This tutorial explains how to use Spring Retry in a SpringBoot 2.7 application, covering both annotation‑based @Retryable usage and programmatic RetryTemplate configuration, with complete code examples, listener implementation, and execution results.
This article demonstrates how to apply the Strategy pattern combined with a simple factory in a Spring Boot application, showing interface definition, multiple arithmetic strategy implementations, a factory that registers beans, a service invoking strategies via a map, and a REST controller for testing, highlighting extensibility.
This article explores the evolution of business operation logging in a Java backend, starting from a simple AOP‑annotation approach, advancing to AOP combined with Spring Expression Language for richer context, and finally leveraging MySQL binlog with time‑window processing to achieve comprehensive, low‑intrusion audit trails.
This article demonstrates how to create a custom insertable annotation processor in Java to automatically inject the jar version into component constants at compile time, eliminating manual updates and enabling Prometheus monitoring of library usage across versions.
This article walks through a step‑by‑step interview scenario where a candidate solves the classic Two Sum problem, starting with a naïve nested‑loop approach, then improving it using a hash‑map to achieve linear time complexity, and discusses edge cases and code refinements.
This article details how to dramatically speed up the import of massive Excel files (over 100,000 rows) into a Java backend by switching to EasyExcel, caching database lookups, using batch VALUES inserts, and parallelizing the write operations with functional utilities.
This article explains the concept of AVL self‑balancing binary search trees, outlines their height‑balancing property, and provides step‑by‑step Java code examples defining a Node class implementing Comparable and an AVLTree class with height, balance factor calculations, and rotation methods for insertion and deletion.
This article explains the concept of idempotency, identifies which API requests are naturally idempotent, discusses why idempotency is essential for retries, asynchronous callbacks, and message queues, and provides a step‑by‑step Java Spring implementation using custom annotations, AOP, and Redis for token management.
This article provides a step‑by‑step guide on integrating the lightweight distributed task scheduler XXL‑JOB into a SpringBoot application, covering prerequisite installations, Maven dependency configuration, property settings, JobHandler implementation, and registration to enable scalable and reliable job execution.
Aspect-Oriented Programming (AOP) separates cross‑cutting concerns such as logging, transactions, and security from core business logic, improving modularity, maintainability, and reusability, and the article explains its concepts, benefits, implementation methods (dynamic/static proxies, dedicated languages) and provides a Spring AOP code example.
This article explains how to design a plug‑in style architecture for data‑governance tasks by creating a custom URLClassLoader, dynamically loading JARs into a Spring context, registering and deregistering XXL‑Job handlers, updating configuration via YAML or Nacos, and finally unloading resources without restarting the service.
This article explains the problems of traditional session management in multi‑service environments, introduces session replication and centralized storage (using Redis), and demonstrates a complete CAS‑based single sign‑on solution with Java code examples for user, controller, filter, and configuration components.
This article demonstrates how to create a dynamically configurable thread pool in a Spring Boot backend by using Nacos as a configuration center, covering Maven dependencies, YAML configuration files, Nacos data IDs, Java implementation with listeners, a REST controller for testing, and practical verification steps.
This article walks through the practical application of Domain‑Driven Design to a large‑scale pricing system, detailing business understanding, strategic and tactical design, context integration, layered architecture, and concrete Java implementations that illustrate how DDD improves modularity, testability, and maintainability.
This guide demonstrates how to set up a Maven project with the Fabric8 Kubernetes Java client, configure minimal kubeconfig or ServiceAccount credentials, and use sample code to list namespaces, illustrating essential steps for connecting Java applications to a Kubernetes cluster with minimal configuration.
This article introduces Easy-Es, an ORM framework built on Elasticsearch's RestHighLevelClient, explains its architecture and advantages, and provides step‑by‑step instructions—including Maven/Gradle setup, configuration, entity and mapper creation, and full CRUD test examples—so developers can quickly integrate powerful search capabilities into Spring Boot applications.
This article examines why API requests fail, explains the importance of retry mechanisms, compares linear, exponential and randomized back‑off strategies, discusses maximum attempt considerations and idempotency, and provides a detailed Spring Boot implementation using Spring Retry along with alternative approaches.
This guide walks through setting up a Spring Boot project, adding Tess4J dependencies, configuring language data, implementing an OCR service class, exposing REST endpoints for local and remote image recognition, and testing the OCR functionality end‑to‑end.
