The article explains how to achieve graceful shutdown of Spring Boot services by handling Linux kill signals, registering JVM shutdown hooks, and exposing an Actuator REST endpoint that safely releases resources, stops beans, and terminates the JVM without data loss.
This article explains the six Java thread states defined in java.lang.Thread.State, describes the meaning of each state, illustrates the possible state transitions, and provides three runnable code examples that demonstrate NEW, RUNNABLE, BLOCKED, WAITING, TIMED_WAITING and TERMINATED states along with their console outputs.
This article explains the concepts of Data Transfer Object (DTO), Business Object (BO), Persistent Object (PO), and Value Object (VO) in backend development, shows how they differ and interact across layers, and provides Java code examples and a global configuration to filter null fields during serialization.
This article explains the challenges of integrating diverse tools without MCP, then demonstrates step‑by‑step how to configure Spring‑AI and the native MCP SDK to call LLMs, register tools, handle SSE and stdio services, and troubleshoot common issues, providing code snippets and best‑practice recommendations.
This article walks you through using Spring AI's MCP client starter in a Spring Boot 3 project to connect to Baidu Map's MCP server, covering dependencies, YAML and JSON configurations, communication modes, custom server setup, and sample code for invoking the service.
When handling complex forms in SpringBoot, developers often write repetitive code to extract each field, but the @ModelAttribute annotation automatically binds all form parameters to Java objects, reducing boilerplate, improving readability, and supporting custom binding scenarios.
This article analyses why Spring Boot startup can take dozens of seconds, breaks down the most time‑consuming phases such as prepareEnvironment and refreshContext, shows profiling code and screenshots, compares a simple MVC demo with a real‑world project, and identifies external client connections and configuration loading as the biggest bottlenecks.
This article shares ten practical rules for producing high‑quality logs in Java backend systems, covering unified formatting, stack traces, log levels, complete parameters, data masking, asynchronous logging, traceability, dynamic level adjustment, structured storage, and intelligent monitoring to help developers quickly diagnose issues and improve system reliability.
This article explains how to split a multi‑function OpenAPI endpoint into independent steps using the responsibility‑chain pattern in Spring, detailing the abstract component, context sharing, bean retrieval via ApplicationContext, and a controller that dynamically orders execution through a query parameter, with full code examples.
This article explains why consistent Java code style matters, reviews major industry standards such as Google and Alibaba, guides the selection and customization of a style guide, and demonstrates how to configure IntelliJ IDEA, Checkstyle, and Maven to enforce the rules throughout development.
This article explores the importance of Java code style guidelines, compares major industry standards such as Google Java Style and Alibaba's conventions, and provides step‑by‑step instructions for configuring IDEs and Maven plugins to enforce consistent, readable code across teams.
This article explains how using a custom @DistributeLock annotation together with @Transactional can cause idempotency issues due to aspect execution order, and demonstrates how to prioritize the lock aspect using @Order to ensure the lock is applied before the transaction, with code examples and best‑practice recommendations.
This article explains how to efficiently handle exceptions in Spring Boot applications by using @ControllerAdvice and @ExceptionHandler annotations, providing step-by-step code examples for custom global exception classes, error response structures, and handling specific exceptions such as business, null pointer, and type conversion errors.
This article explains how to use the poi‑tl Java library to create Word report templates, define common tags such as text, images, tables, lists, and charts, encapsulate them with enums and factories, and generate complete reports through a reusable utility class.
During a major promotion a huge activity generated an oversized Redis cache key that caused cache‑penetration, saturated network bandwidth, and triggered a cascade of service failures, prompting a detailed root‑cause analysis and a set of mitigation and prevention measures.
This article explains how to design, configure, and operate an Activiti workflow engine in a Java Spring Boot application, covering BPMN diagram creation, engine setup, deployment, task handling, code examples, API usage, and comparisons with other workflow solutions.
This article provides an in‑depth analysis of the Java ConcurrentHashMap implementation, covering its constructor logic, hash‑table sizing, the core put and get operations, element counting with addCount, multi‑threaded resizing via transfer, treeification of bins, removal, computeIfAbsent, and the design choices that forbid null keys and values to simplify concurrency handling.
