This article describes a lightweight, non‑intrusive MyBatis plugin that adds identifiable coloring comments to SQL statements—embedding statementId, pFinderId, and optional custom data—to simplify SQL source tracing, improve slow‑SQL analysis, and support SELECT, INSERT, UPDATE, DELETE operations with minimal performance overhead.
This article demonstrates how to wrap EasyExcel in a SpringBoot‑MyBatis‑Plus project, providing clear steps, code examples, and solutions to common issues such as date conversion and POI version compatibility, enabling developers to import and export Excel data with minimal effort.
This article explains how to replace Spring Boot's default embedded Tomcat with the Undertow container, details the configuration steps, and presents benchmark results showing Undertow's superior throughput and lower memory usage under high‑concurrency workloads, making it a better choice for performance‑critical applications.
This article explains how to efficiently handle massive Excel import and export tasks in Java by using EasyExcel, Java 8 functional programming, reflection, generics, thread‑pool batching, and custom ReadListener implementations, while also providing Maven dependencies and reusable export utilities.
This article explains how Spring Framework's ResponseBodyEmitter enables real‑time, chunked HTTP responses for use cases such as log streaming, progress updates, chat, and AI output, detailing its advantages over SSE, usage scenarios, core methods, a complete controller example, and best‑practice considerations.
This article announces the updated Spring Boot 3 case‑study e‑book with 108 examples and then dives into Java 24’s latest preview features—enhanced pattern matching, flexible constructors, module import, single‑file source, custom stream collectors, Vector API, scoped values, and structured concurrency—complete with code snippets and links.
Learn five Java file copy techniques—from basic streams to NIO Files.copy, FileChannel, and RandomAccessFile—detailing their implementations, performance differences, and ideal use cases for small, large, and massive files, helping you choose the most efficient method for your project.
This article explains how to use SpringBoot, AOP, and a custom @DataSource annotation to dynamically switch between MySQL master and slave databases, automatically falling back to the master when a slave fails, thereby achieving high availability for backend services.
This tutorial explains how to exchange the values of two Java variables without using a temporary variable, covering three techniques—arithmetic addition/subtraction, multiplication/division, and bitwise XOR—along with complete code examples, step‑by‑step explanations, output results, and discussion of each method’s advantages, limitations, and appropriate use cases.
This article explains multiple ways to load JSON configuration into Spring Boot 3 applications, covering command‑line arguments, @PropertySource with custom factories, ApplicationContextInitializer, nested JSON handling, and direct @Bean approaches, complete with code examples and troubleshooting tips.
This article explains how to build a Spring‑based download library that uses annotations to simplify downloading files, HTTP resources, or custom objects, supports both WebMvc and WebFlux, handles concurrency, compression, and event‑driven logging, and provides a modular architecture for extensibility.
Design patterns provide reusable solutions for common Java development challenges; this article explains their core concepts, categorizes creational, structural, and behavioral patterns, links them to SOLID principles, offers real‑world application scenarios, best‑practice guidelines, common pitfalls, and concrete code examples across e‑commerce, logging, and game development.
This article introduces nine different approaches to achieve asynchronous programming in Java, including using Thread and Runnable, Executors thread pools, custom thread pools, Future and Callable, CompletableFuture, ForkJoinPool, Spring @Async, message queues, and Hutool's ThreadUtil, with code examples and usage tips.
The article introduces Spring AI as an emerging tool for Java developers, explains its background, goals, and core components such as data processing, model training, deployment and monitoring, showcases application scenarios like NLP, image processing, recommendation systems and predictive analytics, and also includes promotional offers for AI resources and community groups.
The article outlines nine practical approaches for asynchronous programming in Java—including low‑level Thread/Runnable, managed Executors and custom thread pools, Future/Callable, CompletableFuture, ForkJoinPool, Spring’s @Async annotation, message‑queue integration, and the Hutool ThreadUtil utility—offering a comprehensive toolbox for scalable, non‑blocking execution.
This article introduces Spring AI, a Spring ecosystem module that simplifies building, training, and deploying AI applications for Java developers, covering its background, goals, core components such as data processing, model training, deployment, practical code examples, use cases, advantages, challenges, and future outlook.