This guide explains how Spring Security configuration changed after version 5.7, covering the shift from WebSecurityConfigurerAdapter to SecurityFilterChain beans, multiple filter chain setup, in‑memory user definitions, custom authorization decisions, and shared authentication components, with full code examples.
This article demonstrates how to build a hot‑pluggable AOP solution in Spring by dynamically adding and removing Advice at runtime, covering the required concepts, core implementation code, a complete demo, and practical considerations for backend Java developers.
Spring Boot, emerging as the preferred Java framework for microservices, differs from traditional Spring by offering automatic configuration, simplified Maven setup, embedded containers, production-ready features, and streamlined Spring MVC, which together accelerate development, ease deployment, and improve cloud integration compared to the more complex, slower-starting classic Spring.
Bloom filters are space‑efficient probabilistic structures that test set membership using multiple hash functions, offering fast, low‑memory checks with a controllable false‑positive rate, and can be implemented manually in Java, via Guava’s library, or deployed at scale with RedisBloom for distributed applications.
The article shows how to build a reliable Redis‑based distributed lock in a Spring Boot 2.7 application by storing a unique UUID token, acquiring the lock with SET NX PX, releasing it atomically via a Lua script, and providing a clean Lock interface, factory component, and JUnit example.
This article explains how to build a clean and maintainable Spring Boot controller layer by separating responsibilities, unifying response structures, applying comprehensive parameter validation (including custom rules), and implementing centralized exception handling to keep business logic concise and robust.
This article introduces Java 8 functional interfaces—including Function, Supplier, Consumer, and Runnable—explains their signatures, demonstrates how they can replace traditional if‑else statements for exception handling, branch processing, and null checks, and provides concrete code examples and usage tips.
This article explains how the LiteFlow rule engine can be used to design and execute serial, parallel, switch, and conditional business flows by defining components, EL rule files, data contexts, and configuration settings, and demonstrates its application with an e‑commerce order‑processing example.
This article explains the core concepts of Spring's @Autowired dependency injection, illustrates common mistakes such as unresolved circular dependencies and bean name collisions, and provides detailed solutions including constructor injection, qualifier usage, and bean priority annotations.
This article introduces the most useful Spring framework utility classes—including Assert, StringUtils, CollectionUtils, ObjectUtils, ClassUtils, BeanUtils, ReflectionUtils, Base64Utils, SerializationUtils, HttpStatus, and HtmlUtils—providing clear explanations, code examples, and practical tips to improve development efficiency and code quality.
This article explains how to implement multi‑rule rate limiting in a distributed Java application using Redis, covering String‑based counters, Zset timestamp storage, Lua scripts for atomic checks, custom @RateLimiter annotations, key generation logic, and an AOP interceptor that enforces the limits.
This article explains Java 8's lambda expressions and functional interfaces, demonstrates common functional interfaces with code examples, and shows how to use Stream API operations such as filter, map, flatMap, collect, max/min, count, reduce, and advanced collectors for efficient backend development.
This article explains how to use a MyBatis interceptor to cheaply improve database stability for high‑growth tables, compares common archiving and sharding solutions, and provides a complete, code‑driven implementation of date‑based horizontal sharding with binlog‑driven double‑write to handle critical‑point data continuity.
This article explains how to implement a robust distributed retry mechanism using message queues, annotations, and AOP, providing configurable options, visual monitoring, and code examples to help developers achieve eventual consistency with minimal boilerplate.
This article demonstrates how to implement small file uploads, large file chunked uploads, breakpoint resume, and instant upload using Spring Boot 3.1.2 on the backend and native JavaScript with spark‑md5 on the frontend, covering configuration, code examples, and practical considerations.
This guide explains how to import, configure, and apply the CheckStyle plugin in IntelliJ IDEA, covering common annotation, formatting, naming, logical, and import‑order issues, and provides step‑by‑step screenshots to help Java developers enforce coding standards efficiently.
This article explains the main Java JVM garbage collectors—including Serial, Parallel, CMS, G1, ZGC, Epsilon, and Shenandoah—detailing their architectures, pause characteristics, suitable workloads, and key advantages, helping developers choose the right collector for different application sizes and latency requirements.
This article explains why and how to replace OpenFeign with native Spring HttpInterface alternatives such as Apache HttpClient, OkHttp, and RestTemplate, covering security motivations, configuration details, code examples, and practical recommendations for microservice remote calls.
