The article examines how Java 21’s cheap virtual threads change the role of traditional thread pools, explaining why pooling virtual threads is a bad idea, how thread pools still act as natural throttlers, and which scenarios—especially CPU‑bound work and synchronized blocks—remain unsuitable for virtual threads.
In 2026, AI tools like Claude Code can generate all code, turning writing into a commodity, while the real value for Java developers shifts to domain judgment, architectural aesthetics, and AI collaboration skills that ensure code runs correctly, reliably, and sustainably.
The author recounts a 16‑year IT journey—from unproductive early jobs and frequent moves, through a pivotal switch to a major internet firm, to successive roles as tech lead, manager, and backend head—highlighting the challenges, decisions, and lessons that shaped a successful technical leadership path.
The article provides a side‑by‑side analysis of Spring AI 2.0 and LangChain4j, comparing their goals, version alignment, programming models, RAG and agent capabilities, ecosystem integration, learning curve, and operational considerations to help Java teams decide which library best fits their project constraints.
This article introduces Google Tink, an open‑source cryptographic library for Java, explains its design goals and primitive abstractions, and walks through concise code examples that generate keysets, perform AEAD encryption, stream large files, compute MACs, and create digital signatures, all with minimal boilerplate.
This article explains why the Model Context Protocol (MCP) is becoming the universal AI interface standard, compares three implementation approaches, and provides a step‑by‑step tutorial for Java developers to create a production‑ready MCP server with Spring Boot, including tool definition, registration, controller, LLM integration, and best‑practice optimizations.
This guide explains how to integrate Anthropic's Claude Code AI assistant into JetBrains IntelliJ IDEA, detailing a five‑minute setup, the deep IDE‑level fusion, project‑wide context awareness, immersive workflows, and a comparison with other AI coding solutions.
As AI accelerates Java business code generation, developers must carefully define transaction boundaries, distinguishing atomic operations, avoiding oversized or overly fragmented transactions, and coordinating with messaging and caching to ensure consistency, recoverability, and reliable system behavior.
This article walks through using RSA to encrypt Spring Boot API responses, covering the theory behind RSA, two security scenarios, Maven dependency setup, configuration, controller annotations, encryption/decryption code, a front‑end JavaScript example, common pitfalls, and a final security summary.
HashMap is not a simple key‑value store but an array‑based scheduling system that uses a three‑step put process, hash perturbation, bit‑wise indexing, and conditional conversion of long bucket lists into red‑black trees, with resize mechanics that can become performance bottlenecks in high‑concurrency Java applications.
This article explores the complete execution flow of Spring Boot’s auto‑configuration, detailing the role of @EnableAutoConfiguration, the AutoConfigurationImportSelector hierarchy, how candidate configurations are loaded from spring.factories, filtered by conditions, and how to create custom starters, with interview‑style Q&A.
This article walks through building a Spring Boot 3.5.0 service that uses Apache POI and XDocReport to load a DOCX file, extract images, convert it to HTML, and expose a controller endpoint for instant online preview without external plugins.
The article argues that Java developers should treat OpenAI's Codex as a coding agent capable of handling well‑defined engineering tasks—such as codebase navigation, targeted refactoring, test generation, and pre‑review checks—by clearly specifying boundaries, goals, and verification steps rather than merely asking it to write snippets.
This tutorial walks through building a Spring Boot 3 project that integrates Alibaba's EasyExcel for Excel export and import, covering project structure, Maven dependencies, entity mapping, listener implementation, service and controller code, testing endpoints, and key Spring Boot 3 considerations such as Jakarta packages, JDK 17+, response header handling, memory management, and production‑grade best practices.
This article walks through Spring Boot 3.5.0’s URI building tools—including UriComponents, UriBuilderFactory, encoding options, ServletUriComponentsBuilder, and MVC link generation—showing how to construct correct, automatically‑encoded URLs for RestTemplate, WebClient, and controller methods with concrete code examples and outputs.
The article introduces the liteflow rule‑engine framework, explains its architecture, component types, EL rule files, data‑context handling, configuration options, and demonstrates a real‑world e‑commerce workflow that replaces verbose if‑else code with concise rule definitions.
This article presents a detailed design of a Process Business Capability (PBC) architecture that decouples logistics workflow steps, replaces hard‑coded controller logic with configurable nodes, introduces a unified entry point, a flow engine for matching and execution, and demonstrates the complete Spring Boot implementation with code examples and database schemas.