This article presents nine practical techniques—including the Strategy pattern, lambda maps, Optional chaining, ternary operators, enums, early returns, condition merging, and rule engines—to replace cumbersome if‑else chains in Java, offering cleaner, more maintainable and performant code for Spring Boot developers.
This article explains the Facade design pattern, illustrating its purpose of simplifying complex systems with a real‑world TV remote analogy, detailing its benefits, UML structure, and a comprehensive Spring Boot example that integrates flight, hotel, and package services through a BookingFacade to streamline travel booking logic.
This guide demonstrates how to use the Fabric8 Kubernetes Java client to load, create, retrieve, update, scale, watch, and delete ReplicationController, ConfigMap, and Secret resources, providing complete code examples and step‑by‑step commands for managing these objects across namespaces in a Kubernetes cluster.
This article explains why Java performance matters, outlines fundamental principles, and provides concrete code, memory, concurrency, I/O, and database optimization techniques, along with profiling tools, common pitfalls, real‑world case studies, and emerging trends to help developers build faster, more stable applications.
This article explains how to merge multiple user‑detail requests into a single database query using a blocking queue, scheduled thread pool, and CompletableFuture in Spring Boot, providing code examples, a high‑concurrency test, and discussion of trade‑offs such as added latency and timeout handling.
This guide explains how to use JSR‑303 and Hibernate Validator in Java Spring Boot to perform comprehensive parameter validation, covering basic annotations, global exception handling, group validation, nested object checks, fast‑fail configuration, and custom validation rules, with practical code examples and testing procedures.
The article explains how high coupling caused by multiple front‑end controllers and repetitive back‑end push‑service code can be eliminated by introducing a dedicated TPS microservice that encapsulates third‑party integrations and exposes a unified Feign interface for all business systems.
After being laid off, the author interviewed only four companies, detailing each interview’s technical questions—from Spring Cloud and MySQL to concurrency and design patterns—and reflecting on the interviewers’ professionalism, the relevance of his skill set, and the importance of matching resumes to job requirements.
This article introduces Spring AI, explains its background, goals, core components such as data processing, model training, deployment and monitoring, showcases practical use cases like NLP, image processing and recommendation systems, and discusses its advantages, challenges, and future outlook for Java developers.
This article provides a step‑by‑step guide to creating a Jenkins CI/CD pipeline for Java applications, covering environment setup, required plugins, project structure, CI stages such as code checkout, dependency installation, testing, SonarQube scanning, Docker image building and pushing, as well as CD stages including Helm chart creation, deployment, health checks, rollback, and maintenance‑window management.
This article introduces a Spring Boot 3 case collection and provides a comprehensive guide to Java enums, covering their definition, type safety, custom values, interface implementation, abstract methods, generics, pattern matching, functional programming, collection usage, and sealed‑class integration with clear code examples.
This article explains the Model Context Protocol (MCP) introduced by Gitee, shows how Java developers can integrate it using LangChain4j, compares stdio and SSE transport modes, provides full code samples, installation steps, and demonstrates a practical AI‑powered repository assistant.
The Word Break problem (LeetCode 139) asks whether a given string can be segmented into a sequence of dictionary words, and can be solved efficiently with dynamic programming by tracking reachable prefixes in a boolean array, as demonstrated by concise Java and C++ implementations.
This article provides an in‑depth overview of Apache Zookeeper, covering its core concepts, common application scenarios such as pub/sub, configuration management and naming services, detailed architecture including znodes and node types, the watch mechanism, ZAB consensus protocol, and practical usage examples with Maven dependencies, Java client code, and command‑line operations.
This article walks through the One Billion Row Challenge, explaining the problem, baseline Java solution, and a series of deep performance optimizations—from parallel streams and custom hash tables to unsafe memory access and SIMD techniques—that shrink execution time from minutes to under two seconds.
Pointer collision is an efficient memory allocation technique that can trigger severe concurrency problems in multithreaded Java environments, and this article explains the underlying causes, illustrates conflict scenarios, and presents common remedies such as CAS (Compare‑And‑Swap) and TLAB (Thread‑Local Allocation Buffer) with sample code.
This article explains how to refactor the Spring MVC Controller layer by unifying response structures, using ResponseBodyAdvice for automatic wrapping, handling parameter validation with JSR‑303, and implementing custom exceptions with centralized exception handling to simplify and standardize API responses.
