The article explores how Java has survived massive industry shifts through a vibrant community, extensive open‑source frameworks, continual language evolution, and emerging opportunities like WebAssembly, illustrating why it stays a cornerstone of enterprise and creative software development.
This article explains how to implement a flexible, annotation‑driven data‑masking solution for Java backend services by defining custom masking annotations, serializers, and integrating them into Spring's ObjectMapper to automatically mask sensitive fields in API responses.
This article explains how to use Spring's org.springframework.util.StopWatch and Apache Commons Lang3 StopWatch to accurately measure and analyze Java code execution time, covering setup, basic usage, advanced features, thread‑safety considerations, and practical code examples for both libraries.
This article explains Spring's @Transactional annotation, detailing propagation behaviors, rollback rules, common pitfalls such as self-invocation and non‑public methods, and provides practical solutions using AOP proxies and AopContext to ensure proper transaction management in Java backend applications.
This article describes a backend solution that uses Redis for configurable rate‑limiting and interface switches, and Hystrix for circuit‑breaking, detailing the requirements, AOP‑based approach, and full Java code implementation for managing non‑core query overloads.
This article demonstrates how to create custom Spring events, define listeners, publish events, and enable asynchronous handling with @EnableAsync and @Async annotations, providing complete code examples and test results for both synchronous and asynchronous scenarios in a Spring Cloud Alibaba micro‑service environment.
This article explores the complete lifecycle of graceful shutdown for Java server applications, detailing how operating‑system signals, JVM shutdown hooks, and framework‑level mechanisms in Spring, Dubbo, and Netty collaborate to safely stop services while preserving in‑flight requests and resources.
This article introduces a Redis lazy‑loading caching strategy combined with Guava local cache, presents design diagrams and Java code examples, analyzes its advantages and disadvantages, and discusses suitable scenarios such as precise query workloads and micro‑service architectures.
This article introduces Spring Expression Language (SpEL), explains its common syntax, demonstrates quick-start examples, shows real-world usage with AOP monitoring, and outlines its internal implementation, providing a concise guide for backend developers working with Spring.
This article provides a detailed tutorial on Activiti 7 workflow engine, covering workflow fundamentals, BPMN modeling, environment setup, Maven dependencies, configuration files, process deployment, instance creation, task querying and completion, process definition management, resource extraction, and historical data inspection, all illustrated with Java code examples.
This article explains how MapStruct simplifies Java object‑to‑DTO mapping by defining mapping rules, demonstrates various features such as default methods, abstract mappers, multiple parameters, @MappingTarget updates, handling of fields without getters/setters, Spring integration, and custom type conversions with clear code examples.
This article explains how to solve cross‑server WebSocket communication in a distributed Java application by using a message queue (Redis or Kafka) to broadcast messages, storing user‑node mappings, and providing complete Spring configuration, code examples, and a demo page for end‑to‑end testing.
This article explains the fundamentals of RPC, describes the components involved in a basic remote call, and provides a complete Java implementation using Spring, custom XML configuration, Netty for network communication, and Zookeeper for service registration and discovery, complete with server and client code examples.
This article explains Spring's core.convert package, the ConversionService API, Formatter SPI, default and custom formatters, annotation-based formatting, and how to configure and use them in Spring MVC and Spring Boot applications.
This article explains how to leverage Spring's org.springframework.util.StopWatch and Apache Commons Lang3 StopWatch for precise Java performance measurement, covering setup, usage examples, source code insights, important considerations, and practical code snippets for both libraries.
This article explains how to mask sensitive fields such as ID numbers, phone numbers, and addresses in Java APIs by creating a custom @Sensitive annotation, defining masking strategies, implementing a Jackson serializer, and testing the solution with a Spring REST controller, providing complete code examples and sample output.
This article explains why the @Transactional annotation in Sharding-JDBC can roll back across multiple databases in some scenarios, clarifies the cases it truly supports, details the internal rollback implementation, and outlines the situations where local transactions cannot guarantee distributed consistency.
This article explains the principles and implementations of Java's built‑in SPI, Dubbo's enhanced SPI, and Spring's SPI mechanisms, compares their designs, walks through concrete code examples, and shows how they can be applied for dynamic extension in real projects.