The author announces a refreshed Spring AI 2.0 video tutorial series and provides a detailed overview of the framework’s design goals, provider‑agnostic API, full‑type model support, Spring integration, enterprise value, typical use cases, and a comparison with competing Java AI libraries.
The article explains Java’s reflection mechanism, showing how it lets code inspect and manipulate classes at runtime—enabling frameworks like Spring and MyBatis—while warning about performance overhead, security risks, and maintenance challenges, and offers best‑practice guidelines to use it safely.
This article dissects the @SpringBootApplication annotation, explaining how it combines @SpringBootConfiguration, @EnableAutoConfiguration, and @ComponentScan, and walks through the auto‑configuration mechanism, conditional annotations, and common interview questions with concrete code examples.
This guide demonstrates how to use a custom @SensitiveFilter annotation together with an AOP aspect and the lightweight sensitive‑word library to implement global sensitive‑word filtering in Spring Boot 3, supporting both automatic replacement and detection modes while eliminating repetitive code across controllers.
This article explains how ThreadLocal provides per‑thread variable copies in Java web applications, details its internal storage in Thread objects, showcases ten practical scenarios—from request tracing to async tasks—and highlights common pitfalls such as memory leaks and thread‑pool data contamination, offering concrete best‑practice recommendations.
This article dissects a comprehensive set of Barclays Java Spring Boot microservices interview questions, covering HashMap internals, REST method semantics, code implementations, Spring dependency injection, JDBC evolution, JPA/Hibernate usage, SQL injection defenses, microservice architecture essentials, and best‑practice REST API design.
In just 20 minutes, the author uses Cursor AI with Opus 4.7 to create a complete pet‑adoption solution that includes a WeChat mini‑program front‑end, a Vue‑based admin portal, and a Spring Boot backend with JWT security, demonstrating rapid AI‑assisted development and detailed architecture.
This article explains the core differences of Java's three I/O models—BIO, NIO, and AIO—through analogies, code examples, and a benchmark of 1,000 concurrent connections, then provides practical guidance on selecting the right model for various workloads.
Three high‑severity CVEs affecting Apache OpenNLP (up to version 2.5.8 and 3.0.0‑M2) enable denial‑of‑service, privilege escalation, and XXE attacks, allowing attackers to crash services, gain higher privileges, or read arbitrary files, and the article outlines mitigation steps.
This article dissects the Spring Boot startup sequence step by step, showing how a minimal @SpringBootApplication triggers listeners, type deduction, auto‑configuration loading, environment preparation, IOC container creation, bean refresh, and embedded Tomcat launch, with interview‑ready explanations.
The article explains how excessive if‑else branching in multi‑business Java systems harms maintainability and reliability, and demonstrates how a flow engine combined with plugin extensions can isolate code, configure per‑business execution chains, and safely handle success, rollback, and callbacks.
This article explains the fundamentals of Java annotations, their core purposes, built‑in annotations, meta‑annotations, and provides step‑by‑step practical examples for creating a runtime @Sensitive annotation and a compile‑time @AutoGetter processor, while also dissecting how Spring leverages annotations for component scanning, dependency injection, and request mapping.
The article clarifies the distinct meanings of concurrency, parallelism and asynchrony, explains their underlying mechanisms with concrete Java examples, highlights common misconceptions, and offers practical guidance on when to apply each model in real‑world systems.
After reviewing more than a thousand pull requests, the author identifies seven recurring problems—unreadable code, hidden error handling, thread‑safety oversights, N+1 database queries, hard‑coded configuration, ignoring failure paths, and overly large PRs—and explains why they matter and how to avoid them.
This article enumerates ten frequent pitfalls when using MyBatis‑Plus—such as incorrect total counts in pagination, pagination interceptor misconfiguration, logical‑delete failures, auto‑fill issues, optimistic‑lock mismatches, null handling in query wrappers, poor batch‑insert performance, enum mapping errors, type‑handler problems, and overall pros and cons—providing concrete examples, root‑cause analysis, and practical solutions for each.
The article explains how standard Spring Boot controller‑level validation leaves service methods unchecked, and demonstrates using @Validated with MethodValidationPostProcessor, custom exception handling, and a MethodValidationExcludeFilter to apply, convert, and selectively disable validation across the application.
The article explains how Java generics, introduced in Java 5 to improve type safety and reduce code duplication, rely on type erasure for backward compatibility, detailing its implementation, advantages such as compatibility and performance, drawbacks like lack of primitive support and overload restrictions, and practical techniques to mitigate these issues.
