The article explains how Lombok’s @Data annotation generates getter and setter methods with a lowercase first letter for camel‑case fields, causing Jackson to serialize JSON property names in all lowercase, and offers three fixes: write methods manually, use @JsonProperty, or rename fields to avoid lower‑upper patterns.
This article explains why large file downloads can fail on unstable networks, how to use HTTP Range headers and status codes for resumable downloads, and provides a complete SpringBoot implementation—including controller, service logic, and range‑parsing code—to enable reliable partial content delivery.
The article outlines the most impactful Java 25 enhancements—including compact object headers, generational Shenandoah GC, ahead‑of‑time compilation, JFR improvements, security updates, and the removal of 32‑bit support—explaining how each change boosts performance, safety, and observability for developers.
Spring Debugger’s new remote debugging feature lets developers inspect Spring beans, execute SQL, view configuration, and analyze transactions on running applications without using Java agents, leveraging container thread models like Tomcat’s persistent workers, with simple JDWP setup and a few limitations.
This article explains why raw collections are unsafe, how Java generics enforce compile‑time type safety, reduce casting, improve code readability, and boost performance, and it walks through generic interfaces, collections, custom generic classes, inheritance rules, diamond syntax, and common restrictions with concrete code examples and diagrams.
A payment service showed successful orders but no data in the database, leading to lock timeouts; the root cause was a hidden missing commit in a special code path that polluted the connection pool, causing other services to inherit an uncommitted transaction and fail intermittently.
This article explains how the @CacheEvict annotation in Spring Cache can be used to delete specific cache entries or clear entire caches, detailing its parameters such as value, allEntries, and beforeInvocation with a concrete code example.
The article explains how Spring Cache, introduced after Spring 3.1, uses the @Cacheable annotation to declaratively cache method results, detailing each attribute such as cacheNames, key, keyGenerator, and unless, with code examples illustrating key generation and conditional caching.
The article explains that @CachePut serves as a trigger to update or add cache entries in Spring Cache, contrasting its behavior with @Cacheable, detailing execution flow, handling of null results, and the recommendation against using both annotations on the same method.
This article walks through the complete development of a minimal Model Context Protocol (MCP) server using Spring Boot 3 and Server‑Sent Events, illustrating how OpenSpec drives the workflow from proposal and task breakdown to design, implementation, testing, and integration with Claude Code.
This article compares ten community‑sourced approaches for representing monetary values in Java, explaining when a simple Long, a precise BigDecimal, a String, custom wrappers, Protobuf tricks, leadership directives, AI assistance, or even minimal integer types are appropriate, and why each choice matters.
This article explains how aspect‑oriented programming (AOP) addresses cross‑cutting concerns by defining joinpoint interfaces, describing their design, illustrating Java examples, and comparing static and dynamic weaving techniques used in frameworks like Spring.
This article explains why Java generics were introduced, demonstrates how they improve type safety and reduce casting through concrete examples with generic classes, interfaces, collections, custom generic methods, and highlights common pitfalls such as generic arrays and static methods.
A payment service failed to insert orders despite successful payments, showing no errors, occasional lock timeouts, and intermittent success, which was traced to a missing transaction commit that polluted reused connections, causing unrelated business failures until the bug was fixed and preventive measures were added.
JetBrains' IntelliJ IDEA 2026.1 EAP 3 introduces a long‑awaited feature that moves deleted files to the system recycle bin instead of permanently erasing them, while also delivering a host of Spring, Java, Kotlin, editor, AI, platform, and performance enhancements for developers.
This article walks through converting a Maven‑based Java Spring Boot project (mall‑tiny) to Gradle, explains Gradle's key features and plugins, provides step‑by‑step setup with screenshots, shows the full build.gradle file, and compares build times to demonstrate Gradle's speed advantage.
This tutorial explains how to add the EasyCaptcha library to a Spring Boot 3.5.0 project, covering dependency setup, generating various captcha types (arithmetic, Chinese, font‑based), converting them to images or Base64, and integrating the captcha flow with Redis in a Spring MVC controller.
This article introduces an open‑source MyBatis‑Plus dynamic‑table starter, explains why dynamic table names are needed for large‑scale data, outlines its key features, provides step‑by‑step installation and quick‑start instructions, demonstrates advanced usage, debugging tips, FAQs, and real‑world scenarios.
