This article explains how to secure OpenAPI interfaces by using globally unique AppId/AppSecret pairs, SHA‑256 and RSA signatures, timestamp and nonce validation, caching, rate‑limiting, parameter validation, and encryption algorithms, providing complete client‑server implementation examples in Java.
This article demonstrates how to insert 300,000 rows into a MySQL table using MyBatis and JDBC, compares direct batch insertion, row‑by‑row insertion, and optimized batch strategies, and provides performance measurements and practical tips for efficient large‑scale data loading.
This article explains how to use IntelliJ IDEA's advanced debugging features, including conditional breakpoints and the evaluate expression tool, with step‑by‑step instructions, practical code examples, and tips for efficiently locating and fixing Java runtime errors.
James Gosling, the Canadian creator of Java, announced his retirement after a five‑decade career that spanned IBM, Sun, Oracle, Google, Liquid Robotics and Amazon, highlighted by pioneering the Java language and virtual machine, earning prestigious awards and widespread admiration from the developer community.
This article compares popular Java etcd client libraries, evaluates their features, performance, and suitability, and provides a hands‑on tutorial using jetcd with Maven dependencies, code examples for watching and reading keys, and discusses runtime considerations such as thread handling.
This article walks through the sixteen JDK 14 JEPs, focusing on JEP 305’s instanceof pattern matching, JEP 361’s switch expressions, and JEP 368’s text blocks, providing design motivations, code comparisons, step‑by‑step usage, and practical tips for modern Java development.
The article explains why a NullPointerException occurs when a null String is used in a switch statement, detailing the underlying equals() and hashCode() calls, the required preconditions, and how Java compiles String switches, supplemented with illustrative code examples.
This article explains the drawbacks of using Spring Boot's @Value for configuration injection, demonstrates how @ConfigurationProperties provides a cleaner, maintainable alternative, and shows how to add validation with @Validated and standard bean validation annotations.
The guide demonstrates how to build a front‑end/back‑end separated captcha login using Spring Boot, Kaptcha and Redis, showing Redis‑based captcha storage with a unique key, Base64 image delivery, and verification logic that replaces traditional session‑based approaches.
This article demonstrates how to use the Template Method, Factory Method, and Strategy patterns in a Java Spring e‑commerce fulfillment system to clearly separate channel‑specific order handling, improve code maintainability, and enable rapid addition of new order types.
PowerJob is a Java‑based, enterprise‑grade distributed task scheduling platform offering a web UI, multiple scheduling strategies (CRON, fixed rate, delay, API), diverse execution modes, workflow support, and high‑availability, with detailed installation steps via Docker or JAR, configuration guidance, and sample code.
The article explains the concept of a dynamic thread pool, identifies common pain points such as invisible runtime status, hard‑to‑trace rejections, and slow parameter tuning, and presents a comprehensive solution that includes monitoring, alerting, automatic stack dumping, and live parameter refresh for Java backend services.
This article explains the evolution from traditional cookie‑session authentication to token‑based JWT, detailing its structure, security mechanisms, implementation steps, advantages, limitations, and practical Java code examples, while also comparing it with modern authentication challenges in web and mobile environments.
This article explains how to standardize API responses in a micro‑service architecture by defining a JSON result format with code, message, and data fields, using HTTP‑like status code ranges, and automatically wrapping controller outputs with a custom @ResponseResult annotation and Spring's ResponseBodyAdvice.
The June 2024 VS Code for Java update introduces enhanced project settings with new compiler, Maven, and formatter tabs, easier access via the status bar, test coverage improvements, Gradle Build Server projects, Spring feature upgrades including @DependsOn support and Spring Boot 3.3 compatibility, and new extension packs for Java development.
This guide explains how to implement data permission control in MyBatis-Plus by creating a custom annotation, an interceptor that modifies SQL before execution, a handler that builds WHERE clauses based on user roles, and how to register the interceptor in the MyBatis-Plus plugin, covering both basic and advanced versions.
This article introduces the Java Topology Suite (JTS), explains its core geometry models, WKT format, spatial relations, and operations, and demonstrates how to efficiently determine whether a point lies within service coverage polygons using MBR filtering, spatial indexes such as R‑tree and Quadtree, and geometry repair techniques.