This article provides a thorough, English‑language walkthrough of Java 8+ ConcurrentHashMap’s source code, covering its constructor logic, load‑factor handling, CAS‑based insertion, node optimizations, the put method, element‑count updates, multi‑threaded resizing, treeification, and auxiliary operations such as get, remove, and computeIfAbsent.
The article examines why many programmers favor if...else over switch statements, outlining switch's intended clarity, its limitations such as lack of range support and fall‑through pitfalls, performance considerations across languages, and scenarios where each construct shines.
This article explains why both front‑end and back‑end data validation are essential for secure and user‑friendly web applications, introduces Java Bean Validation annotations, shows how to integrate them with Spring MVC, and compares common Java permission‑control frameworks such as Spring Security, Shiro and Sa‑Token.
This article demonstrates how to use Java 8's Function and SFunction functional interfaces together with lambda expressions to abstract and reuse data‑validation logic, dramatically reducing repetitive code, improving readability, and enabling flexible, generic validation across various backend entities.
This article provides a comprehensive guide for Android developers on how to connect and use serial ports, USB peripherals, printers, barcode scanners, payment boxes, keyboards, and mice, including required permissions, configuration steps, and sample Kotlin/Java code snippets for each device type.
This article introduces Spring Cloud Gateway as a high‑performance replacement for Zuul, explains its core components (Route, Predicate, Filter) and request flow, provides step‑by‑step setup of a gateway project, demonstrates route configuration, custom GlobalFilter and GatewayFilter implementations, and validates the behavior with example requests.
This article explains the behavioral Strategy design pattern, describes its definition and structure, demonstrates a real‑world e‑commerce discount scenario with both a tangled if‑else implementation and a clean refactoring using Java interfaces, concrete strategy classes, a context, and a client, and finally discusses its advantages and drawbacks.
This article presents six commonly used file upload and download techniques for Spring Boot, covering basic Multipart handling, stream-based download, integration with Alibaba Cloud OSS and MinIO, as well as high‑concurrency chunked uploads with Nginx, each accompanied by complete code examples and usage scenarios.
This tutorial shows how to build and run a Spring MVC application using an embedded Tomcat server with just a single Java class, covering Maven dependencies, Tomcat configuration, Servlet registration, Spring‑driven startup, and core Spring MVC component setup.
When a midnight CPU alarm triggered, I logged into the server, identified runaway Java processes, profiled the JVM, refactored a costly sorting algorithm, added database indexes, containerized the service, and set up Prometheus alerts, ultimately reducing CPU usage below 30% and restoring millisecond response times.
This article explains how to build a high‑performance Netty‑based WebSocket client for large‑scale performance testing, covering Netty fundamentals, custom handler implementation, client bootstrap configuration, message sending, connection closing, batch operations, and client encapsulation to reduce resource consumption and improve scalability.
This article explains how SpringBoot’s @DateTimeFormat annotation automatically converts timestamps and date strings to Date, LocalDate, or LocalDateTime objects, eliminating manual parsing code, and provides practical examples ranging from simple date parameters to custom datetime patterns for more efficient backend development.
This article explains why API debounce is needed in web back‑ends, identifies the types of endpoints that require it, outlines how to detect duplicate requests, and provides two concrete distributed solutions—shared Redis cache and Redisson lock—complete with annotation design, key generation logic, and full Java code examples.
This article provides a comprehensive walkthrough of building a Java WebSocket client, covering client creation, connection establishment, message sending, graceful closure, header handling, and code encapsulation, with complete example code and best practices for performance testing and robust error handling.
Explore how to leverage JSR‑330 standard annotations such as @Inject, @Named, and @ManagedBean in Spring Boot 3.4.2, with practical code examples, dependency setup, bean naming, optional injection, and a comparison of their limitations versus native Spring annotations.
This article explains how to use Spring Boot Actuator to monitor and control Spring Cache, covering essential cache annotations, a complete CRUD example with caching, cache management endpoints, custom CacheManager configuration, and optional Redis integration for production‑grade caching.