This article demonstrates how to encapsulate common RedisTemplate operations—such as deleting single or multiple keys, setting expiration, checking existence, and performing String and Hash CRUD actions—by providing concrete Java code examples and step‑by‑step method implementations.
This article explains the common Redis caching tools, introduces Spring Data Redis's bound operation APIs, and provides step‑by‑step configuration examples for RedisTemplate, helping developers choose and set up a Redis client in Java applications.
This guide shows how to break down tangled Java services using Domain‑Driven Design and Command‑Query Responsibility Segregation, providing concrete terminology, layered diagrams, code examples, and step‑by‑step migration strategies to improve maintainability, performance, and team communication.
The article details Du Xiaoman's 2023 campus hiring salaries for Java backend roles, explains the significance of signing bonuses, shares a successful intern story, and provides in‑depth interview preparation covering thread pools, locks, AQS, CAS, SQL optimization, sharding, MVCC, and transaction isolation levels.
Maven 4, released at the end of 2025, introduces a 4.1.0 POM model, separates build and consumer POMs to flatten dependencies, adds explicit classpath‑jar and module‑jar artifact types, renames modules to subprojects, and implements a tree‑based lifecycle for true parallel builds, all while remaining backward compatible.
This article breaks down the interview focus points, core answer, deep analysis, code examples, and common pitfalls for ensuring RocketMQ messages never get lost, covering producer, broker, and consumer configurations, trade‑offs, and practical troubleshooting steps.
A production incident where payment requests succeeded but no order rows were inserted was traced to a missing commit in a special code path, causing a polluted connection to be reused by other services; the article details the debugging steps, root‑cause analysis, code fixes, and preventive measures.
This guide walks you through a fully open‑source, pure‑Java solution for converting uploaded .docx files to PDF in a Spring Boot application, covering library selection, Maven dependencies, a reusable utility class, controller implementation, and handling Chinese font issues on Windows and Linux.
JetBrains' IntelliJ IDEA 2026.1 EAP 3 introduces a long‑awaited feature that moves deleted files to the system recycle bin instead of permanently erasing them, while also delivering a host of Spring, Java, Kotlin, editor, AI, platform, and performance improvements aimed at modern remote and AI‑enhanced development workflows.
An in‑depth look at why Java’s TreeSet can trigger ConcurrentModificationException under high concurrency, exploring the red‑black tree’s non‑atomic operations, thread scheduling nuances, and how various concurrent set implementations—synchronized wrappers, read‑write locks, ConcurrentSkipListSet, CopyOnWriteArraySet, and custom designs—compare in performance and suitability.
This article explains the principles of Single Sign-On (SSO) and OAuth2.0, compares their workflows, outlines the four OAuth2.0 grant types, and clarifies terminology differences, providing clear step‑by‑step diagrams and practical examples.
The article explains how excessive if‑else logic harms maintainability in a business middle‑platform, introduces a flow‑engine and plugin‑extension approach to isolate code and support rapid business expansion, and demonstrates the design with the open‑source MemberClub project, including configuration, node definitions, execution principles and core Java implementation.
Learn how to convert user‑uploaded .docx files to PDF in a Spring Boot application using the pure‑Java docx4j library, covering solution comparison, Maven dependencies, utility class implementation, controller endpoint, and handling Chinese font issues on Windows and Linux.
The 2026.1 EAP 3 release of IntelliJ IDEA introduces several practical updates, including moving deleted files to the system recycle bin, deeper AI assistant integration with Roots and improved commands, automatic SQL dialect detection, enhanced Spring debugging, built‑in Git Worktree support, UI refinements, and numerous bug fixes across Java, Kotlin, Docker, and HTTP client features.
IntelliJ IDEA 2026.1 EAP 3 finally adds a recycle‑bin‑style file deletion, alongside dozens of enhancements for Spring, Java, Kotlin, editor experience, AI‑assisted completion, platform architecture, and performance, addressing long‑standing developer complaints and preparing the IDE for remote and AI‑driven workflows.