James Gosling, the creator of Java, has announced his retirement, prompting a look back at his life, the birth of Java from the Green project, its evolution, and his post‑Sun career moves through Oracle, Google, a robotics startup, and finally AWS.
This article describes a backend solution for a company approval workflow that extracts key information from company names, tokenizes them using IKAnalyzer, applies MySQL REGEXP for fuzzy matching, and sorts results by match degree, complete with code examples and deployment tips.
This article explains the five SOLID design principles—SRP, OCP, LSP, ISP, and DIP—detailing their definitions, common violations, and Java code examples that demonstrate how to refactor classes for better modularity, extensibility, and maintainability.
The article explains AutoMQ's memory‑cache architecture, compares LogCache and BlockCache designs, analyzes Netty's internal and external memory fragmentation caused by the Buddy and PageRun/PoolSubpage allocators, and presents mitigation techniques such as ByteBufSeqAlloc to reduce OOM risks.
This article introduces Lock4j, a versatile Java distributed‑lock component supporting RedisTemplate, Redisson and Zookeeper, explains its key features, shows how to add dependencies and configure Redis, details the @Lock4j annotation attributes, provides simple and advanced usage examples with code snippets, and demonstrates custom executors, key builders, failure strategies, and manual lock handling.
This article demonstrates how to leverage Spring's TransactionSynchronizationManager to detect active transactions and register synchronization callbacks that asynchronously push payment‑ledger messages to Kafka only after the transaction successfully commits, ensuring data consistency and minimal impact on the main business flow.
This article walks through the complete troubleshooting process for a non‑functional logback‑spring.xml in a Spring Boot application, covering background, configuration steps, common pitfalls such as variable resolution and dependency conflicts, remote debugging techniques, and final recommendations to ensure proper log output.
This comprehensive guide walks you through Shiro's core concepts, authentication and authorization mechanisms, various realm implementations, session management, distributed session handling with Redis, caching strategies, and step‑by‑step integration of CAS single sign‑on using SpringBoot and pac4j, complete with code samples.
This article presents a real‑world case of optimizing a high‑concurrency transaction‑statistics API, detailing diagnosis of a 30‑second latency, SQL refactoring with array_agg and unnest, Java‑level improvements, and Caffeine caching, while also sharing promotional offers for ChatGPT services and a developer community.
This guide explains how to enable detailed G1 GC logging in Java, interprets both Minor (YGC) and Full GC log entries, breaks down heap size changes, worker threads, pause times, and points to the GCEasy analysis tool for deeper insight.
This article explains the fundamentals of symmetric and asymmetric encryption, how digital signatures and HTTPS work with certificate authorities, and demonstrates a practical implementation of secure URL encryption, key exchange, and request validation using custom Spring Cloud Gateway filters written in Java.
This article explains how to implement distributed locks using Redis, starting with a simple SETNX approach, identifying its shortcomings, and then presenting solutions such as thread‑identifiers, Lua scripts for atomicity, handling TTL with watchdogs, the RedLock algorithm, and practical usage via the Redisson Java client.
This article provides a step‑by‑step guide for Java engineers on building a Retrieval‑Augmented Generation (RAG) application using the LangChain4j framework, covering RAG fundamentals, environment setup, Maven integration, document loading, splitting, embedding with OpenAI, vector store management with Chroma, and prompt‑based LLM interaction.
This article explains how to implement distributed locks using Redis, starting with a basic SETNX approach, identifying its shortcomings, and then presenting robust solutions such as identifier‑based unlocking, Lua scripts for atomicity, the RedLock algorithm, and Redisson’s advanced features including a watchdog mechanism.
This article explains how to design a unified API response format for backend services, covering JSON structure, status code conventions, message handling, data payload, a Result wrapper class, controller simplifications, custom annotations, interceptors, and global exception handling to achieve clean and maintainable code.
This article explains how to replace Spring Boot's default embedded Tomcat with the high‑performance Undertow server, detailing Undertow's features, providing Maven dependency changes, showing configuration steps, and presenting benchmark results that compare QPS and memory usage, concluding that Undertow is preferable for high‑concurrency Java backend applications.
This article explains how to protect sensitive database credentials in SpringBoot applications by encrypting passwords in configuration files, leveraging Jasypt and a custom BeanFactoryPostProcessor to transparently decrypt values at runtime.