This article explains how programming‑language memory models define the guarantees for shared‑memory concurrency, illustrates common pitfalls such as ordinary‑variable problems and instruction‑reordering, and surveys the evolution of memory models in Java, C++, Rust, Swift, JavaScript and hardware architectures.
The article explains Hibernate's @Formula annotation, showing how to define dynamic, read‑only fields with SQL expressions, provides code examples for simple concatenations, aggregate calculations, and multi‑table integrations, and offers best‑practice guidelines to optimize performance and avoid common pitfalls.
Spring Boot's @SessionAttributes annotation enables automatic session data handling, eliminating repetitive HttpSession code, simplifying development, improving maintainability, and supporting multi-attribute management and cleanup, as demonstrated through detailed examples and best practices for user login and shopping cart scenarios.
This guide explains how to locate the cause of sudden CPU spikes in a Java program by using the top command to identify the offending process and thread, converting the thread ID to hexadecimal, and analyzing stack traces with jstack to pinpoint the problematic code line.
This article examines the design of Netty's FastThreadLocal, compares its performance and memory‑management advantages over Java's ThreadLocal, and outlines suitable high‑concurrency use cases, implementation details, and practical considerations for developers.
This guide explains how to use the JXLS Java library to create complex, template‑driven Excel reports, covering setup, core concepts like XlsArea, looping, conditional rendering, dynamic grids, merging cells, image insertion, and formula handling with practical code examples.
This article examines the evolution of Java's HashMap from head‑insertion in JDK 1.7 to tail‑insertion in JDK 1.8, explains how the change eliminates circular‑list deadlocks during concurrent resizing, discusses remaining concurrency pitfalls such as red‑black tree conversion, and offers best‑practice solutions like using ConcurrentHashMap and proper initial capacity settings.
This guide walks through practical RBAC design using Sa-Token, providing MySQL table schemas for users, roles, permissions, sample data, and Spring Boot API code for authentication, authorization checks, and retrieving the logged‑in user's details.
This article presents a comprehensive collection of 124 Spring Boot 3 practical cases, detailing eight distinct methods for defining web interfaces—including @Controller, @RestController, HttpRequestHandler, ServletRegistrationBean, HandlerFunction, @HttpExchange, and static resource registration—complete with code snippets, configuration steps, and usage explanations.
This article introduces an open‑source Java JSON framework that uses recursive parsing and reflection to serialize and deserialize objects without third‑party libraries, supports generic and array types, and provides extensible features such as custom annotations, JsonPath, and HTML‑safe output.
The article explains how the SpringBoot @PageableDefault annotation automatically provides default pagination parameters, reducing boilerplate code, improving readability, and offering flexible control for various query endpoints in Java backend development.
This article explains how Java's Stream API enables efficient data processing through pipeline operations such as filter, map, flatMap, stream creation methods, conversion to collections, and parallel execution, providing code examples and practical usage guidelines.
This article explains how Spring Boot’s default embedded Tomcat container can be replaced with the high‑performance Undertow server, provides step‑by‑step Maven configuration, compares their performance and memory usage, and concludes with a recommendation for high‑concurrency applications while also containing promotional material for AI services.
This guide shows how to create a reusable BaseController using MyBatis‑Plus, reflection utilities, and Spring Boot annotations to provide automatic CRUD, list, pagination and count endpoints for any entity with minimal code.
The article first highlights Tencent's Q1 2025 financial results and user metrics, then introduces the LeetCode 2013 'Detect Squares' problem, describing its requirements, example, and offering Java, C++, Python, and array‑based solutions along with time and space complexity analysis.
This article demonstrates how to automate CRUD functionality in a Spring Boot application by adding MyBatisPlus, creating utility methods for query building and reflection, implementing a generic BaseController, configuring pagination support, and extending the controller for specific entities, providing a reusable RESTful API template.
This tutorial demonstrates how to add Apache POI dependencies via Maven and use Java code to create an Excel workbook containing a multi‑series temperature line chart, including custom font sizes for titles and axes, and finally export the file to disk.