Explore a rich Spring Boot 3 case collection while learning step‑by‑step how to use REST‑assured for API testing, covering dependency setup, GET/POST/PUT/DELETE requests, authentication, XML validation, file upload/download, and advanced features, with full code examples and a promise of ongoing updates.
This article demonstrates how to initialize a Kubernetes Java client, configure it with default or custom kubeconfig, and provides comprehensive DSL examples for managing Pods, Services, Deployments, ReplicaSets, including creation, listing, updating, watching, port forwarding, and cleanup, with full code snippets throughout.
Oracle’s Java 24 release introduces AI‑focused enhancements such as the Vector API, new post‑quantum cryptography support with ML‑KEM and ML‑DSA, language improvements like pattern‑matching for primitives, and beginner‑friendly features, positioning Java for modern development and long‑term support.
Oracle officially released Java 24, introducing over twenty new JEPs that enhance language patterns, modular imports, AI and quantum‑resistant security, streamlined tooling, and runtime performance, while also offering a free programmer book giveaway for interested developers.
This article explains common encryption and signing algorithms—including AES, SM4, RSA2, and SM2—covers key representations in hex and Base64, details digital certificate structures, CSR application, TLS usage scenarios, OpenSSL commands for PEM conversion, and provides Java and JavaScript code examples for secure communication.
This article explains the Retrieval‑Augmented Generation (RAG) paradigm, walks through its four core steps, and provides a detailed Spring AI implementation—including configuration, vector storage, REST controller, multi‑query expansion, query rewriting, document joining, and error handling—plus best‑practice recommendations for production deployments.
The article reviews key Java backend interview topics—including thread‑safe collections, JVM memory layout and heap tuning, Full GC troubleshooting, Java 8 features, optimistic locking, stock‑over‑sell handling with Redis, MySQL scaling, cache‑consistency patterns, anti‑bot safeguards, and Bloom filters—while noting JD’s recent 30% salary hike for algorithm engineers.
This article explains how to generate a unique traceId at request entry and propagate it through Rest, MQ, and RPC modules using Log4j2, MDC, and custom converters, enabling clear, linked log output across the entire request chain.
This article explains the differences between ExecutorService and CompletionService, demonstrates how to replace a simple Future‑based approach with CompletionService for faster result retrieval, analyzes the underlying source code, and outlines typical use‑cases such as load‑balancing and early‑return patterns in concurrent Java applications.
This article provides a detailed walkthrough of Spring and Spring Boot's core concepts, explains the bean container refresh process, and enumerates all major extension interfaces—including ApplicationContextInitializer, BeanDefinitionRegistryPostProcessor, BeanFactoryPostProcessor, InstantiationAwareBeanPostProcessor, SmartInstantiationAwareBeanPostProcessor, various *Aware interfaces, @PostConstruct, InitializingBean, FactoryBean, SmartInitializingSingleton, CommandLineRunner, DisposableBean, and ApplicationListener—accompanied by code samples and usage scenarios.
An in‑depth look at how the JVM stores object references, comparing handle‑based access with direct pointer access, highlighting their performance trade‑offs, memory overhead, and impact on garbage collection to help developers choose the most suitable approach for their applications.
This article introduces a continuously updated Spring Boot 3 case collection and provides a step‑by‑step tutorial on implementing Server‑Sent Events using both the native EventSource API and the fetch‑event‑source library, covering backend controller code, frontend Vue integration, and practical code examples.
This article provides a comprehensive guide to speeding up Spring Boot application startup by explaining configuration principles, code‑level interventions, lazy loading, dependency reduction, auto‑configuration exclusion, logging adjustments, compile‑time optimizations, and caching strategies, all illustrated with practical Java examples.
This article explains OpenSSL’s origins, its role in encryption on CentOS, common use cases such as web servers and database security, provides step‑by‑step installation and upgrade commands, and demonstrates how to generate RSA, SM2, AES, and SM4 keys via the OpenSSL command line and Java alternatives.
This article explains how Java's foreach loop is implemented using iterators, demonstrates the bytecode differences between array and collection traversal, analyzes why modifying a HashMap during foreach can trigger ConcurrentModificationException, and shows the correct way to safely modify collections with an iterator.