The article explains how MCP adds an AI‑friendly protocol layer on top of traditional Java backend services, enabling models to call tools safely, and outlines the security, governance, and testing practices Java engineers need to adopt.
The article presents ten practical AI prompt templates that cover the full software development workflow—from requirement clarification and code generation to testing, refactoring, debugging, performance tuning, SQL optimization, documentation, design review, and cross‑language translation—helping developers get accurate, production‑ready results from AI.
This article explores Java exception handling from basic try‑catch‑finally syntax, through multi‑catch and try‑with‑resources, to designing custom business exceptions, offering concrete code examples, logging tips, global handlers, and performance considerations for robust backend development.
This article walks through Spring Data JPA interface projections—from basic setup and field aliasing to association queries, closed vs. open projections, pagination, and dynamic use—showing how they eliminate redundant data fetching, improve performance, and avoid common pitfalls.
The article outlines a step‑by‑step learning system compiled by senior architects, covering skill foundations, source‑code analysis, distributed and microservice architectures, concurrency, performance tuning, essential Java tools, and a hands‑on e‑commerce project to help developers become well‑rounded architects.
This article explains the seven key differences between Java's primitive int and its wrapper Integer, covering default values, memory layout, comparison pitfalls, caching, autoboxing/unboxing, performance impact, and appropriate usage scenarios with concrete code examples and benchmarks.
The article explains how JDK 24’s Gatherer API extends Java streams with custom intermediate operations, compares its functionality to Groovy’s rich collection methods, and provides concrete Gatherer implementations for slicing, fixed and sliding windows, folding, and subsequence detection, complete with runnable code examples.
A tiny UI tweak that required a meeting with four backend groups exposed the pain of calling many micro‑services from the front‑end, and the article shows how introducing a Backend‑For‑Frontend (BFF) layer can aggregate, transform, and simplify those calls while improving reliability and performance.
The article analyzes how OpenAI's Codex CLI, an AI coding agent, is shifting Java development from manual code writing to task‑oriented automation, outlining suitable use cases, practical prompting techniques, and the new skills engineers must adopt to keep quality and control.
This article thoroughly examines Java's String, StringBuffer, and StringBuilder, explaining their internal implementations, immutability, JDK 9 changes, performance characteristics, and best‑practice usage scenarios, while providing concrete code examples, benchmarks, and interview questions to help developers choose the right tool.
The article explains that a daemon (background) thread in Java supports user threads but does not prevent JVM shutdown; when all non‑daemon threads finish, the JVM exits regardless of daemon threads, covering definitions, usage scenarios, creation methods, pitfalls, detailed comparisons, and typical interview questions.
This article explains why storing passwords and API keys in plain‑text configuration files is risky, outlines the three core principles of configuration security, and provides a step‑by‑step guide to using the @SecretValue annotation from the spring‑secret‑starter library to inject secrets safely from services such as AWS Secrets Manager.
The article explains how integrating Arthas with the Model Context Protocol (MCP) enables AI-driven, natural‑language troubleshooting of Java‑based online incidents, offering step‑by‑step diagnostics, concrete case studies, and a balanced view of its advantages and current limitations.
JDK 26 adds HttpRequest.BodyPublishers.ofFileChannel, letting developers read specific file segments directly from a shared FileChannel without copying data into heap memory, dramatically reducing memory usage and simplifying parallel chunk uploads to object storage such as OSS or S3.
This article walks through the design and implementation of a TCP long‑connection communication scheme using Netty and Spring Boot 2.2.0, covering project architecture, module layout, message flow, detailed code explanations, testing procedures, and deployment considerations.
This article explains how == compares primitive values and object references, why Object.equals() defaults to ==, how classes like String and Integer override equals(), the impact of the string constant pool, integer caching, auto‑boxing, floating‑point pitfalls, and best practices for correctly comparing objects in Java.
This article introduces MongoDB fundamentals, walks through Windows installation, shows how to integrate Spring Boot with MongoDB via Maven, configures connection settings, demonstrates both MongoRepository and MongoTemplate usage with full code examples, and compares MongoDB to Redis for typical use cases.
This article curates ten open‑source AI projects on Gitee that Java developers can use to learn RAG pipelines, AI agents, knowledge‑base construction, Text‑to‑SQL, workflow orchestration, and multi‑model integration, offering concrete use cases, learning goals, and guidance on selecting a learning path.