This article introduces Sentinel, a cloud‑native flow‑control component born from Alibaba's ecosystem, explains its resource‑based rule model, core implementation—including rule‑control chain, datasource, and dashboard—and discusses practical deployment considerations and extension strategies for Java microservices.
After caching, indexing, and async optimizations still leave a Spring Boot REST API sluggish, this guide shows how fine‑tuning JVM options—such as enabling G1GC, adjusting pause targets, compressing class metadata, shrinking thread stacks, and pre‑touching memory—can triple response speed without changing application code.
This article explains the internal mechanism of HashMap traversal in Java, detailing how keySet() leads to two iteration steps via an iterator, while entrySet() and Map.forEach() provide a single-pass iteration, and examines the underlying iterator classes and their constructors.
This article explains a complete, reusable solution for recording operation logs in Java backend applications using Spring AOP, custom annotations, callback interfaces, and a user‑adapter to bridge third‑party logging libraries with the main program, enabling flexible storage and auditing.
Facing frequent timeouts in a high‑throughput Java service, we traced instability to long GC pauses during massive index swaps, then systematically tuned JVM parameters, explored G1, ZGC, and custom Eden‑pre‑heating techniques, ultimately achieving near‑perfect availability without adding hardware.
This article explains what makes a class thread‑safe in Java, illustrates common race‑condition pitfalls with sample code, and presents six practical design strategies—including stateless, immutable, synchronized, volatile, concurrent collections, thread‑confinement, and defensive copying—to help developers build robust, high‑performance concurrent applications.
This article explains how SpringBoot's @RequestHeader annotation automatically binds HTTP request headers to controller method parameters, reducing boilerplate code, supporting default values and optional headers, and improving readability and development efficiency with clear code examples.
This article explains how to store and inject collection types such as List, array, Set, and Map in Spring configuration files, demonstrates the pitfalls of using @Value directly, and provides practical solutions using @ConfigurationProperties, EL split functions, and custom decoders for flexible and safe property binding.
From Google's early recruitment challenges to acquiring a tiny startup that built a Java‑based demo system, Android emerged as an open‑source mobile operating system, leveraging Dalvik, overcoming hardware competition, and ultimately dominating the global smartphone market through rapid development and strategic alliances.
This article introduces the six main types of interceptors in SpringBoot—Filter, HandlerInterceptor, AOP, RestTemplate, Feign, and WebFilter—explaining their typical use‑cases, implementation details, common pitfalls, and best‑practice ordering to help developers choose the right tool for each scenario.
This article explains why finalize() was deprecated, introduces the Java Cleaner API, compares it with reference types and try‑with‑resources, provides practical code examples, and offers guidelines to use Cleaner effectively while avoiding common pitfalls.
The article explains how IntelliJ creates a debug session via XDebuggerManager.startSessionAndShowTab, the role of XDebugSession and XDebugProcess, and details the sequence of events and listeners involved when the session is stopped, including process termination and listener cleanup.
This tutorial explains how Objenesis enables Java objects to be instantiated without invoking constructors, covering traditional object creation, the library’s internal mechanisms, Maven setup, usage examples with ObjenesisStd, ObjenesisSerializer, and ObjenesisHelper, advanced scenarios, best practices, and considerations for safe adoption.
This article explains how Java developers can replace thousands of individual UPDATE statements with a single PostgreSQL stored procedure call, covering the motivation, procedure creation, Java invocation, scheduling with shell scripts, performance benchmarks, and common pitfalls.
This article explains how to extract AOP annotation code, implements a Redis-based rate limiter using Redisson in Java, analyzes the underlying Lua script, and extends the utility to support automatic expiration of the limiter, providing complete code examples and detailed explanations.
Explore 15 practical Java Stream API examples—from filtering and mapping to parallel processing and JPA integration—demonstrating how to write concise, efficient code, improve performance, and avoid memory issues, with full code snippets and explanations for each use case.
This guide demonstrates how to protect a Spring Boot service from malicious requests by creating a custom interceptor that tracks URL‑IP request counts, uses Redis for distributed locking, and disables offending IPs after a configurable threshold, with full code examples and configuration steps.
