java applications.
This article explains the main reasons why Spring's @Transactional annotation may become ineffective—including non‑public method modifiers, internal method calls, and swallowed exceptions—provides code examples, test cases, and a deep dive into the underlying proxy and AOP mechanisms.
The article demonstrates how to create a custom @ValidShop annotation and an AOP aspect that intercepts Spring MVC controller methods, extracts the annotated parameter via reflection, validates the shop code through a helper service, and proceeds only when the check succeeds.
This article introduces Alibaba Sentinel, an open‑source flow‑control framework for distributed services, covering Maven integration, dashboard setup, configuration of flow, degrade and hotspot rules, the @SentinelResource annotation, XCloud Sentinel starter usage, and a deep dive into its slot‑chain architecture and sliding‑window algorithm.
The article explains that MyBatis returns the constant -2147482646 when the executor type is set to BATCH, shows how to trace the source code to uncover this behavior, and provides a simple configuration change to restore correct update counts.
This article examines the challenges of building a generic TCC distributed‑transaction framework on Spring, explaining why every TCC service must participate in RM‑local transactions, why the framework should intercept the Spring TransactionManager, how to handle fault recovery, idempotency of Confirm/Cancel, and the pitfalls of relying on Cancel for rollback, concluding with practical recommendations.
This article provides a curated collection of over 250 interview question links covering Java fundamentals, Spring framework, databases, Redis, messaging, concurrency, and system design, organized by issue numbers to help developers prepare for technical interviews.
This article explains the core principles of Spring transaction management, covering basic JDBC transaction steps, declarative @Transactional usage, AOP proxy mechanisms (JDK dynamic proxy and CGLIB), transaction propagation attributes, isolation levels, nested transactions, and Spring Boot support, with practical code examples.
This article compiles 30 essential Java interview questions covering OOP fundamentals, collections, concurrency, JVM internals, Spring framework, and performance optimization, providing concise explanations and key concepts to help backend developers prepare effectively for technical interviews.
This article outlines five Spring-based approaches for using Apache RocketMQ—including Spring Messaging, Spring Cloud Stream, Spring Cloud Bus, Spring Cloud Data Flow, and Spring Cloud Function—detailing each project's features, typical use cases, and how they fit into modern Java microservice architectures.
This article walks through Spring’s container initialization, detailing the refresh method, XML parsing, BeanDefinition creation and registration, and the role of post‑processors, providing a clear roadmap for readers to understand and remember the core IoC workflow.
This comprehensive guide walks Java developers through setting up PowerMock and Mockito, demonstrates creating and spying on mocks, stubbing methods, using parameter matchers, verifying interactions—including static and private members—and explains essential annotations and best‑practice principles for robust, maintainable unit tests.
This article explains the five Spring AOP advice types, their execution order when combined in a single aspect, and provides a complete Java code example demonstrating before, after, after‑returning, after‑throwing, and around advices with normal and exceptional flows.
This article provides a comprehensive overview of Spring Expression Language (SpEL), detailing its supported expression types, case‑insensitive keywords, step‑by‑step usage flow, core interfaces, and concrete code examples for literals, arithmetic, relational, logical, ternary, Elvis, variable handling, and property navigation.
This article explains how to simplify complex Java code by using PowerMock and Mockito for unit testing, covering environment setup, mock, spy, when, parameter matchers, verification, static method mocking, private field and method handling, and essential annotations with practical code examples.
This article explains how Aspect‑Oriented Programming (AOP) can replace repetitive try‑catch blocks in Dubbo services, introduces core AOP concepts such as JoinPoint, Pointcut, and Advice, and compares static, JDK dynamic, and CGLIB dynamic proxy implementations with practical Java code examples.
The Spring nohttp project is an open‑source tool that scans and replaces insecure http:// URLs with HTTPS, preventing man‑in‑the‑middle attacks, updating Maven and documentation links, offering multiple modules and a command‑line interface, and providing example XML configuration for secure classpath resolution.