The article explains the four ways to create a thread pool in Java, why the Executors factory methods are unsafe for production, how to manually configure ThreadPoolExecutor with its seven parameters, and compares scheduled and ForkJoin pools while providing interview‑focused Q&A and practical configuration formulas.
This article analyzes ten frequent pitfalls when using MyBatis-Plus—such as incorrect pagination totals, pagination plugin misconfiguration, logical delete failures, auto‑fill issues, optimistic‑lock mismatches, null handling in QueryWrapper, batch‑insert performance, enum mapping errors, wrapper condition overrides, and type‑handler problems—provides root‑cause explanations, concrete code examples, and practical solutions to help developers write more robust and efficient Java backend code.
This guide shows how to integrate asyncTool into a Spring Boot project, configure custom thread pools, define core interfaces, and compose serial, parallel, or mixed task flows with full‑link callbacks, fault tolerance, and performance optimizations for complex multi‑threaded orchestration.
This article walks through building a Netty‑based WebSocket server integrated with Spring Boot, configuring the channel pipeline, implementing custom handlers, exposing a push‑message service, and testing the end‑to‑end flow that enables the backend to push real‑time messages to web clients.
The article explains why well‑crafted prompts are crucial for AI‑assisted programming, introduces the STAR principle for prompt design, and provides ten ready‑to‑use prompt templates covering requirement analysis, test generation, code explanation, refactoring, debugging, performance tuning, SQL design, documentation, architecture review, and language translation.
This article explains why CompletableFuture replaces traditional Future in high‑concurrency Java applications, demonstrates core APIs such as runAsync, supplyAsync, thenApply, allOf, anyOf, thenCombine, and exception handling, and provides detailed code examples—including serial, parallel, aggregation, and an e‑commerce order‑processing case—to guide robust asynchronous programming.
This article explains a standard Spring MVC + OpenFeign design pattern for microservices, where a contract‑first interface defines routing and API specs, Controllers implement business logic, and Feign clients reuse the same interface for remote calls, with full Maven project setup, code samples, and Nacos integration.
This article outlines a step‑by‑step Java learning roadmap—from core fundamentals to microservices, high‑concurrency, AI integration, and cloud‑native deployment—showing how targeted skill progression can dramatically boost both technical competence and earning potential.
This article demonstrates a step‑by‑step implementation of API anti‑brush (rate limiting) using a Spring Interceptor combined with Redis, explains how to configure time windows and request limits, introduces a custom @AccessLimit annotation for fine‑grained control, discusses path‑parameter pitfalls, real‑IP handling, and shares practical testing results.
The article demonstrates how to eliminate repetitive try‑catch blocks in Java Spring applications by using Spring's @ControllerAdvice for centralized exception handling, a custom Assert interface backed by enums for error codes, and unified response objects, resulting in cleaner, more maintainable code.
This article explains why Disruptor—a lock‑free, high‑throughput Java queue from LMAX—was chosen over traditional brokers, details its core concepts such as RingBuffer, Sequence, and WaitStrategy, and provides a step‑by‑step SpringBoot demo that can handle up to six million orders per second without pressure.
The article shows how a growing list of if‑else checks for user eligibility becomes hard to maintain, then walks through designing and implementing a Java rule engine—defining rule abstractions, building an AND/OR executor, and demonstrating usage with concrete examples, while discussing its advantages and drawbacks.
A tiny front‑end tweak that required five microservice calls turned the front‑end into a glue layer, prompting a meeting with four backend teams, and the author explains how adopting a Backend‑for‑Frontend (BFF) pattern resolves such integration pain points with concrete examples and code.
This article examines ten frequent pitfalls when using MyBatis-Plus—such as incorrect pagination counts, disabled pagination, logical‑delete mishandling, auto‑fill failures, optimistic‑lock issues, batch‑insert slowness, enum mapping errors, JSON type‑handler problems, and query‑wrapper quirks—explains their causes, and provides concrete code‑level solutions and best‑practice recommendations.
Starting from a simple sequential Java price‑aggregator, the article walks through successive architectural upgrades—concurrent calls with CompletableFuture, timeout and fallback handling, Spring Boot service exposure, caching, bulkhead isolation, microservice split, and Kafka‑driven event processing—showing how latency drops from 1500 ms to under 20 ms.