The article explains how the SpringBoot @Timed annotation can automatically record method execution times, replacing verbose manual timing code, and demonstrates basic and advanced usages with custom metric names and tags to simplify performance monitoring in backend development.
Maven‑mvnd introduces a long‑running daemon to eliminate JVM startup overhead, cut resource usage, accelerate frequent builds, and streamline multi‑module projects, while remaining compatible with existing Maven workflows and offering GraalVM‑based native execution for faster, lighter builds.
This article explains the various ways to traverse a Java HashMap, compares keySet and entrySet approaches, shows why keySet involves two passes, and demonstrates the underlying iterator implementation with detailed code examples and decompiled snippets.
This article explains the concept of SaaS multi‑tenant architecture, compares three data‑isolation designs, and demonstrates how to implement elegant tenant‑level data isolation in Java using MyBatis‑Plus’s tenant plugin, complete with configuration, handler code, SQL examples, and troubleshooting tips.
This article introduces the SootUp library, explains how to configure its Maven dependencies, describes the Jimple intermediate representation, and demonstrates how to use SootUp's API to analyze Java source code, bytecode, and method bodies through a series of code examples.
This guide walks through using Frida to hook common Android methods, print stack traces, and extract runtime data, providing ready-to-use code snippets for functions like HashMap.put, ArrayList.add, TextUtils.isEmpty, Base64 encoding, and UI event handling.
The article outlines common backend code smells such as over‑engineering, deep inheritance hierarchies, excessive DTO/VO layers, unnecessary interfaces, and contract‑less microservice designs, explains why they harm team efficiency and project quality, and provides concrete Java examples and best‑practice recommendations to avoid them.
This article describes a utility method that leverages Java reflection and generics to automatically generate a MyBatis-Plus QueryWrapper from a DTO, handling field‑name mapping, type‑specific query conditions, and camel‑to‑snake case conversion for seamless database queries.
A ToB Java service that initially expected 500 requests per second fell to only 50 RPS under load, prompting a step‑by‑step investigation of CPU usage, lock contention, slow SQL, excessive logging, prototype‑scoped beans, and thread‑pool configuration, ultimately revealing how bean creation and async execution affect throughput.
The article demonstrates that synchronizing on a locally created object does not provide proper thread safety, shows the resulting chaotic output, and explains how moving the lock object to a class field resolves the issue, illustrated with Java code and debugging screenshots.
This article introduces Spring AI, explains its core features for integrating various AI models, and walks through creating a Spring Boot chat application that connects to the DeepSeek model using both synchronous and streaming endpoints.
This article explains the purpose, advantages, design principles, configuration parameters, task queue options, rejection policies, lifecycle management, and internal execution flow of Java's ThreadPoolExecutor, providing code examples and detailed insights into how thread pools work in concurrent applications.
This article walks through integrating SpringBoot, Dubbo, and Seata to implement reliable distributed transactions, covering project setup, Maven dependencies, service definitions, Nacos registration, configuration files, testing normal commits and rollbacks, and troubleshooting version incompatibilities.
This article explains why feature flags are essential in Spring Boot projects and walks through six concrete ways to implement dynamic toggles—including @Profile, @Conditional, @RefreshScope, database‑backed scheduling, Apache Commons Configuration, and Togglz—complete with code snippets and usage tips.
The article explains how SpringBoot's @ResponseStatus annotation can automatically set HTTP response status codes for methods and custom exceptions, reducing boilerplate code, improving maintainability, and offering flexible error handling, with practical examples and best‑practice guidelines.
Abstract classes and interfaces are core object‑oriented concepts that enable reusable, extensible, and maintainable code; this article explains their definitions, design considerations, and real‑world applications, illustrated with Java examples of a Control hierarchy and a Shape interface implementation.
This article explains how Java 8 functional interfaces such as Function, Supplier, Consumer, and Runnable can replace repetitive if‑else statements, provides code examples for throwing exceptions, branch handling, and present‑or‑else logic, and demonstrates practical usage to improve backend code readability.