This article introduces MyPerf4J, a Java‑agent based, low‑overhead performance monitoring tool that provides real‑time metrics such as RPS, latency percentiles, memory usage and GC statistics, and explains how to install, configure, run and uninstall it in development and production environments.
This article explains Java's reflection mechanism, covering its main uses such as dynamic class loading, handling unknown types, accessing private members, and framework development, then walks through basic steps, a complete code example, and discusses its advantages and drawbacks.
The article explains that the “invalid source release: 10” error occurs because the IDE is set to JDK 10 while the system JDK is 8, and it walks through checking the JDK version and aligning IDEA project, compiler, and pom.xml settings to resolve the issue.
This article introduces Easy Work, a Java workflow engine, explaining its core concepts, showing how to define work units, compose complex sequential, parallel, and conditional flows, use breakpoints to pause execution, and construct workflows via JSON with complete code examples and repository links.
The Eclipse Foundation announced Jakarta EE 11, highlighting streamlined data access via the new Jakarta Data spec, support for Java 21 including virtual threads, modernized testing tools, deprecation of Managed Beans, and early certification of several enterprise servers, marking a major step toward cloud‑native Java development.
The author shares a workplace frustration about unfair performance metrics, then illustrates how a hidden 1024‑byte boundary bug led to a discussion of the classic “power‑of‑two” problem, providing clear bit‑wise logic, edge‑case handling, and ready‑to‑run Java code for detecting powers of two.
This article breaks down the interview focus points, core solution framework, underlying RocketMQ mechanisms, step‑by‑step remediation actions, common pitfalls, and a concluding strategy for handling message backlog through emergency scaling, consumer optimization, degradation, dead‑letter handling, and proactive capacity planning.
The article explains what occurs when a Redis distributed lock expires before a business operation completes, and details how Redisson’s watch‑dog mechanism automatically renews the lock, covering the underlying principles, configuration, code examples, and comparisons with alternative renewal approaches.
The article analyzes why many enterprises continue using JDK 8 despite newer releases like JDK 25, examining compatibility issues, stability, learning costs, third‑party library support, performance trade‑offs, commercial licensing, and toolchain considerations while offering migration guidance.
The article explains why returning a generic Result wrapper from a Java service layer breaks responsibility separation, harms reusability, complicates exception handling and testing, and obscures transaction boundaries, advocating for returning pure domain objects instead.
This guide explains how to integrate the asyncTool library into a Spring Boot project, configure custom thread pools, understand core interfaces like IWorker and ICallback, and use the provided Builder API to define serial, parallel, and mixed task flows with detailed code examples and best‑practice cautions.
The article explains that returning a Result wrapper from the Service layer mixes business logic with presentation concerns, leading to tighter coupling, reduced reusability, cumbersome error handling, harder testing, poorer DDD alignment, limited interface flexibility, and ambiguous transaction boundaries.
This tutorial shows how to implement graceful dynamic data source switching in SpringBoot by combining ThreadLocal with AbstractRoutingDataSource, configuring master/slave databases, adding a @DS annotation with AOP support, and enabling runtime addition of new data sources.
IntelliJ IDEA 2026.1 EAP 3 finally changes file deletion to use the system recycle bin, fixing a six‑year‑old request, while also delivering a long list of Spring, Java, Kotlin, editor, AI, platform, and performance improvements that enhance developer productivity and reliability.
This article explains how RocketMQ’s consumer model is fundamentally pull‑based with a long‑polling optimization that provides a push‑like experience, covering interview focus points, detailed mechanism, code examples, best practices, and common misconceptions.
This article walks through using the WeChat Mini Program media‑check API to identify risky audio, video, and image content, outlines three typical scenarios, explains platform rate limits, and provides a complete Java example with step‑by‑step code analysis.
Upgrading to Spring Boot 4 brings Jackson 3, which reorganizes packages, replaces ObjectMapper with JsonMapper, changes the default date format to ISO‑8601, and converts checked exceptions to RuntimeException, requiring developers to adapt code, adjust configurations, and understand the design rationale to avoid runtime bugs.
Upgrading to Spring Boot 4 brings Jackson 3, which introduces four major breaking changes—package reorganization, replacement of ObjectMapper with JsonMapper, a shift to ISO‑8601 date serialization, and the removal of checked exceptions—each explained with code examples, migration tips, and the rationale behind the design.
