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.
This article provides a comprehensive guide to the Spring framework, covering its core modules, the concepts of Inversion of Control and Aspect‑Oriented Programming, various container implementations, proxy mechanisms, bean lifecycle, design patterns, MVC architecture, Spring Boot, Spring Cloud, and common annotations for Java backend development.
This article explains how Spring resolves circular dependencies for singleton beans using a three‑level cache, contrasts it with prototype limitations, provides a minimal container implementation that mimics the mechanism, and draws an analogy to the classic two‑sum algorithm to illustrate the core caching principle.
This article demonstrates how to create a Spring AOP request‑logging aspect that captures request parameters, response data, execution time, and error information, while also handling high‑concurrency scenarios and integrating traceId support for easier log tracing.
This article examines the drawbacks of lengthy if‑else statements in Java payment services, explains how they violate the Open/Closed and Single Responsibility principles, and presents multiple refactoring techniques—including custom annotations, dynamic bean naming, template methods, strategy‑factory, and chain‑of‑responsibility patterns—to produce cleaner, more maintainable backend code.
An in‑depth look at the latest Java Top‑200 project rankings reveals Spring’s ecosystem as the de‑facto standard, while contrasting tools such as Gradle versus Maven, Kafka versus Pulsar, Spring Security versus Shiro, and many others, highlighting performance, adoption and community strength across the backend landscape.
This article examines whether Service and DAO layers in Spring projects truly require interfaces, debunks common justifications, explores alternative project structures for single and multiple implementations, and offers practical guidelines on when to use or omit interfaces.
The author reflects on returning to Java after three years, arguing that despite the rise of containers and micro‑services, Java’s performance, threading model, and mature ecosystem keep it relevant, while criticizing Spring’s complexity and advocating a simple, KISS‑driven approach.
This guide explains the concepts, implementation steps, configuration examples, and key differences between Servlet Filters and Spring MVC Interceptors, helping developers choose the right tool for request preprocessing, logging, and access control in Java web applications.
This article explains what a circular dependency is in Spring, outlines the conditions under which Spring can resolve such cycles, and details the three‑level cache mechanism that enables bean creation, property injection, and AOP proxy handling to break the loop.
This article examines whether a Service layer in a Spring‑based backend project truly requires an interface, debunks common justifications, proposes practical development workflows, and outlines the advantages and drawbacks of using or omitting interfaces in various architectural scenarios.
This article explains the functional differences, recommended usage scenarios, and IDE warnings for Spring's @Autowired and @Resource annotations, showing how constructor, setter, and field injection affect code quality, testability, and framework portability.
This article explains the concept of streaming queries, introduces MyBatis's Cursor interface, demonstrates how to use it in Spring MVC controllers, and provides three concrete solutions—using SqlSessionFactory, TransactionTemplate, and @Transactional—to keep the database connection open and avoid cursor‑closed errors.
This article explains why Spring beans are not inherently thread‑safe, compares the singleton and prototype scopes, shows how stateless beans can be safe, demonstrates the impact of static fields and injected beans, and provides practical code examples and recommendations for achieving thread safety in Spring applications.
This article explores nine core design patterns implemented in Spring—simple factory, factory method, singleton, adapter, decorator, proxy, observer, strategy, and template method—detailing their implementation mechanisms, underlying principles, code examples, and practical significance for building loosely coupled, extensible Java applications.
This article examines whether a Service layer in a Spring‑based application truly requires an interface, analyzes common arguments for and against using interfaces, explores project structuring options, and offers practical recommendations based on real‑world development experience.
This article explains Spring Retry's architecture, how @EnableRetry, @Retryable, @Backoff and @Recover work together, details the available retry and back‑off policies, and walks through the core implementation using RetryTemplate and interceptors to provide flexible, AOP‑based retry handling in Java backend applications.
This article explains the fundamentals of Aspect‑Oriented Programming (AOP) in Spring, describes its core concepts and terminology, and provides step‑by‑step code examples for creating pointcuts, advices, and custom annotations, while also detailing the use of common AOP annotations such as @Pointcut, @Around, @Before, @After, @AfterReturning and @AfterThrowing.
This article shares practical techniques for handling large transactions in Spring-based backend systems, covering why @Transactional can cause issues, how to use programmatic transactions, move queries outside transactions, avoid remote calls, limit data volume, execute non‑transactional operations, and leverage asynchronous processing.