The article introduces the custom @ViewController annotation for Spring Boot, explains how it simplifies conditional view selection compared with manual if‑else logic, provides basic and advanced code examples, lists its advantages, and shows real‑world usage in an e‑commerce project.
This article introduces Java 21 virtual threads, demonstrates their basic creation and delayed start, shows how to enable and configure them in Spring Boot, compares performance against traditional threads with benchmark results, and provides additional Java performance optimization techniques.
This article explains how Java's synchronized keyword works, covering object and class locks, lock upgrades such as biased, lightweight, and heavyweight locks, the underlying monitor implementation, example code for a thread‑safe counter, and performance considerations for high‑concurrency scenarios.
This guide explains how to configure a Maven pom.xml file, covering project coordinates, dependency scopes, dependencyManagement, exclusions, conflict resolution, lifecycle phases, goals, common plugins, profile activation, repository settings, distribution management, and modular project structure for reliable Java builds.
JManus is an open‑source, Java‑centric AI agent platform built on Spring AI Alibaba that lets developers quickly create, configure, and run multi‑agent applications with support for major large language models, a web UI, and advanced PLAN‑ACT reasoning capabilities.
Spring Boot's @ConversionService annotation simplifies request parameter conversion by automatically transforming string inputs into target types such as dates or numbers, eliminating repetitive manual parsing code, supporting custom converters, and enhancing code maintainability and development efficiency, as demonstrated with practical examples.
After a login module unintentionally redirected users to a gambling site, the author explains how maliciously crafted redirect parameters enable HTTP redirect attacks, demonstrates vulnerable Java code, and outlines three defensive layers—whitelisting, signature verification, and path sanitization—plus five best‑practice tips to prevent such exploits.
This article explains how to configure MyBatis for dynamic SQL using XML mapper files and annotation-based methods, provides step‑by‑step code examples, and compares the advantages and disadvantages of each approach to help developers choose the best solution for their projects.
The Dromara mica-mqtt 2.4.5 release introduces Maven groupId changes, custom deserialization for @MqttClientSubscribe, numerous bug fixes, enhanced Android compatibility, snapshot support, and detailed migration documentation, while also showcasing BladeX IoT platform best‑practice examples.
This article explores the hierarchy of Spring Boot interception mechanisms—Filter, HandlerInterceptor, AOP, RestTemplate, Feign, and WebFilter—detailing their typical use cases, implementation code, pitfalls, and best‑practice ordering, while providing practical tips and performance monitoring advice for robust backend development.
This article demonstrates how to use the H2 database with Java 1.8, covering embedded (file and memory) modes, server modes (Web, TCP, PG), mixed mode configurations, required dependencies, and provides complete JUnit test code examples for creating, accessing, and managing tables.
This tutorial demonstrates how to create a complete meeting‑management CRUD application using Spring Boot 3, Spring AI Tools, and a custom ChatClient, covering environment setup, entity definitions, repository, service layer, tool integration, and REST endpoints with code examples and screenshots.
This article explains the concepts of Data Transfer Object (DTO), Business Object (BO), Persistent Object (PO), and Value Object (VO) in backend development, compares their roles, provides Java code examples, and discusses how to configure Spring MVC to filter null fields, while also including promotional content for IDE licenses.
This article explains how the @Encrypt annotation in SpringBoot can automatically handle encryption and decryption of sensitive API parameters, eliminating repetitive manual code, improving maintainability, and allowing custom encryption strategies for real‑world applications.
The article explains Maven‑mvnd, a daemon‑based Maven variant that eliminates JVM startup overhead, reduces resource consumption, and speeds up single‑ and multi‑module Java builds, while remaining compatible with existing Maven workflows and offering simple installation, configuration, and usage instructions.
This article introduces nine indispensable Java utility classes—including Collections, CollectionUtils, Lists, Objects, StringUtils, BeanUtils, ReflectionUtils, DigestUtils, and HttpStatus—showing how each can simplify common tasks, reduce boilerplate code, and improve development efficiency with clear examples and code snippets.