This article explains how to create a Spring Boot fat‑jar that externalizes its dependencies by configuring the spring‑boot‑maven‑plugin and maven‑assembly‑plugin to produce a ZIP layout, then uses the PropertiesLauncher with loader.path to load libraries from a separate libs directory at runtime.
This article explains how upgrading Java and Groovy dependencies caused an IllegalAccessException in Caffeine's asynchronous cache due to module encapsulation, and details the attempted fixes including JVM '--add-opens' arguments and dependency version adjustments.
This article explains how to protect Java server-side code from decompilation by applying ProGuard shrinking/obfuscation and Xjar/ClassFinal encryption, provides detailed Maven plugin configurations, sample pom.xml snippets, command‑line launch options, and demonstrates the resulting protected JARs with screenshots.
This article explains multiple backend optimization methods for Spring Boot, including asynchronous execution with @Async and CompletableFuture, increasing embedded Tomcat connection limits, using @ComponentScan, switching to Undertow, applying BufferedWriter, employing DeferredResult, and intercepting async calls with AsyncHandlerInterceptor, accompanied by concrete code examples.
This article explains Spring WebFlux's reactive programming model, compares it with Spring MVC, describes its concurrency advantages, and provides complete code examples for building a reactive Spring Boot application, helping developers decide when to adopt WebFlux.
This article explains the Nacos architecture, the principles of service registration, how Spring Cloud integrates with Nacos for automatic registration, the implementation details of NacosServiceRegistry, heartbeat mechanisms, registration via Open API/SDK, service address querying, and dynamic service discovery using HostReactor.
This article explains how to protect Java applications from decompilation by configuring a ProGuard file and adding the ProGuard Maven plugin, then building the project to generate an obfuscated JAR, complete with step‑by‑step instructions and sample configuration code.
This article explains how to control Spring bean initialization and destruction using interfaces and annotations, inject prototype beans into singleton controllers, implement various BeanPostProcessor extensions, dynamically register beans, use @Import, Runner interfaces, global exception handling, custom type conversion, BeanFactoryAware, web interceptors, and default AOP proxy creation.
This article explains why request debounce is essential for preventing duplicate submissions, outlines which APIs need protection, and walks through two distributed‑lock solutions—shared Redis cache and Redisson—showing concrete annotations, key‑generation logic, and Spring‑AOP code with full test results.
This article demonstrates how to implement API request throttling in a Spring Boot application using a custom Interceptor and Redis, covering basic principles, configuration, custom annotations, reflection for per‑endpoint limits, handling path parameters, and addressing timing logic nuances.
The author recounts a two‑year journey as a Java developer, describing experiences across three companies, the challenges of CRUD‑focused work, the need to learn front‑end skills, and insights on balancing technical growth with business understanding in both large and small firms.
This article introduces Easy-Es, an Elasticsearch ORM that mimics MyBatis‑Plus syntax, explains its key features, shows how to integrate it into a Spring Boot project, and provides comprehensive code examples for index management, CRUD, simple and advanced product searches, recommendation and aggregation functionalities.
This article explains why a naïve sequential export of hundreds of gigabytes of images from a database can take many hours, and demonstrates how adding indexes, using asynchronous processing, multithreading, and eliminating unnecessary decryption and local storage can reduce the runtime to minutes.
This article examines common scenarios that cause Spring transaction management to fail—such as non‑public methods, swallowed exceptions, incorrect rollback settings, self‑invocation, final methods, wrong propagation, asynchronous threads, unsupported database engines, and misuse of @Transactional—and provides concrete code‑level solutions to ensure reliable transactional behavior.
This tutorial demonstrates how to automate CRUD functionality in a Spring Boot application by introducing MyBatisPlus, creating a reusable utility class, configuring pagination, and implementing a generic BaseController that can be extended by concrete controllers for any entity.
This article demonstrates how to build a Spring‑based API rate‑limiting solution using an Interceptor and Redis, covering the basic principle, project setup, code implementation, custom annotation with reflection for flexible limits, handling path‑parameter keys, real‑IP acquisition, and practical considerations for production use.
This article explains the differences between CPU‑intensive and I/O‑intensive workloads, provides optimization strategies such as multithreading, caching, and load balancing, and presents Java code examples and formulas for calculating the optimal thread‑pool size based on core count, target CPU utilization, and blocking factors.
This article provides a comprehensive analysis of SpringBoot's run method, explaining its overall flow, the creation of SpringApplication objects, argument parsing, environment preparation, context refresh, and key extension points, while offering code examples to help developers understand the startup process.