This article explains how to refactor the Spring MVC Controller layer by standardizing response structures, implementing unified response wrapping via ResponseBodyAdvice, handling String conversion issues, applying JSR‑303 parameter validation, creating custom validation rules, and defining custom exceptions with centralized exception handling to simplify controller code.
The article recounts a puzzling case where a minimal Java program using ConcurrentLinkedQueue runs fine normally but throws a NullPointerException when debugged in IntelliJ IDEA, explains the underlying cause involving the IDE's automatic toString invocation, and shows how to disable the offending settings.
This article explains how SpringBoot integrates MyBatis by using @MapperScan and @Import annotations to scan mapper interfaces, generate and modify BeanDefinitions, create proxy beans, and execute SQL statements, while also promoting AI tools, DeepSeek resources, and related services for developers.
This article explains the motivation behind Netty's FastThreadLocal, details its internal design using an indexed array to avoid hash collisions, analyzes the core source code of InternalThreadLocalMap, FastThreadLocalThread, and FastThreadLocal, and discusses performance implications and reclamation strategies.
The article compares Java and Go across syntax, variable declaration, object‑oriented features, error handling, concurrency models, garbage collection, resource usage, and ecosystem maturity, concluding that Go offers simpler code, lightweight concurrency and lower overhead, while Java provides a richer library ecosystem and more mature tooling, making the choice dependent on project requirements.
Amid the AI wave, Java backend developers focused solely on CRUD face replacement by automation, but by deepening business expertise, enhancing soft skills, gaining project experience, and expanding into AI and new technologies, they can transform their roles and stay valuable in the evolving software industry.
This article explains how to use spring-smart-di to dynamically switch between multiple service providers in a Spring application, reducing manual configuration, improving fault tolerance, and enabling runtime updates without restarting the service.
This article explains how to dynamically switch between multiple service providers in a Spring backend by configuring identifiers, using spring-smart-di's AutowiredProxySPI and related annotations, and provides step‑by‑step code examples for seamless, runtime‑configurable dependency injection.
Web containers, such as Tomcat, keep running by continuously listening on network ports with socket servers and thread pools, handling I/O requests; this article explains the role of the main function, servlet lifecycle, Netty’s NIO framework, and why WebFlux‑based gateways outperform traditional Tomcat setups.
This article presents a comprehensive overview of using static analysis and change‑impact techniques—including program slicing, variable lineage, and automated field mapping—to reduce risk‑related incidents in large‑scale financial systems by more than 50%, outlining the background, solution architecture, implementation steps, and optimization challenges.
This article explains how to size and configure JVM options—including heap size, young generation, GC algorithm, thread stack, and metaspace—for a backend service that processes one million login requests per day on an 8 GB machine, providing step‑by‑step calculations, practical examples, and optimization tips.
This article demonstrates how to use Spring AI with a large language model to automatically generate and execute SELECT SQL statements in a Spring Boot 3 application, covering dependency setup, configuration files, prompt templates, controller implementation, and testing with example scripts.
This article provides a detailed Java backend interview guide covering Redis cache problems and solutions, Spring Boot startup process, common annotations, Git workflow commands, Java exception hierarchy, Java 8 enhancements, HashMap implementation, Docker containerization, and Jenkins CI/CD practices, along with practical examples and code snippets.
Quarkus, a Kubernetes‑native Java framework built for GraalVM and HotSpot, delivers millisecond startup, low memory usage, developer‑friendly features, and seamless integration with cloud‑native platforms, making it ideal for microservices, serverless, and modern cloud applications.
This article explains how to compress large objects with GZIP before storing them in Redis, demonstrates the pitfalls of not closing streams, shows how Java's try‑with‑resources simplifies resource management, and provides best‑practice code examples to prevent hidden IO exceptions.
This article introduces annotation‑based parameter validation in Spring Boot 3, explains built‑in constraints, shows how to use @Valid and @Validated in controllers, and provides multiple practical code snippets—including record types, error handling, collection validation, and return‑value checks—along with screenshots of validation errors.
The article describes how a Java-based supermarket checkout performance test was refined by adding gender-specific rest intervals—2 minutes for male cashiers and 5 minutes for female cashiers—through code changes that introduce a gender attribute, rest logic, and integration into the test workflow.
This article explains Java object pooling using Commons Pool 2 and HikariCP, covering their core classes, configuration parameters, practical examples with Redis and JDBC, interview questions, and JMH performance benchmarks that demonstrate significant throughput improvements.