This article explains how a custom IntelliJ IDEA plugin can automate the creation of Maven multi‑module projects, turning a tedious half‑hour manual process into a 30‑second one‑click operation, and provides step‑by‑step installation, usage, customization, and troubleshooting guidance.
This article explains why Java’s finally block normally runs, dives into the compiler’s code‑copying, the bytecode exception table, JVM dispatch, JIT optimizations, and the design trade‑offs that ensure reliable cleanup while highlighting cases where finally may be skipped.
This article explains why a WeChat Mini Program needs an access_token, describes the token's 7200‑second validity, and provides a step‑by‑step Java implementation that builds the request URL, sends an HTTPS GET, parses the JSON response, and outlines a simple caching strategy.
This article explains the common reasons Spring transactions become ineffective or fail to roll back—such as wrong method visibility, final modifiers, self‑invocation, non‑Spring beans, multithreading, unsupported table engines, misconfigured propagation, swallowed exceptions, and improper rollback settings—while providing practical code solutions and best‑practice recommendations.
This article walks through building a pure‑Java DOCX‑to‑PDF converter in Spring Boot using docx4j, compares it with alternatives, shows Maven dependencies, provides a utility class and controller example, and explains how to resolve Chinese font garbling on both Windows and Linux.
The article explains how JetBrains' Spring Debugger plugin provides remote debugging for Spring applications without using Java agents, detailing the underlying thread‑model tricks, supported containers, practical features like bean inspection and SQL execution, and step‑by‑step JDWP configuration.
LiteFlow is a lightweight, open‑source Chinese rule engine that transforms tangled if‑else code into modular, hot‑deployable components using a simple EL DSL, offering high performance, multi‑language scripting, and visual orchestration for backend systems.
This article explains how to overcome the training‑deployment gap for Java‑based AI agents by introducing a cloud‑native, low‑intrusion online training pipeline built on AgentScope Java and Trinity‑RFT, detailing architecture, configuration, custom selection and reward strategies, and showing measurable accuracy gains on a SQL‑Agent benchmark.
This article examines the core challenge of giving large‑language‑model agents many abilities while keeping context size limited, compares three common loading strategies, introduces a progressive‑disclosure skill mechanism with three loading layers, and details its implementation, benefits, limitations, and suitable use cases in AgentScope‑Java.
This article first presents a quirky roundup of Chinese companies' record‑breaking year‑end bonuses, then shifts to a detailed explanation of LeetCode problem 953, describing how to determine whether a list of words is sorted according to a custom alien alphabet using both full‑array sorting and an optimized pairwise comparison approach, complete with Java code.
This article introduces a generic asynchronous processing SDK for Java back‑ends, explaining its design principles, advantages, component architecture, database schema, configuration via Apollo, usage steps, and practical demonstrations, while providing complete code snippets and a GitHub repository for reference.
This article introduces a lightweight IntelliJ IDEA plugin that automates the creation of Maven multi‑module projects, detailing its core features, installation methods, step‑by‑step usage, customization options, dependency handling, troubleshooting tips, and how to build and extend the plugin from source.
This article walks through a real‑world data‑migration case where 100,000 rows were moved from an old system to a new one, showing how naive per‑row inserts took five minutes and how a series of optimizations—batch SQL, JDBC batch mode, and multithreaded parallelism—reduced the runtime to just three seconds, while also covering common pitfalls and the final high‑performance implementation.
Spring Boot 4 restructures the framework into independent auto‑configuration modules, reducing package bloat, speeding up startup, lowering memory usage, and providing more precise and flexible configuration options for developers migrating from earlier versions.
The article explores the common dilemma of choosing between Long and BigDecimal for monetary values, summarizing ten distinct community suggestions ranging from using Long, BigDecimal, String, Protobuf, custom types, leadership advice, AI assistance, to minimalist integer approaches.
The author builds a lightweight Spring Pets test suite, evaluates three AI‑assisted migration strategies—contextual, incremental and hybrid—using OpenAI GPT‑4o, reports conversion coverage, performance, cost and practical challenges, and shares open‑source tooling for future Java framework migrations.