This article explains Java Metaspace and metadata GC thresholds, compares PermGen with Metaspace, and provides detailed JVM flag configurations—including size settings and compressed pointer options—to help developers optimize memory usage and garbage‑collection performance.
This article introduces Java 8 Stream API, explaining its declarative approach to processing collections, and demonstrates common operations such as filter, map, sorted, forEach, collect, statistics, and parallelStream with a PO class example, while also including full source code and brief promotional notes.
Learn how to enforce data permission rules in Java applications by using MyBatis mapper annotations, ThreadLocal context propagation, and custom MyBatis interceptors that modify SQL via Druid's AST parser, ensuring minimal intrusion to existing business logic.
This article explains the motivation behind creating the Easy-Query ORM for Java, demonstrates its fluent query capabilities—including single‑record, list, pagination, joins, sub‑queries, group‑by, native SQL and dynamic condition features—provides extensive code examples, and shares repository links for further exploration.
The latest TIOBE index shows Java falling out of the top three for the first time, C# overtaking it with a rapid market‑share gain, and Kotlin climbing back into the top twenty, while a detailed list of other languages and historical charts illustrate broader programming language trends.
This tutorial demonstrates how to set up a simple MySQL database, create a Spring Boot project, add Mybatis-Plus dependencies, install the MybatisX plugin, configure the connection, generate entity, mapper, service, and controller code, and verify the integration with a sample REST endpoint.
This article presents a comprehensive guide to improving Java backend performance by using parallel processing with CompletableFuture, minimizing transaction scope, applying effective caching strategies, configuring thread pools, reducing object creation, and employing various concurrency controls such as volatile, CAS, and read‑write locks.
This article explains why a Java thread pool with many waiting threads does not release resources, how calling shutdown or shutdownNow interrupts idle workers, how the ThreadPoolExecutor internals handle interruptions, and why proper shutdown is essential to allow both threads and the pool itself to be garbage‑collected.
This article explains the concept of request debouncing, outlines ideal debounce component characteristics, identifies which API endpoints need debouncing, and provides detailed Java implementations using shared Redis cache and Redisson distributed locks, including custom annotations, key generation, and practical testing results.
This article explains the TCP packet fragmentation and aggregation problems, introduces Netty's various decoder mechanisms such as FixedLengthFrameDecoder, LineBasedFrameDecoder, DelimiterBasedFrameDecoder, LengthFieldPrepender, and LengthFieldBasedFrameDecoder, and provides detailed configuration examples and code snippets for implementing robust TCP protocols.
This article demonstrates how to define a simple Calculator interface, provide both annotation‑based and reflection‑based implementations, and dynamically hot‑deploy user‑supplied JAR files by loading them with URLClassLoader, registering Spring beans, and handling bean removal on JAR deletion.
This article explains how to design a clean Controller layer in Spring Boot, introduces a unified response format with Result and ResponseBodyAdvice, demonstrates parameter validation using JSR‑303 and Spring Validation, and shows custom validation annotations and global exception handling to keep controller code concise and maintainable.
This article details a step‑by‑step investigation of a JSF thread‑pool exhaustion error that occurred when upgrading the Redis version of JD's internal R2M distributed cache, analyzing stack traces, lock contention, ForkJoinPool behavior, and the eventual remediation steps.
The Java Module System (Project Jigsaw) introduced in Java 9 defines uniquely named modules with descriptors that declare dependencies, exported and opened packages, and services, enabling clear dependency management, smaller custom runtimes, stronger encapsulation, improved performance, security, and easier maintenance, while supporting migration strategies and best‑practice guidelines.
This article explains the core architecture of Spring Security 6.x, detailing how a chain of servlet Filters implements authentication and authorization, the role of DelegatingFilterProxy, SecurityFilterChain, and the extensible components such as AuthenticationManager, UserDetailsService, and PasswordEncoder.
This article demonstrates how to insert 300,000 rows into a MySQL table efficiently by defining a User entity, configuring MyBatis and JDBC, comparing direct batch insertion, row‑by‑row insertion, and optimized batch strategies with configurable batch sizes and wait times, and provides performance results and best‑practice recommendations.