The article explains how to avoid tangled if‑else code in a Java backend by using a process engine and a plugin‑based extension point framework, detailing interface definitions, annotations, loading mechanisms, and usage examples drawn from the open‑source MemberClub project.
The article compares Spring Boot and Quarkus for cloud‑native Java apps, showing Quarkus’s faster startup, smaller builds and lower memory usage (especially in native mode) while Spring Boot slightly leads latency, and outlines migration paths leveraging Quarkus’s Spring‑compatible extensions and native‑image advantages.
The article explains why simple code quickly becomes unmanageable in multi‑business systems, introduces workflow engines and plugin extensions as solutions, and demonstrates configuration, node definition, execution, and the underlying Java implementation to achieve clean, isolated, and extensible business logic.
Explore the newly released Spring Boot 3 case collection and dive into a practical guide on implementing API version control in Spring 7.0.0‑M3, featuring step‑by‑step configuration, Maven setup, custom version resolver, and annotated controller examples, plus a promise of ongoing updates.
This article provides a concise guide on using SpringAI to connect Java applications with the domestic large‑language model DeepSeek, covering design philosophy, configuration, code examples for chat, streaming, structured output, security hardening, performance tuning, and production best practices.
The article revises a supermarket checkout performance test by incorporating elderly customers who take twice as long to pay, demonstrates using Java's ThreadLocalRandom to randomly assign customer age groups, modifies the pay() method to double payment time for seniors, and explains why realistic scenarios improve testing accuracy.
RocketMQ’s message tracing feature records each message’s full lifecycle—including producer, broker, and consumer details such as timestamps, latency, and success flags—by enabling traceTopicEnable, creating an internal RMQ_SYS_TRACE_TOPIC, and allowing custom trace topics for fast diagnostics, end‑to‑end tracking, monitoring, and audit compliance.
This article compares Spring Boot and Quarkus across architecture, startup speed, memory usage, and native image support, presents a JMeter‑based performance test suite, shares migration tips for Spring developers, and provides concrete Java code examples for building reactive microservices on both frameworks.
The article examines Java thread states—WAITING and TIMED_WAITING—through monitoring screenshots, explains their definitions, trigger conditions, and recovery mechanisms, analyzes real‑world code involving concurrent tasks, and presents flame‑graph based performance optimizations for backend services.
This article explains Java thread run states, analyzes why threads appear in WAITING or TIMED_WAITING during concurrent tasks, shows flame‑graph diagnostics, and offers concrete code‑level optimizations to reduce CPU pressure and improve overall backend performance.
This article explores eight common scenarios for using message queues in backend development, covering asynchronous processing, service decoupling, traffic shaping, delayed tasks, log aggregation, distributed transactions, remote calls, and broadcast notifications, each illustrated with Java, RocketMQ, and Kafka code examples.
This curriculum outlines a 25‑week advanced Java engineering program covering performance optimization, JVM internals, concurrency, distributed storage, MySQL and NoSQL databases, Docker, Kubernetes, microservices, Spring framework deep dives, Nginx, Elasticsearch, Redis, messaging systems, CI/CD tools, and hands‑on project implementation to build high‑performance, scalable backend systems.
This article explains how Spring's ResponseBodyEmitter, introduced in Spring 4.2, enables lightweight asynchronous HTTP streaming for use cases like real-time logs, progress updates, chat, and AI responses, and provides a complete code example with best-practice guidelines.
This article explains the CRaC (Coordinated Restore at Checkpoint) technology for Java applications, describing its principles, supported environments, practical steps for enabling it with Spring Boot, and use‑case scenarios that dramatically reduce JVM startup time.
Modern Java introduces lambda expressions and the Stream API for functional programming, while upcoming projects—Loom’s virtual threads, Panama’s foreign function and memory API, and Valhalla’s value classes and generic specialization—address concurrency, native interop, and performance, dramatically enhancing developer productivity and language capabilities.
This article introduces the advantages of Java's CompletableFuture and systematically outlines six common pitfalls—including default thread‑pool issues, exception handling, timeout management, thread‑local context loss, callback hell, and task‑ordering problems—while providing correct code examples and best‑practice recommendations.