This article explains the architecture and implementation of a permission system that provides front‑end menu rendering, unified single sign‑on, RBAC‑style permission management, and backend request authorization using Java and Spring technologies.
This article explains the fundamentals of database transactions, the ACID properties, Spring's @Transactional support, various propagation behaviors and isolation levels, and provides practical code examples for both declarative and programmatic transaction management in Java backend development.
This article explains how Spring's @Scheduled annotation works, covering configuration options like cron, fixedDelay and fixedRate, the internal processing by ScheduledAnnotationBeanPostProcessor, method reflection, task registration with ScheduledTaskRegistrar, and the underlying execution using ThreadPoolTaskScheduler and ScheduledThreadPoolExecutor.
This article presents a one‑stop solution that uses dynamic proxies, Spring extensions, and Dubbo generic invocation to let overseas applications call domestic Dubbo services via HTTP without refactoring existing callers, reducing workload and eliminating previous drawbacks.
This article demonstrates how to design a simple Calculator interface, provide both annotation‑based and reflection‑based implementations, and achieve hot deployment by loading user‑supplied JAR files at runtime, including dynamic bean registration and removal in a Spring container.
This article provides a comprehensive tutorial on implementing Single Sign-On using the CAS (Central Authentication Service) framework, covering the concepts of SSO and CAS, required development environment, server-side deployment, client configuration, and end‑to‑end testing with detailed code examples.
This article provides an in‑depth tutorial on Activiti 7 workflow management, covering workflow concepts, system architecture, BPMN modeling, environment setup, Maven dependencies, database configuration, deployment methods, process execution, task handling, and historical data retrieval for Java backend development.
This article explains how to replace repetitive try‑catch blocks in Java Spring applications with a clean, centralized exception handling strategy using @ControllerAdvice, custom Assert utilities, and enum‑based error codes, while also showing how to return consistent error responses across services.
This article explains what circular dependencies are in Spring, describes the three‑level cache mechanism (singletonObjects, earlySingletonObjects, singletonFactories), shows how it resolves singleton bean cycles, and outlines scenarios where the cache cannot break the dependency, such as constructor injection and prototype beans.
This article provides an in‑depth tutorial on Spring Validation, covering basic usage, dependency configuration, requestBody and requestParam validation, unified exception handling, advanced techniques such as group, nested, and collection validation, custom validators, programmatic validation, fail‑fast mode, and the underlying implementation mechanisms.
This article explains how Spring developers can explicitly control bean instantiation order by using dependency‑injection annotations such as @Autowired, @Resource, @Inject, and the @DependsOn annotation, detailing the underlying processors and showing code examples for each mechanism.
To pre‑warm business data before a Spring web service accepts requests, the article explains two approaches—implementing the SmartLifecycle interface with proper phase ordering and using a ContextRefreshedEvent listener—while highlighting code examples, execution timing, and cautions against asynchronous overrides.
This comprehensive guide walks through Spring’s fundamentals—including IoC, DI, core modules, common annotations, AOP concepts, transaction management, MVC workflow, and Spring Boot auto‑configuration—while also covering advanced topics such as bean lifecycle, circular dependencies, proxy mechanisms, and an introduction to Spring Cloud.
This guide explains Spring’s Assert utilities and a comprehensive set of core helper classes—including ObjectUtils, StringUtils, CollectionUtils, FileCopyUtils, ResourceUtils, StreamUtils, ReflectionUtils, AopUtils, and AopContext—detailing their purpose, typical use cases, and providing concise code examples for each method.
SPI (Service Provider Interface) is a service discovery mechanism used in Java, Spring, and Dubbo that loads implementations via configuration files, enabling runtime extensibility, decoupling, and plug‑in architecture, with examples ranging from custom interfaces to MySQL drivers and Dubbo extensions.
This article details Meituan's internal Sonic IDEA plugin, explaining hot‑deployment concepts, why they matter, the technical challenges, and Sonic's architecture—including agents, instrumentation, class reloading, Spring Bean/XML/MyBatis reloads, and real‑world deployment experience—showing how code changes can become effective in seconds instead of minutes.
This article explains how to implement the Singleton pattern in Java using both an enum‑based approach and a static inner‑class technique, providing thread‑safe examples from Spring Data JDBC and MyBatis along with Maven dependency snippets and detailed code illustrations.