The article demonstrates how to achieve a ten‑fold reduction in API response time by building a three‑level cache pyramid (Caffeine L1, Redis L2, DB L3) in Spring Boot 3, covering dependencies, configuration, core template code, warm‑up, monitoring, load‑test results and common high‑concurrency pitfalls.
This article introduces the Reflector library—a comprehensive Java reflection utility—covers its core features, shows how to download it from GitHub, and provides step‑by‑step code examples for accessing private fields, invoking methods, creating instances, handling annotations, copying objects, and more, all with expected output.
This guide walks you through the purpose, core capabilities, environment setup, deployment options, channel configuration, template creation, API usage, troubleshooting, and architectural benefits of the Java‑based Austin unified message push platform for enterprise systems.
This article walks through designing a flexible login module that supports password, WeChat, and SMS authentication by applying the Strategy and Factory patterns in a Spring Boot project, showing code examples, project structure, and best‑practice tips for clean, maintainable backend development.
This article introduces a powerful, extensible Spring validation component built on SpEL that handles simple annotations, enum checks, multi‑field logic, and Spring Bean integration, providing step‑by‑step setup, usage examples, custom constraints, and performance considerations for Java backend developers.
json-io, a decade‑old Java JSON library known for zero‑config, circular‑reference support, and lightweight size, has added full TOON (Token‑Oriented Object Notation) read/write capabilities, a token‑efficient format designed for LLMs that can cut serialization costs by 30‑60% and integrates seamlessly with Spring Boot and Spring AI.
This article explains the motivation behind Java generics, their benefits such as compile‑time type checking and reduced casting, and provides concrete examples including generic classes, interfaces, collections, inheritance, custom generic methods, and common pitfalls, illustrated with code snippets and diagrams.
This guide reviews essential IntelliJ IDEA plugins for Java/Spring developers, covering their core features, installation steps, configuration tips, performance trade‑offs, and visual enhancements, helping you streamline workflow, reduce boilerplate, and improve code navigation in 2025.
This article explains the LeetCode 1297 problem of finding the substring that appears most often while respecting limits on distinct characters and length, and provides a detailed sliding‑window analysis together with complete Java and C++ reference implementations.
RabbitMQ supports transactional messaging to guarantee atomic delivery, using txSelect to start, txCommit to finalize, and txRollback to abort; this article explains the mechanism, outlines its advantages and performance drawbacks, and provides a complete Java example with step‑by‑step code walkthrough.
The article explains that big‑tech firms ask deep, “onion‑layer” questions to gauge a candidate’s potential and thinking ability, while smaller companies focus on detailed, practical queries to confirm immediate competence, and mismatches between these expectations often cause interview silence.
This article provides a comprehensive guide to gray releases and A/B testing, covering common scenarios, implementation methods, layered experiment design, hash-based bucket allocation, data collection workflows, statistical analysis, and practical Java and SQL code examples for reliable feature validation.
This article recounts Ron Garrett’s unlikely journey from NASA’s JPL to Google, his weekly plane commute, the chaotic development of the first AdWords system using Java and JSP, the billing bugs he faced, and how his work became the foundation of Google’s multibillion‑dollar advertising empire.
The article analyzes why interviewers at large tech firms ask increasingly detailed questions that may end without feedback, contrasts this with small‑company interview tactics, explains the mismatch, and offers concrete strategies for Java developers to handle such “soul‑crushing” queries effectively.
This article explains the principles of Java virtual threads, compares them with traditional platform threads, details RedJDK21’s implementation and performance improvements—including up to 31‑fold latency reduction and 24% CPU savings—in large‑scale services at XiaoHongShu, and discusses migration challenges, lock handling, monitoring, and future roadmap.
The article examines a production OutOfMemoryError caused by MyBatis SQL construction, explains heap and metaspace exhaustion, analyzes MyBatis source code, reproduces the issue with JVM settings, and offers practical recommendations to prevent similar memory failures.
The article walks through three concrete optimizations—batch SQL, JDBC batch mode with rewriteBatchedStatements, and multithreaded parallel inserts—that shrink a 100,000‑row MyBatis insertion from five minutes to three seconds, while highlighting configuration details, performance gains, and common pitfalls.