This article explains how to embed Lua scripts in Java applications with LuaJ, how to call Java code from Lua using LuaJava, and demonstrates dynamic extension, script auto‑upgrade, and bidirectional interaction through comprehensive code examples and detailed explanations.
This tutorial explains how to globally enforce data‑permission filtering in MyBatis‑Plus by creating a custom @UserDataPermission annotation, implementing an InnerInterceptor that modifies SQL WHERE clauses based on user roles, and configuring the interceptor within the MyBatis‑Plus plugin system.
The article explains the concept of dynamic thread pools, analyzes common pain points such as invisible runtime status, hard‑to‑locate rejections, and slow parameter tuning, and presents a comprehensive solution that includes monitoring, alerting, automatic stack tracing, and on‑the‑fly parameter refresh using Java code.
Learn how to use Maven Archetype to create standardized project skeletons, customize templates, generate and share archetypes, and integrate them into IDEs, streamlining Java project initialization, reducing manual setup errors, and improving development efficiency across teams.
This article walks through Java 17’s most useful language upgrades—including text blocks, enhanced NullPointerException messages, records, switch expressions, private interface methods, pattern matching, collection factories, Stream API extensions, the new HttpClient, JShell, direct file execution, and ZGC—showing why upgrading from Java 8 can boost code clarity and productivity.
This article explains why @Configuration classes can cause circular dependency and custom BeanPostProcessor issues in Spring Boot, and provides practical solutions such as enabling circular references, using static @Bean methods, and preferring constructor injection for reliable bean injection.
This article compiles 21 practical keyboard shortcuts for Java developers, ranging from redo and code template insertion to refactoring and navigation, while also noting a Windows 11 input‑method conflict and inviting readers to join a backend‑focused technical community.
This tutorial explains MinIO's features, common application scenarios, step‑by‑step CentOS 7 Docker installation, Spring Boot configuration, utility classes for bucket management, file upload/download, presigned URLs, and provides REST endpoints for handling large file uploads in Java backend applications.
A Java developer recounts how an unexpected Excel export failure was traced to mismatched EasyPOI and Apache POI versions, the impact of Maven's -U flag, and the step‑by‑step resolution involving dependency alignment and careful version selection.
This article explains why monitoring HTTP requests in Spring Boot is essential for stability, performance, debugging, user analysis, and security, and provides a complete hands‑on tutorial using Actuator to record, view, customize, and persist request‑response data.
This article demonstrates how to transform overly complex Spring Boot controllers—filled with repetitive try‑catch blocks and manual field checks—into clean, maintainable code by applying @Valid validation, reducing boilerplate, and implementing a centralized exception‑handling strategy.
This article walks through practical Java backend performance techniques—including parallel processing with CompletableFuture, fine‑tuned thread‑pool configuration, transaction scope minimization, cache‑line awareness, object‑pool usage, lock granularity, copy‑on‑write collections, and network payload reduction—backed by concrete code samples, benchmark results, and step‑by‑step analysis of trade‑offs and best practices.
This article details how a large restaurant chain leveraged the open‑source Sentinel framework to implement comprehensive traffic protection, rate limiting, and circuit‑breaking across millions of daily orders, describing challenges, design choices, high‑availability rule distribution, monitoring, user‑experience considerations, and providing Java code examples for integration.
This article provides a step‑by‑step tutorial for installing and configuring the CheckStyle plugin in IntelliJ IDEA, explains how to address common CheckStyle warnings such as missing annotations, spacing, naming, formatting, logical errors and import‑order issues, includes screenshots, and also contains promotional material for ChatGPT services and a community group.
This guide provides a comprehensive walkthrough of installing OpenCV, using its Java API for image and video face detection, implementing face comparison, creating custom GUI windows, and integrating the library into a Spring Boot application with detailed code examples and common troubleshooting tips.
This article explains how to create a custom annotation and a MyBatis-Plus interceptor that automatically adds data‑permission WHERE clauses based on the current user's role, covering both a basic implementation and an advanced version with role‑based scope handling.
This article explains what a service gateway is, why it is essential for microservice architectures, outlines its core functions and design considerations, and presents a practical Java‑based technology stack including Spring Boot, Netflix Zuul, Consul, JWT, Prometheus, and ELK.
This article demonstrates how to implement hot‑pluggable AOP in Spring by allowing users to dynamically add or remove advice at runtime, covering prerequisite concepts, core logic, complete code examples, and test scenarios that show logging activation and deactivation without restarting the application.