This article explains how SQL injection can exploit a Java Spring course‑selection system by concatenating user input into SQL statements, demonstrates various injection techniques such as always‑true conditions and UNION queries, and provides multiple defensive measures including prepared statements, type checking, permission restrictions, and request‑parameter filtering.
Explore multiple Spring bean injection techniques—including XML configuration, annotation-driven @Configuration/@Bean, @Import, FactoryBean, and BeanDefinitionRegistryPostProcessor—through clear explanations, code samples, and practical examples, highlighting their advantages, drawbacks, and how to integrate them into a Spring application.
This article demonstrates how to dramatically speed up updating tens of thousands of records in a Spring‑MyBatis application by switching from automatic per‑operation commits to manual transaction control, applying multithreaded processing, tuning the Hikari connection pool, and using SQL UNION‑based batch updates.
This article explains how Spring Kafka’s KafkaMessageListenerContainer and ConcurrentMessageListenerContainer work, details their start-up process and internal consumer threads, shows how @KafkaListener bridges business logic, and provides configuration examples for single‑message and batch processing in Spring Boot.
This article explores twelve practical multithreading use cases in Java, ranging from simple scheduled tasks and listeners to Excel imports, remote call aggregation, user context handling, MDC logging, high‑concurrency simulation, Kafka message processing, atomic counters, and delayed jobs, providing code examples and best‑practice tips for each scenario.
This article discusses practical techniques for Java developers, covering bean conversion using DTOs and Spring utilities, validation with JSR‑303, leveraging Lombok for cleaner code, applying design patterns, and systematic refactoring to improve readability, maintainability, and overall code quality in backend projects.
This article explains the purpose and usage rules of Spring's @Async annotation, compares built‑in executors, demonstrates how to enable @Async, and provides detailed examples of custom thread‑pool configurations, multiple pool management, and important source‑code analysis for robust asynchronous processing in Java backend applications.
This article introduces MapStruct’s new Spring extension, shows how to replace manual BeanUtil conversions with generated mappers, explains the Spring Converter interface, and demonstrates custom configuration and integration with ConversionService for seamless DTO/VO/PO transformations in Java backend projects.
This article explains how to replace manual BeanUtil mapping with MapStruct, leverage Spring's Converter interface, and use the MapStruct Spring Extensions plugin to automatically register mappers with ConversionService, including custom adapter configuration and integration of built‑in Spring converters.
This article explores the concept of fully interface‑based domain modeling, demonstrates how to design domain objects as interfaces, shows repository implementations for JPA, MyBatis and Elasticsearch, discusses association handling, and explains how such designs enable seamless switching between monolithic, clustered and microservice deployments.
This article explains how MapStruct, a Java annotation‑processor library, can automatically generate mapper implementations to convert between entities and DTOs, covering basic usage, default methods, abstract classes, multiple source parameters, update operations, handling fields without getters/setters, Spring injection and custom type conversions.
This article demonstrates how to create a request‑logging aspect in Spring Boot using AOP annotations, shows code for pointcuts, advices, high‑concurrency optimizations, exception handling, and trace‑ID propagation, and explains the underlying concepts and practical tips.
This article provides an in‑depth tutorial on Spring Validation, covering basic usage, dependency setup, requestBody and requestParam validation, DTO constraints, group and nested validation, collection handling, custom validators, programming‑style validation, fail‑fast mode, and the underlying implementation mechanisms in Spring MVC.
This article explores practical Java backend techniques, including IDE selection, domain vs entity naming, DTO conversion strategies with BeanUtils and custom interfaces, validation with JSR‑303, Lombok shortcuts, builder patterns, static constructors, and design‑pattern considerations, offering concrete code examples and refactoring tips for seasoned developers.
Field injection in Spring looks concise, but it introduces hidden dependencies, violates the Single Responsibility Principle, hampers immutability, and tightly couples code to the DI container; the article compares constructor, setter, and field injection, explains their drawbacks, and recommends using constructors for mandatory dependencies and setters for optional ones.
This Spring AOP tutorial explains how to modularize cross‑cutting concerns such as timing by defining an aspect with @Before, @After, @AfterReturning, @AfterThrowing and @Around advice, demonstrates refactoring a calculation service, and compares Spring’s proxy mechanisms to a custom JDK dynamic proxy implementation.