This article explains three Spring Boot 3.5.0 techniques—ResponseBodyEmitter, SseEmitter, and StreamingResponseBody—for delivering multiple asynchronous values as a stream, complete with code samples, curl demonstrations, and a front‑end EventSource example.
This article walks Java engineers through building production‑grade enterprise AI assistants, explaining the roles of LLM, RAG, Agent and Skill, detailing a layered architecture, best‑practice code samples, deployment strategies, observability, security and cost‑control considerations.
The article explains that recent Spring AI updates—AutoMemoryTools and the Session API—introduce long‑term and short‑term memory capabilities, arguing that Java AI agents must shift focus from merely invoking tools to managing context and memory to become reliable production systems.
MateClaw is an open‑source, Java‑centric AI operating system built on Spring Boot 3.5 and Spring AI Alibaba that runs as a single JAR, offering multi‑agent collaboration, a structured wiki‑style knowledge base, tool‑guarded utilities, multi‑model routing, and cross‑channel deployment while keeping all data on‑premises.
This article walks through Kafka’s core architecture, explains why it achieves massive throughput, and provides a step‑by‑step SpringBoot integration—including environment setup, Maven dependencies, configuration, producer and consumer code, advanced features like transactions and dead‑letter queues, plus performance monitoring and tuning tips.
The article enumerates ten typical traps when using MyBatis-Plus—such as incorrect pagination counts, ineffective pagination plugins, logical delete mishandling, auto‑fill failures, optimistic‑lock issues, null‑value conditions, batch‑insert slowness, enum mapping errors, wrapper overwrites, and type‑handler problems—explains why they occur, and provides concrete code‑level solutions and best‑practice recommendations.
This guide walks through setting up a local LLM with Ollama, configuring Spring Boot and LangChain4j, defining function‑calling tools for weather, order status, logistics and coupons, creating AI service beans, exposing REST controllers, and troubleshooting common integration issues.
This article analyzes the Model Context Protocol (MCP), detailing its architecture, JSON‑RPC extensions, Streamable HTTP transport, and governance layers, and demonstrates how to transform high‑traffic Java microservices into a secure, observable AI‑native capability layer using an independent MCP gateway, tooling standards, and production‑grade implementations.
The article explains why returning a Result wrapper from the Service layer couples business and presentation logic, reduces reusability, complicates testing and transaction handling, and suggests keeping services pure by returning domain objects and handling errors via exceptions.
Sun Microsystems, once hailed for its groundbreaking CPUs, operating systems, and programming language, rose from a Stanford‑born workstation startup to dominate 80s‑90s workstations and servers, but arrogance, market blind spots, and the rise of Linux and Intel CPUs led to its rapid decline and eventual acquisition by Oracle.
This article explains why Java generics are essential, clarifies the conventional meanings of type parameters T, E, K, V, describes how to use unbounded, upper‑bounded and lower‑bounded wildcards, introduces the PECS rule, details type erasure, and lists common pitfalls with practical code examples.
This article explains why RabbitMQ is essential for distributed systems, outlines its core functions and typical scenarios, and provides step‑by‑step instructions for setting up Docker or local installations, adding Maven dependencies, configuring SpringBoot, and implementing Direct, Fanout, and Topic exchange patterns with code examples and troubleshooting tips.
This article explains Java object type conversion, covering upcasting (implicit parent‑to‑child casting) and downcasting (explicit child‑to‑parent casting), their safety rules, static method behavior, and how to use the instanceof operator to avoid runtime errors.
This guide walks through using the SpringAIAlibaba framework to integrate Alibaba Baichuan with Spring Boot via LangChain4j, explains core concepts, compares LangChain4j to Spring AI and OpenAI, and provides step‑by‑step dependency setup, environment configuration, code examples, and a simple browser test.
This guide demonstrates how to integrate LangChain4j into a SpringBoot application to enable multi‑turn chat memory and per‑user session isolation using @MemoryId, configuring ChatMemoryProvider, updating the AI service interface, and testing with curl requests.
This article explains why traditional function‑calling is insufficient for production AI services and shows how Spring AI's Model Context Protocol (MCP) introduces bidirectional communication, addressable resources, parameterized prompts, tool orchestration, and server‑initiated sampling, providing a complete roadmap to build a production‑grade AI microservice architecture.
This article walks through building a complete OAuth2.0 solution in Spring Boot, covering core concepts, a comparison of the four grant types, project initialization, detailed configuration of the authorization and resource servers, custom login pages, end‑to‑end testing, advanced optimizations, and security best‑practice recommendations.