This article explains the concept of cache preheating, provides an abstract cache class, a Spring ApplicationContext utility, a CommandLineRunner handler to load hot data at startup, and demonstrates a concrete NewsCache implementation with Redis integration, followed by a REST endpoint to access the cached data.
This article demonstrates how to convert a list of Java objects into a Map using Stream's toMap collector, addresses duplicate key exceptions by providing a merge function, handles null values with Optional, and compares stream-based solutions with traditional for-loop approaches.
Learn how to efficiently import large Excel files into a database using POI, JDBC, MyBatis, and Spring Boot, with step-by-step code examples, performance bottlenecks, and optimization techniques such as caching, asynchronous processing, multi-threaded batch inserts, and thread‑pool configuration for maximum throughput.
This guide shows how to deploy Apache Flink 1.17 in Docker, configure off‑heap memory, connect it to Pulsar via the 4.1.0‑1.17 connector, run example jobs that copy topics and perform windowed word‑count, and provides Maven dependencies, custom serialization tips, batching settings, and version‑specific best‑practice notes.
This article explores eleven practical approaches for implementing delayed tasks in Java, covering native APIs like DelayQueue and Timer, thread‑pool executors, popular message‑queue solutions such as RocketMQ and RabbitMQ, as well as Redis‑based techniques, Redisson, Netty, Hutool, Quartz, and simple polling implementations.
This article explains why generic Java bean property copy utilities like Spring BeanUtils, Apache Commons BeanUtils, and CGLIB can cause runtime type conversion errors and performance issues, demonstrates the problems with code examples, and recommends using custom converters or IDE‑generated mapping code such as MapStruct for safe and efficient object transformation.
This article provides a comprehensive analysis of Spring Security 6.1, covering its core architecture, the role of FilterChainProxy, detailed authentication and authorization flows, key interfaces such as SecurityFilterChain, AuthenticationManager, and practical code examples to help developers understand and debug the framework.
This article explains the fundamentals of distributed tracing in microservice environments, introduces OpenTracing standards, details SkyWalking's architecture and sampling strategies, evaluates its performance against competitors, and shares practical company adaptations such as custom plugins, forced sampling, and trace ID logging.
The article reveals that MyBatis’s OGNL treats a single‑character literal like '1' as a Character, causing equality checks against String values in if tags to fail, and shows how using double quotes, toString(), or proper type conversion resolves the comparison pitfall.
This article provides a comprehensive introduction to common Java design patterns—including Strategy, Factory, Singleton, Proxy, Observer, Template Method, and Adapter—explaining their concepts, typical use‑cases, and complete code implementations with Spring Boot integration for practical application development.
This article analyzes a NullPointerException triggered by Lombok's @Accessors(chain=true) when using BeanCopier, explains how the altered setter return type prevents JDK Introspector from recognizing write methods, and provides two practical solutions to fix the issue.
This article demonstrates how to add jCasbin to a Spring Boot project, covering Maven dependencies, configuration files, Enforcer initialization, custom policy objects, a servlet filter for authorization, and dynamic add‑remove permission APIs, enabling lightweight, database‑driven access control.
retrofit-spring-boot-starter is a lightweight, type‑safe HTTP client framework for Spring Boot that integrates Retrofit with Spring, offering features such as custom OkHttpClient injection, annotation‑based interceptors, connection pool management, logging, retry, error decoding, circuit‑breaker support, and flexible configuration via YAML.
This article compares Spring Boot and Quarkus across architecture, startup speed, memory usage, and native image support, presents detailed JMeter performance tests, and offers practical guidance for migrating Spring applications to the cloud‑native Quarkus framework.
This article surveys the most suitable programming languages for artificial intelligence, examining Python, R, Java, LISP, Prolog, C++, Haskell, JavaScript, and Julia, and outlines their strengths, ecosystem support, and use cases to help developers choose the right tool for AI projects.
This article explains how to guarantee that when any asynchronous thread fails during a large Excel import, the main thread can roll back all related transactions, covering the limitations of @Transactional and @Async, thread‑local propagation, and practical solutions using Future, CompletableFuture, custom ForkJoinPool, and manual transaction management.