This article explains the background, concepts, and implementation details of Aspect‑Oriented Programming in Java, covering joinpoint interface design, advice abstraction, static and dynamic weaving, and how Spring AOP applies these principles with illustrative code and diagrams.
This article explains how Spring's three‑level cache (singleton, early‑singleton, and singleton‑factory caches) works together with bean post‑processors to break circular dependencies and correctly create AOP proxies, while also showing how to disable circular references when needed.
This article compares native JDK ScheduledExecutorService, Spring Task, Redis‑based approaches, and popular distributed scheduling frameworks such as Quartz, Elastic‑Job, LTS, and XXL‑Job, providing code examples, usage scenarios, advantages, and best‑practice recommendations for implementing reliable timed jobs in microservice environments.
This article explains three common situations where Spring's @Transactional annotation becomes ineffective—non‑public methods, internal self‑calls, and swallowed exceptions—detailing the underlying proxy mechanism, code examples, test results, and practical workarounds to ensure proper transaction management.
This article provides a detailed overview of the most frequently used Spring annotations—including core, MVC/REST, Boot, stereotype, data access, scheduling, and testing annotations—explaining their purposes, usage rules, and providing Java code examples for each.
This article demonstrates how to create a Spring AOP request‑logging aspect that captures IP, URL, HTTP method, class method, parameters, results and execution time, and extends it with high‑concurrency handling, error logging, and TraceId propagation for better traceability.
This article explains how Spring implements broadcast and listener functionality through ApplicationEventPublisher and ApplicationListener, analyzes the underlying bean post‑processor workflow, and provides complete source‑code examples for custom events, publishers, listeners, and a REST client to demonstrate end‑to‑end event handling.
This article explains how to create a Spring AOP request‑logging aspect, covering basic pointcut and advice definitions, parameter extraction, high‑concurrency optimizations with unified JSON logs, exception handling, and adding traceId support for end‑to‑end request tracing.
This article explains how to implement single-node scheduled tasks using JDK's ScheduledExecutorService and Spring @Scheduled, compares Redis‑based approaches with ZSet and key‑space notifications, and reviews popular distributed scheduling frameworks such as Quartz, elastic‑job‑lite, LTS, and XXL‑Job for microservice environments.
This article explores the precise moment a Spring @Transactional transaction is committed relative to a surrounding lock release, revealing that commits occur after the method finishes, and demonstrates how to verify this through source code inspection, debugging techniques, and proper lock‑usage to prevent overselling.
This article explains how to prevent duplicate user requests on the server side by leveraging unique request IDs or business‑parameter MD5 hashes with Redis, provides Java helper utilities, code examples, and practical tips for handling time‑related fields and atomic SETNX operations.
This article presents a design pattern for a unified, annotation‑driven HTTP client in a Spring‑based payment system, detailing custom annotations, dynamic proxy enhancement, and bean registration via FactoryBean and ImportBeanDefinitionRegistrar, with complete code examples and a summary of key concepts.
This article explains three common reasons why the @Transactional annotation may not work in Spring—non‑public methods, self‑invocation, and catching exceptions—provides code examples for each case, and details the underlying proxy and transaction management mechanisms to help developers resolve the issues.
This article details the discovery, official announcement, prerequisite conditions, and step‑by‑step reproduction of the critical Spring Framework remote code execution vulnerability (CVE‑2022‑22965), including exploit payloads, JSP backdoor creation, and practical mitigation insights.
A recent Spring Framework 0‑day remote code execution vulnerability, caused by unsafe use of SerializationUtils#deserialize, affects Java versions above 8, is rated dangerous by security analysts, and highlights the risks of indiscriminate JDK upgrades.
This article compares traditional object creation with Spring’s dependency injection, demonstrating how injecting DAO beans via XML configuration decouples service and data layers, includes Java code examples, test results, and visual analogies of gear systems to illustrate reduced coupling.
This article explains the officially announced Spring Framework remote code execution vulnerability CVE‑2022‑22965, outlines the affected environments, provides upgrade paths for Spring and Spring Boot, and shares safe code‑based mitigation techniques for developers.