MyBatis generates mapper implementations at runtime using JDK dynamic proxies; the proxy intercepts interface calls, builds a statementId from the interface’s fully‑qualified name and method name, looks up the corresponding MappedStatement via the namespace‑id convention, and delegates execution to SqlSession, eliminating the need for a concrete class.
The article explains why loading a Java AI agent with dozens of tools hurts token efficiency and accuracy, and how Spring AI’s dynamic tool discovery—implemented via ToolSearchToolCallAdvisor—lets models fetch only the needed tools per turn, saving up to 64% of tokens and simplifying tool governance for large Java back‑ends.
The article dissects an Alibaba interview question about the volatile modifier, showing why answering only with a lazy‑loaded singleton is insufficient, and explains how volatile prevents instruction reordering, establishes memory barriers, and creates happens‑before relationships to make double‑checked locking safe.
This article demonstrates seven practical ways to access configuration properties in a Spring Boot 3.5.0 application, covering ContextRefreshedEvent listeners, ConfigurableEnvironment, the Environment interface, @Value, @ConfigurationProperties, ConfigurableBeanFactory, and the Actuator /env endpoint, each with code examples and usage notes.
This guide explains why plain HTTP is unsafe for enterprise projects, outlines the core principles and benefits of HTTPS and HTTP/2, compares certificate types, provides step‑by‑step commands to generate self‑signed and authority‑issued certificates, and shows how to configure SpringBoot, enable automatic HTTP‑to‑HTTPS redirects, verify HTTP/2 activation, and apply production‑grade security hardening.
The 2025 MCP specification replaces the old HTTP+SSE transport with Streamable HTTP, requiring Java services to handle both POST and GET, manage session IDs, support reconnection and authentication, and rethink gateway, load‑balancing, and client recovery strategies instead of relying on a simple SSE long‑connection model.
The article explains why ordinary MyBatisPlus pagination becomes slow and memory‑hungry when processing millions of rows, and demonstrates three alternatives—regular query, stream query, and cursor query—detailing their implementations, trade‑offs, and practical code snippets for MySQL and Oracle environments.
This article explains how to protect user privacy in SpringBoot applications by masking sensitive fields such as phone numbers, ID cards, emails, bank cards, names, and addresses during JSON serialization using a custom Jackson serializer and annotation, offering a zero‑intrusion, high‑performance solution compared to other approaches.
An interview‑focused analysis explains how processes allocate resources, threads handle CPU scheduling, and coroutines act as lightweight user‑mode threads, comparing their creation costs, switching overhead, and memory usage, and highlights Java 19/21 virtual threads as the Java implementation of coroutines.
This guide shows how to set up a Spring Boot 3.x project with JDK 17, add the spring‑ai‑alibaba‑starter, configure an Alibaba Cloud Bailei API key, and implement a simple chat controller to call the model via Spring AI.
Easy‑Trans is a SpringBoot starter that provides five translation modes—simple ID‑to‑name, dictionary code‑to‑text, enum mapping, RPC cross‑service, and custom data source—allowing developers to replace repetitive lookup code with a single @Trans annotation, optionally enabled with caching for high performance.
This article compares Spring AI 2.0 and LangChain4j, examining their positioning, version alignment, architecture, programming model, RAG support, observability, learning curve, and ecosystem integration to help Java teams decide which library best fits their AI project constraints.
The article presents a step‑by‑step, three‑month‑tested workflow that embeds Anthropic Claude and OpenAI Codex into IntelliJ IDEA via the Continue plugin, enabling Java developers to auto‑generate CRUD code, unit tests, and refactorings, connect Claude to the database, and avoid repetitive coding tasks without purchasing a subscription.
This note explains Java inheritance, covering the single‑inheritance class hierarchy, a Car class example, a ChildCar subclass that adds a load field, and eight key inheritance capabilities such as member reuse, method overriding, and constructor chaining, illustrating why inheritance improves code reuse and quality.
This article demonstrates how to create a millisecond‑level real‑time online user tracking system using Spring Boot 3.5, WebSocket with STOMP, and Redis pub/sub, covering environment setup, Maven dependencies, server‑side configuration, presence services, event listeners, and a simple front‑end page.
The article examines the delayed double‑delete cache invalidation technique, reveals its hidden risk of cache‑penetration‑induced database load, compares Facebook's lease‑based solution and Uber's version‑number approach, and advises when the method is appropriate for high‑traffic systems.