This article introduces JDFrame/SDFrame, a Java library that provides a DataFrame‑style, semantic API for JVM‑level stream processing, demonstrates quick start with Maven dependency, and showcases extensive examples covering filtering, aggregation, distinct, grouping, sorting, joining, partitioning, ranking, and data replenishment, helping developers write concise, readable data‑processing code.
This article explains Java's two primary garbage‑collection techniques—reference counting and reachability analysis—detailing their principles, drawbacks such as circular reference issues, and why modern JVMs favor reachability analysis to safely reclaim memory.
This article introduces JavaParser, an open‑source library for parsing Java source code into an AST, and walks through practical cases covering dependency setup, basic parsing, class and method extraction, code modification, class generation, and comprehensive analysis with code snippets and output screenshots.
This article explains how Spring's declarative transaction management works, why the @Transactional annotation can unexpectedly become ineffective, and presents twelve typical scenarios—such as internal method calls, non‑public methods, final/static modifiers, proxy issues, and incorrect propagation settings—along with practical solutions to ensure reliable transaction handling.
This article introduces JSONPath as a query language for JSON, explains its core concepts and basic syntax with examples, demonstrates various practical use cases such as data extraction, API testing, and shows tool support across Python, Java, and JavaScript.
Facing the need to query multiple databases in a Spring Boot application, this guide walks through building a custom dynamic datasource solution using ThreadLocal and AbstractRoutingDataSource, covering core implementations, annotation‑based switching, dynamic datasource addition, configuration, and comprehensive test results.
This guide explains how to create a shell script to deploy a Java backend application without Docker, covering variable configuration, start/stop/restart functions, log handling, and command-line usage, along with packaging and troubleshooting steps.
This article provides a comprehensive, English-language walkthrough of MyBatis's four core components—Executor, StatementHandler, ParameterHandler, and ResultSetHandler—explaining their interfaces, default implementations, key methods, and how they collaborate to translate Java objects into SQL statements and process query results.
Discover ten validated Spring Boot 3 performance optimization techniques—including lazy initialization, JVM tuning, connection pooling, caching, async processing, virtual threads, and Actuator monitoring—complete with configuration snippets and code examples, to accelerate startup, reduce memory usage, and improve response times for Java backend services.
This article introduces Magic‑API, a Java‑based rapid API development framework, outlines its extensive feature set, and provides step‑by‑step instructions—including Maven integration, configuration, and visual UI usage—to help developers create HTTP endpoints without writing traditional controller or DAO code.
This article introduces AviatorScript, a lightweight high‑performance JVM‑based scripting language, outlines its core features and limitations, demonstrates how to add it to a Maven project, shows expression evaluation, variable handling, custom functions, script files, and provides a practical Spring Boot AOP validation example with full code snippets.
The article explains the concept of GC Roots in the JVM, detailing the four main types—stack variables, static fields, constant pool references, and JNI references—along with code examples, and describes how these roots determine object liveness during garbage collection.
This article walks through a step‑by‑step troubleshooting process for JVM Out‑Of‑Memory (OOM) incidents, covering symptom identification, monitoring tools like top, jstat, and jmap, root‑cause analysis, and actionable recommendations to prevent future memory leaks.
This article explains how Spring Boot 3's new @BindParam annotation lets developers map mismatched path and query parameters to constructor arguments, supports @ModelAttribute, and shows how to create custom name resolvers for advanced parameter binding scenarios.
This article demonstrates how to integrate Apache Tika into a Spring Boot application to automatically extract file content, detect sensitive data such as ID numbers, credit cards, and phone numbers using regex, and implement data leakage protection through RESTful file upload endpoints and optional front‑end UI.
The article explains why excessive if‑else logic harms maintainability, introduces flow‑engine and plugin‑extension techniques to isolate business code and enable flexible extensions, demonstrates their implementation in the open‑source MemberClub project with configuration, node definitions, execution flow, and source code examples.
This article demonstrates how to dramatically speed up Java data‑matching operations that use nested for‑loops by breaking early when a match is found and by converting the inner list into a HashMap for O(1) lookups, showing code examples, performance measurements, and practical tips for backend developers.
This article explains the Java BigDecimal class, its internal fields, and how its addition method scales numbers to maintain precision, illustrated with code examples and debugging insights, concluding that BigDecimal performs arithmetic using scaled long integers to avoid precision loss.