The article walks through turning a naïve MyBatis loop that took five minutes to insert 100,000 rows into a high‑performance solution that finishes in three seconds by applying batch SQL, JDBC batch mode with rewriteBatchedStatements, and multithreaded parallel execution, while highlighting pitfalls and best‑practice configurations.
The article analyzes three harmful forms of improper encapsulation—over‑encapsulation, fake encapsulation, and chaotic encapsulation—illustrates each with Java code examples, explains the resulting development inefficiencies, extensibility issues, and debugging difficulties, and offers concrete principles to avoid these pitfalls.
The article analyzes three common forms of bad encapsulation in Java—over‑encapsulation, false encapsulation, and chaotic encapsulation—illustrates their hidden risks with concrete code examples, and offers practical principles to restore clear responsibilities, minimal interfaces, and flexible design.
This article evaluates popular Java web frameworks by measuring performance, ecosystem maturity, learning curve, development efficiency, enterprise adoption and innovation, providing concrete data and practical recommendations for each framework’s strengths, use‑cases and drawbacks.
This article walks through converting a SpringBoot Maven project (mall‑tiny) to Gradle, explains Gradle’s key features and plugins, shows step‑by‑step setup, demonstrates dependency migration, compares build times with Maven, and provides a complete Gradle build script with reference links.
This guide walks a junior developer through why logging is essential, how to configure Logback in Spring Boot, use Lombok @Slf4j, choose appropriate log levels, apply parameterized messages, control output volume, enable asynchronous logging, manage log files with rolling policies, and integrate a centralized ELK stack for distributed systems.
When a Spring @Transactional method with REQUIRES_NEW fails to persist audit logs after a rollback, the issue often stems from misconfigured rollback rules, caught exceptions, self‑invocation, non‑public or final methods, or incorrect propagation settings, all of which prevent the new transaction from committing.
The article examines Maven 4’s major upgrades—including a new 4.1.0 POM model, Build POM/Consumer POM separation, explicit artifact types, subproject renaming, tree‑based lifecycle, and richer configuration expressions—while also noting the tool’s migration assistance and its impact on modern Java development.
Spring Boot packages all dependencies and an embedded web server into a single executable JAR, allowing developers to launch the application with a simple "java -jar" command without external configuration or server deployment.
This article explains how Java developers can retrieve a client’s IP address from an HttpServletRequest, handle proxy headers, and use the ip2region library (via Maven) to map the IP to its province and city, including code snippets and configuration details.
This article explains a custom OrderedTaskExecutor that uses hash‑based slot allocation and isolated queues to guarantee per‑business‑ID task ordering while preserving the high concurrency of a thread pool, illustrated with a call‑center use case and performance results.
When a Spring Boot application using @Scheduled is deployed on multiple servers, each instance triggers the same job, leading to duplicate processing; this article explains why the problem occurs, reviews simple single‑node and Redis lock approaches, and provides a step‑by‑step guide to integrate the ShedLock framework for reliable, annotation‑driven distributed locking.
This article combines a detailed Baidu 2026 campus recruitment salary table with an extensive Java interview guide covering collections, concurrency, thread creation, thread pools, I/O models, Spring bean lifecycle, Redis persistence, MySQL isolation levels, MVCC, storage engines, data structures, TCP/UDP differences, JVM memory layout, garbage collection algorithms, and a quicksort example, providing a comprehensive resource for backend developers preparing for technical interviews.
This article explains four practical ways to determine when tasks submitted to a Java ExecutorService have finished—using Future's isDone/get, ExecutorService.invokeAll, CompletionService, and CountDownLatch—each with code examples and usage guidance.
This article reveals ten hidden Spring Boot 3 configuration tricks—from disabling the whitelabel error page and shrinking Tomcat threads to enabling HTTP/2, tuning HikariCP, caching static assets, and leveraging Actuator metrics—each illustrated with code snippets and practical steps to boost application performance.
A recent production incident revealed duplicate order IDs caused by a flawed custom Snowflake algorithm; this article reviews the standard Snowflake structure, dissects the custom implementation’s critical mistakes—short timestamp, IP‑based business ID, zeroed worker and data‑center IDs—and offers best‑practice recommendations, including using mature libraries and proper worker‑ID strategies.