This article reveals a newly disclosed Spring framework RCE 0‑day vulnerability caused by unsafe Java serialization, rates it as dangerous, explains why Java 8 remains unaffected, and warns developers against indiscriminate JDK upgrades while comparing it to the Log4j2 incident.
The article investigates the circulating rumors of a massive Spring framework vulnerability, clarifies its actual scope—affecting Java 9+ projects—and explains why the alleged CVE differs from official reports, while warning readers to rely only on verified security advisories.
The author humorously explores a newly disclosed Spring framework RCE 0‑day vulnerability caused by Java serialization, explains why systems running JDK 8 or earlier are unaffected, compares its impact to Log4j2, and warns against indiscriminate JDK upgrades.
This guide explains the Spring SPEL injection flaw, how to determine if your Java application is affected by checking JDK version and Spring usage in WAR or JAR packages, and provides official upgrade steps along with temporary WAF and code‑level mitigations.
This article explains why OpenFeign asynchronous calls fail due to lost request context, demonstrates a RequestInterceptor to propagate JWT tokens, and shows how to capture and set RequestAttributes in CompletableFuture tasks so that async Feign calls succeed without triggering Sentinel degradation.
This article explains the similarities and differences between Spring's @Autowired and the JSR‑250 @Resource annotations, covering their packages, injection mechanisms, usage on fields and setters, configuration options, IDE warnings, and best‑practice recommendations for bean injection in Java backend development.
This article explains the limitations of HTTP for real‑time communication, compares WebSocket with polling, long‑polling, streaming and SSE, outlines WebSocket's benefits and typical use cases, and then details how STOMP complements WebSocket within Spring's messaging framework, including configuration and message flow.
This article provides a comprehensive guide to Spring's most useful utility classes—including Assert, ObjectUtils, StringUtils, CollectionUtils, FileCopyUtils, ResourceUtils, ReflectionUtils, and AopUtils—detailing their purpose, key methods, and practical code examples for backend developers.
This article explains how to standardize API responses in a Spring backend by defining a JSON result structure, designing status codes, using @ResponseResult annotations, interceptors, and controller advice to automatically wrap results, while also discussing optimization and best‑practice considerations.
This article demonstrates how to create a lightweight Spring‑style IoC container in Java by parsing a properties file for XML‑like configuration, implementing annotation‑driven bean registration with a custom @Bean annotation, and adding automatic field injection using a custom @Autowired annotation, complete with full source code examples.
The article breaks down Spring's circular dependency problem, explains its three typical forms, details the three‑level cache mechanism with code snippets, walks through the step‑by‑step resolution process, and lists scenarios where Spring cannot resolve such dependencies.
This article explains Spring's bean lifecycle, the three‑level cache mechanism (singletonObjects, earlySingletonObjects, singletonFactories) used to break circular dependencies, the role of Aware interfaces and BeanPostProcessor, and why a second‑level cache is essential when AOP proxies are involved.
When a Spring @Bean is defined with multiple names, only the first name becomes the bean identifier while the others become aliases that are ignored by type‑based Map injection, causing dynamic data‑source routing to fail unless the aliases are manually added back into the map.
This article explains how to enhance Spring Cache by creating custom cache annotations, replacing the costly KEYS command with SCAN in a rewritten DefaultRedisCacheWriter, and dynamically registering RedisCacheManager beans to support per‑module TTL and transaction‑aware caching, all illustrated with full Java code examples.
This article explains how Spring's @Transactional annotation works by leveraging AOP and dynamic proxies, detailing the bean post‑processor, pointcut definition, proxy creation, interceptor chain, TransactionInterceptor logic, and the transaction commit/rollback process with illustrative code snippets and diagrams.
This roundup covers recent Java ecosystem developments, including the promotion of the Value Objects (Preview) JEP to candidate status, release notes for JDK 18 and early‑access JDK 19 builds, multiple Spring project updates such as Spring Boot 2.7.0‑M1, Spring Data 3.0‑M2 with ListCrudRepository, Spring Security enhancements, as well as Quarkus 2.7.2.Final and a new early‑access version of JReleaser adding Windows resources to jpackage.