This article explains the concept of streaming queries in MyBatis, introduces the Cursor interface, demonstrates common pitfalls with connection closure, and provides three practical solutions—using SqlSessionFactory, TransactionTemplate, or @Transactional—to safely retrieve large result sets without exhausting memory.
This article explains how to configure Spring transaction isolation levels and propagation behaviors, illustrates the effects of dirty read, non‑repeatable read, and phantom read with examples, and provides practical code solutions for handling rollback of failed sub‑tasks and self‑invocation issues.
This article explains the real JDBC transaction methods, clarifies common misconceptions about transaction states in MyBatis, details the MyBatis Transaction and TransactionFactory interfaces, and explores special scenarios such as auto‑commit false, missing commit or close, with concrete code examples.
This article compares Spring and Spring Boot, explaining their fundamental concepts, Maven dependencies, MVC and security configurations, template engine setup, startup mechanisms, and packaging options, while providing practical code examples to help Java developers choose and migrate between the two frameworks.
This article explains the limits of annotation inheritance in Java, demonstrates why subclass methods cannot automatically inherit parent annotations, and shows how to use @Inherited, Spring's AnnotatedElementUtils, and find/get semantics to retrieve inherited annotations effectively.
The article explains how long‑running database transactions can exhaust connection pools, block threads, and cause widespread service failures, then offers practical strategies—including keeping transactions short, removing RPC calls, enhancing monitoring, and reviewing code—to detect and prevent these high‑risk issues.
This article provides a comprehensive overview of the Spring framework, explaining its IoC and AOP core, architectural layers, key advantages such as decoupling and declarative transactions, bean scopes, lifecycle settings, and practical object‑creation methods for Java backend development.
This article explains the AOP mechanism behind Spring's @Transactional, why only unchecked exceptions trigger automatic rollbacks, illustrates common pitfalls with code examples, and provides practical fixes such as using rollbackFor or manually marking the transaction for rollback.
This article explains how to create and use custom Java annotations together with Spring AOP to implement unified logging, method‑level parameter validation, and other cross‑cutting concerns, providing practical code examples and best‑practice recommendations for backend developers.
This article explains why Spring AOP advice does not trigger when a method calls itself via this, demonstrates how to reproduce the problem, and provides a solution using AopContext.currentProxy() together with proper proxy configuration to ensure the aspect executes correctly.
This article explains MyBatis-Plus's key features, shows how to add Maven dependencies, demonstrates the built‑in batch‑insert API, and provides step‑by‑step code to extend MyBatis‑Plus with a custom mapper and service for fast MySQL batch inserts.
This page continuously gathers and organizes over 200 Java backend interview Q&A articles, covering topics such as Spring, Redis, MySQL, concurrency, design patterns, and system design, providing a valuable resource for candidates to review before interviews.
This article demonstrates how to create a Spring AOP request‑logging aspect that captures request details, execution time, and errors, optimizes log output for high‑concurrency environments, and integrates trace‑ID tracking for easier debugging across distributed services.
This article explains how to create and use custom Java annotations in Spring for field validation, permission checks, and caching, including the definition of annotation types, associated validator and interceptor classes, and practical usage examples with code snippets.
Spring provides two IoC containers—BeanFactory and ApplicationContext—each with distinct loading strategies, features, and registration behaviors; this article demonstrates their differences through practical code examples, highlighting lazy versus eager loading, automatic post‑processor registration, and why ApplicationContext is generally preferred for enterprise applications.
By profiling the idle‑local Java backend, the author cut build, deployment, and startup times by over 30 seconds per cycle through asynchronous Spring bean initialization, selective dependency pruning, layered Docker image construction, and streamlined shutdown, demonstrating a comprehensive, reusable optimization strategy for faster releases.
This article examines whether every Service and DAO class in a Spring‑based backend should implement an interface, evaluates the common arguments for using interfaces, explains why they often do not hold up, and proposes practical structuring and development approaches for projects that may or may not need multiple implementations.
This article explains how ThreadLocal works internally, demonstrates its typical use in a Spring single‑sign‑on interceptor, analyzes the source code of ThreadLocal and ThreadLocalMap, and reveals the conditions under which ThreadLocal can cause memory leaks, offering practical guidance to avoid them.
This article explores why unit testing is essential, how to conquer the psychological obstacles that prevent developers from writing tests, and provides practical methodologies such as TDD, BDD, the test pyramid, and the Fixture‑Scenario‑Case pattern with concrete Java examples.