This article details the design and implementation of a Java SpringBoot seckill system, covering its architecture, technology stack, double‑MD5 password encryption, distributed session management with Redis, unified exception handling, page and object caching, static page generation, memory‑flag plus Redis pre‑decrement and RabbitMQ asynchronous order processing, oversell prevention, and API rate limiting, accompanied by key code snippets.
This article explains the purpose, constructors, common methods, formatting techniques, and exception handling of Java's BigDecimal class, providing code examples and best‑practice recommendations for performing high‑precision calculations in Java applications.
This article explains how to create a consistent JSON response format with status codes, messages, and data payloads, and how to automate its generation in Java Spring using a custom @ResponseResult annotation, interceptor, and controller advice to simplify backend development and improve front‑end integration.
This article provides a comprehensive technical overview of pfinder, JD's next‑generation APM system, covering its core concepts, feature set, comparison with other tracing tools, bytecode modification techniques using ASM, Javassist, ByteBuddy and ByteKit, Java agent injection via JVMTI and Instrumentation, plugin loading, trace‑ID propagation across threads, and a prototype hot‑deployment capability.
pfinder, JD’s in‑house APM system, provides full‑link monitoring, multi‑dimensional metrics, automatic instrumentation, topology mapping, trace analysis, AI‑driven fault detection by leveraging bytecode enhancement techniques such as ASM, Javassist, ByteBuddy and ByteKit, and integrates with JVM agents for hot‑deployment and trace propagation.
The article walks through a puzzling JSON deserialization failure in a Java filter using FastJSON, compares it with Gson and Jackson, discovers that hidden escape characters cause the error, and shows how unescaping the string resolves the issue.
This guide walks through creating custom FailureAnalyzers, registering EnvironmentPostProcessors, configuring non‑web applications, switching profiles for YAML settings, altering the embedded web server, and customizing server factories in Spring Boot 3.2.5, complete with code examples and screenshots.
This article explains the Fork/Join model and Java's ForkJoinPool, covering the divide‑and‑conquer algorithm, custom RecursiveTask examples, core source‑code analysis, common pool pitfalls, and performance testing to help developers decide when and how to use ForkJoinPool effectively.
This article provides a detailed tutorial on installing MinIO on CentOS 7 using Docker, configuring it, integrating with Spring Boot for multipart upload, generating presigned URLs, and includes complete Java code examples for utilities and controllers, covering use cases, deployment steps, and troubleshooting tips.
This article introduces the Java Caffeine caching library, explains its manual, loading, and async cache APIs, details eviction and refresh strategies, shows how to collect statistics, and demonstrates full integration with Spring Boot using Maven dependencies, cache annotations, constant definitions, configuration classes, and usage examples.
This article explains the principles, features, and workflow of Java's Z Garbage Collector, provides detailed configuration and logging guidance, and shares AutoMQ's practical tuning experiences that achieve sub‑millisecond pause times and improved performance for latency‑sensitive backend services.
This article explores MyBatis dynamic SQL, shares a real OOM incident caused by missing backend validation, and offers practical tips on parameter checking, balancing reusable and specialized interfaces, and adopting defensive programming to build more reliable Java backend services.
This article explains the limitations of ThreadPoolExecutor, introduces the Fork/Join model and ForkJoinPool, demonstrates how to implement divide‑and‑conquer tasks with RecursiveTask, provides performance benchmarks, and discusses design details, task submission methods, work‑stealing, and cautions about using the common pool.
This guide walks you through using Spring AI and Spring Cloud Alibaba AI to quickly create a Java chat application powered by Alibaba's Tongyi large‑model service, covering setup, configuration, core code, and verification steps for a functional generative AI chatbot.
MapStruct is a compile‑time Java bean‑mapping generator that, when added as an annotation processor in Maven, Gradle or an IDE, lets developers define @Mapper interfaces to automatically produce type‑safe, high‑performance implementations—including custom field mappings, nested collections, and lifecycle hooks—thereby eliminating boilerplate code and centralizing mapping logic.
This article explains how to use IntelliJ IDEA's diagram feature to view, clean up, and explore the inheritance and interface implementation relationships of Java Servlet classes, including tips for removing irrelevant nodes, inspecting class members, adjusting visibility, zooming, and adding related classes to the diagram.