This article explains why Spring’s circular dependency problem only occurs with singleton beans, how constructor versus setter injection affects resolution, and why Spring uses a three‑level cache (singletonObjects, earlySingletonObjects, singletonFactories) to expose incomplete beans and support proxy creation without breaking the bean lifecycle.
The article details Meituan's internal Sonic IDEA plugin for remote and local hot deployment, explaining why hot deployment is needed, its architecture, instrumentation techniques, DCEVM integration, file‑watching, class reloading, and support for Spring Bean, Spring XML and MyBatis, along with adoption statistics and performance benefits.
This article explains what streaming queries are, why they save memory compared to pagination, details the MyBatis Cursor interface and its methods, demonstrates how to implement streaming queries with code examples, and presents three solutions—using SqlSessionFactory, TransactionTemplate, and @Transactional—to keep the database connection open and prevent cursor‑closed errors.
This article explains how to modify Spring's @Async annotation so that its value attribute can resolve placeholders or SpEL expressions, demonstrates a working demo, shows the required code changes using EmbeddedValueResolver, and shares debugging tricks and related Java language features.
This article walks through the fundamentals of Spring’s IoC container by manually implementing a lightweight version, covering concepts such as IOC, DI, bean definitions, resource loading, bean registration, and a simple BeanFactory with example code and a test demonstrating singleton caching.
The article sarcastically critiques the over‑engineered nature of enterprise Java projects, illustrating how simple tasks become tangled in excessive classes, interfaces, factories, dependency‑injection frameworks, XML configurations, massive JARs, and IDE bloat, ultimately leading to deployment failures due to environment mismatches.
This article explains why Spring MVC controllers are singleton by default, demonstrates the thread‑unsafe behavior of using instance fields, shows how applying @Scope("prototype") changes the behavior, and provides practical recommendations such as avoiding mutable fields, using prototype scope or ThreadLocal for safe controller design.
This article explains how MyBatis streaming queries work via the Cursor interface, why keeping the database connection open is essential, and presents three practical solutions—using SqlSessionFactory, TransactionTemplate, or @Transactional—to correctly handle streaming data in Spring applications.
Learn how to resolve WebSocket session sharing issues in load‑balanced Java applications by leveraging Redis’s publish/subscribe mechanism and Spring Session, with step‑by‑step configuration, code examples, and deployment instructions for multiple distributed environments.
After upgrading a core component, a previously synchronous domain event in Spring became asynchronous, causing runtime errors; this article explains the underlying mechanism, shows the relevant source code of SimpleApplicationEventMulticaster, and clarifies how the presence or absence of a configured thread pool determines whether events are processed synchronously or asynchronously.
This post shares a comprehensive Java interview handbook containing over 1,000 questions covering MyBatis, Zookeeper, Dubbo, Redis, MySQL, concurrency, Spring, Kafka, micro‑services and more, hosted on GitHub with 30K+ stars, and explains how to obtain the latest PDF via a WeChat QR code.
The article explains that adding Spring Cloud's @RefreshScope annotation to beans annotated with @Service or @Component makes the bean definition synthetic, causing Spring's BeanPostProcessor to skip those beans and leading to processing failures.
The article describes a solution that automatically triggers interface test cases after a service deployment by listening to deployment‑success MQ messages, dynamically invoking TestNG with service‑specific IPs, and integrating Spring bean registration to simplify test code while handling dynamic nodes, reporting, and common pitfalls.
This article explains several often‑confused Spring annotations—including the differences between @Component and @Bean, the injection behaviors of @Autowired versus @Resource, the roles of @Component, @Repository, @Service, and @Controller, the purpose of @Configuration and @ControllerAdvice, and provides practical code examples for each.
This article outlines ten typical concurrency pitfalls in Java—including SimpleDateFormat thread‑safety, double‑checked locking flaws, volatile atomicity limits, deadlocks, lock release issues, HashMap race conditions, default thread‑pool misuse, @Async thread explosion, spin‑lock CPU waste, and ThreadLocal memory leaks—providing explanations, code examples, and practical solutions for each.
This article analyzes a Spring transaction rollback issue caused by the use of pattern‑based exception matching, explains why certain custom exceptions trigger unexpected rollbacks, traces the problem through source code and GitHub issues, and describes how the Spring team fixed it with type‑safe rollback rules and documentation updates.