Integrating a React front‑end with a Java back‑end required fixing HTTPS‑to‑HTTP CORS errors by serving the React index.html from the backend, switching @RestController to @Controller for sub‑path routing, adding Thymeleaf, using a Chrome redirect plugin and crossorigin tags, and disabling lazy‑loaded asset URLs during local development, highlighting that true front‑end/back‑end separation remains elusive.
This article introduces seven open‑source OAuth/SSO solutions—including oauth2‑shiro, tkey, MaxKey, spring‑lhbauth, oauth2, oauthserver, and JustAuth—detailing their features, supported protocols, and repository links to help developers implement secure authentication and token management in web and mobile applications.
This article explains Spring's approach to resolving circular dependencies in singleton beans using a three‑level cache, contrasts it with prototype bean limitations, provides a simplified implementation example, and draws an analogy to the classic two‑sum algorithm to illustrate the core concept.
This guide walks you through setting up Spring Authorization Server 0.1.0 on Spring Boot 2.4.2, covering Maven dependencies, bean configurations, token customization, and testing with curl commands for authorization code flow, token issuance, refresh, and revocation.
The article explains the core concept of Inversion of Control (IoC), how a third‑party container manages resources to reduce coupling, illustrates the idea with everyday examples, and clarifies the related terms dependency injection and control inversion, especially in the context of Spring.
This article explains how Spring 5.0 reads configuration and annotations, manages bean lifecycles, utilizes BeanPostProcessor extensions, addresses key issues such as FactoryBean vs BeanFactory and circular dependencies, and provides sample code to demonstrate these concepts.
The article explains Spring's warning about field injection, compares constructor, setter, and field injection methods with code examples, outlines the drawbacks of field injection such as final‑field incompatibility, hidden dependencies, and tight IOC coupling, and recommends using constructor injection for required beans and setter injection for optional ones.
This article provides a comprehensive overview of the design patterns used in the Spring framework—including Simple Factory, Factory Method, Singleton, Adapter, Decorator, Proxy, Observer, Strategy, and Template Method—explaining their implementation, underlying principles, and practical significance with code examples.
This article provides a comprehensive overview of how Spring implements classic design patterns such as Simple Factory, Factory Method, Singleton, Adapter, Decorator, Proxy, Observer, and Template Method, explaining their implementation details, underlying principles, and practical code examples within the Spring container.
This article explains how Spring resolves circular dependencies in singleton beans using a three‑level cache, contrasts it with prototype beans, provides a minimal reflective implementation, and draws an analogy to the classic two‑sum algorithm to illustrate the core principle.
This article explains various ways to execute custom logic during Spring container startup, covering bean constructors, @PostConstruct, InitializingBean, ApplicationListener events, @EventListener, constructor injection, CommandLineRunner, and SmartLifecycle, with code examples and usage guidelines.
The 2021 Online Scala Meetup organized by Tubi featured four technical talks covering a fully reactive ad‑serving platform built with Scala and Akka‑Streams, a pragmatic take on functional programming, Scala 3 typeclass implementation, and a Spring‑Akka microservice integration, followed by summaries and recruitment information.
This article explores nine key Spring framework design patterns—including Simple Factory, Factory Method, Singleton, Adapter, Decorator, Proxy, Observer, Strategy, and Template Method—detailing their implementation, underlying principles, and practical code examples, while highlighting how they enable loose coupling and extensibility in backend development.
This article explains how to design a unified JSON response structure for backend APIs, define systematic status codes and messages, and implement a global @ResponseResult annotation with interceptors and ResponseBodyAdvice to automatically wrap controller results in a clean, maintainable way.
This article walks through the fundamentals of Spring AOP, showing how to replace repetitive logging code with AspectJ‑driven aspects, explains core AOP concepts, pointcut expressions, proxy creation mechanisms, advice types, caching behavior, and common pitfalls for Java backend developers.
This article explains how the Spring framework embodies nine classic design patterns—including Simple Factory, Factory Method, Singleton, Adapter, Decorator, Proxy, Strategy, Observer, and Template Method—detailing their implementation principles, core code snippets, and the benefits they bring to dependency injection and bean lifecycle management.
Caffeine is a high‑performance Java 8 local‑cache library that replaces Guava by using the W‑TinyLFU algorithm with three‑queue LRU structures and lock‑free read/write buffers, offering extensive configuration, dynamic runtime adjustments, and safe back‑source loading with distributed locks to prevent cache‑stampede.
This article explains what a streaming query is, introduces MyBatis's Cursor interface and its methods, demonstrates common pitfalls such as the cursor being closed prematurely, and provides three practical solutions using SqlSessionFactory, TransactionTemplate, and @Transactional to keep the database connection alive during streaming reads.
This article explains how to protect front‑back separated APIs using a request signature scheme, detailing the required parameters, signature generation algorithm, Java filter implementation, anti‑leech timing checks, nonce usage, and duplicate‑submission prevention with Redis.
This article provides an in‑depth tutorial on Spring Validation, covering basic usage, dependency configuration, requestBody and requestParam validation, unified exception handling, group and nested validation, collection checks, custom constraints, programmatic validation, fail‑fast mode, and the differences between @Valid and @Validated.
This article explains how to configure Spring's thread pool, when thread‑context copying is needed, and how to implement a TaskDecorator to propagate execution context such as authentication or tracing information across asynchronous tasks.
This article explains the concepts of shallow and deep copying in Java, demonstrates how to use Apache BeanUtils and Spring BeanUtils for property copying between objects, compares their implementations and performance, and recommends alternative tools for efficient object mapping.
This article explains how to design a unified API response format in a Spring backend by defining a JSON result structure, using standardized status codes, creating a @ResponseResult annotation, and implementing interceptors and ResponseBodyAdvice to automatically wrap controller outputs for cleaner, more maintainable code.
This article explains how Spring transaction management works, details its declarative and programmatic integration methods, examines core implementation classes and AOP proxies, and highlights frequent pitfalls such as ineffective transactions, rollback failures, and timeout issues, providing code examples and solutions for Java backend developers.
This article presents a detailed Java learning roadmap covering fundamentals, core language features, the Spring framework, microservices, databases, DevOps tools, project experiences, and soft skills, guiding beginners to become proficient backend developers.
This article introduces mock testing for Spring MVC controllers, explains why mocks are useful, describes the main MockMvc components, shows required Maven dependencies, and provides complete example test cases for both view‑returning and JSON‑returning endpoints using JUnit and MockMvc.
This article explains the concept of streaming queries in MyBatis, describes the Cursor interface and its methods, demonstrates common pitfalls that cause cursor closure errors, and provides three practical solutions—using SqlSessionFactory, TransactionTemplate, or @Transactional—to keep the database connection open during iteration.
This article introduces the most commonly used Spring framework annotations—including core, MVC/REST, Boot, stereotype, data access, scheduling, and testing annotations—explains their purposes, usage scenarios, and provides Java code examples illustrating how to apply them in typical Spring applications.
A seasoned backend tech manager shares his journey from .NET to Java, exposing common interview traps—from misleading resumes and weak fundamentals to fierce market competition—and offers practical advice to help developers navigate career transitions successfully.
This article explains how to design a consistent JSON response structure for Spring-based micro‑service APIs, introduces a Result wrapper class, demonstrates annotation‑driven response handling, and shows controller, interceptor, and advice implementations to produce clean, maintainable backend responses.
This article examines whether Service and DAO layers in Java Spring projects should always have interfaces, discusses the arguments for and against using interfaces, and proposes practical structuring and dependency‑injection techniques to decide when interfaces are truly necessary.
This article provides a detailed tutorial on integrating Kafka with Spring using Spring‑Kafka, covering simple setup, embedded Kafka testing, topic creation, message sending and receiving, transaction support, listener configurations, manual acknowledgment, error handling, retry and dead‑letter queues, and related code examples.