This article explains how to implement a hot‑pluggable AOP mechanism in Spring by dynamically adding or removing Advice through custom endpoints and event listeners, covering core concepts, implementation code, a demonstration, and best‑practice considerations for backend developers.
This article explains how to efficiently insert massive amounts of data (over 100,000 rows) into a MySQL table by comparing plain JDBC single‑row inserts, JDBC batch inserts, MyBatis/MyBatis‑Plus foreach dynamic SQL, and the built‑in MyBatis‑Plus saveBatch method, while highlighting configuration tips and performance results.
This article demonstrates how to integrate Spring Expression Language (SpEL) with custom annotations and AOP in Spring Boot to create a highly flexible, maintainable permission‑checking mechanism that can handle various complex access scenarios without scattering hard‑coded logic throughout the codebase.
The article analyzes unexpected behaviors caused by PageHelper in a Java backend project—such as duplicate registrations, limited query results, and password update errors—by dissecting its source code, ThreadLocal usage, and the importance of proper startPage() and clearPage() handling.
Easy-Query is a Java ORM framework offering strong-typed, database-agnostic CRUD operations, complex SQL generation, multi-table joins, group awareness, and extensive function support, demonstrated through numerous code examples covering queries, joins, subqueries, pagination, and advanced features like enum handling and anonymous type alternatives.
This tutorial explains when to choose XML over JSON, compares their characteristics, and provides step‑by‑step Spring Boot 3.1.7 examples—including Jackson XML configuration, custom root elements, XML view rendering, and JAXB marshalling—to produce XML responses from REST endpoints.
This article presents the 20 most common Spring Boot interview questions, covering fundamentals, features, configuration, performance, security, microservices, and deployment, to help job seekers prepare effectively for Spring Boot related positions in the industry.
Easy-Es is a Java ORM framework built on Elasticsearch's RestHighLevelClient that simplifies search‑engine development, offers Mybatis‑Plus‑like usage, provides configuration and dependency details, and includes complete code examples for creating indexes and performing CRUD operations within Spring Boot applications.
This article explains Java 8's lambda expressions, functional interfaces, and the Stream API, demonstrating how immutable values and functions enable concise data processing through lazy and eager evaluation, with practical code examples covering predicates, consumers, mapping, filtering, grouping, and reduction.
This article provides a comprehensive overview of the major language and runtime enhancements introduced in JDK 12 through JDK 17, covering switch expressions, micro‑benchmarking with JMH, class‑data sharing, garbage‑collector improvements, new String methods, hidden and sealed classes, records, and unified asynchronous logging, all illustrated with code examples.
This article explains how to automate unit conversions for Java DTOs by first using a Map to mark fields and an enum for conversion types, then enhancing the solution with a custom annotation and reflection to make the process more reusable and maintainable.
This article introduces a curated collection of IntelliJ IDEA plugins—including Java Stream Debugger, JClassLib bytecode viewer, Maven Helper, JRebel, and many others—detailing their features, usage instructions, and benefits to enhance Java development productivity and code quality.
This article reviews six practical approaches for scheduling recurring jobs in Java—including custom threads, JDK ScheduledExecutorService, Spring @Scheduled, Quartz, Elastic‑Job, and XXL‑JOB—highlighting their usage, configuration steps, and considerations for clustering and concurrency.
This tutorial walks through creating a complete Spring Boot 2.7 project that integrates Apache Dubbo for RPC, covering environment setup, Maven dependency management, interface definition, provider and consumer implementations, configuration with Nacos, and testing the end‑to‑end service.
The article demonstrates replacing fragile if‑else channel logic with a Strategy pattern and Spring Expression Language, storing parameter mappings in a database so that new payment channels or Excel formats can be added simply by configuring SpEL expressions, achieving a flexible, maintainable, data‑driven solution.
Understanding asynchronous execution in Java can dramatically reduce latency for tasks such as sending SMS, emails, or updating data, and this article walks through eight practical implementations—from raw Threads and Futures to Spring @Async, ApplicationEvent, message queues, ThreadUtil, and Guava ListenableFuture—complete with code samples and best‑practice tips.
This article demonstrates a step‑by‑step method for exporting a list of unknown Java objects to an Excel/CSV file by leveraging reflection to dynamically generate headers and rows, complete with Maven dependencies, utility code, usage examples, and an extensible annotation‑based approach.
This tutorial explains why enterprise applications need multiple data sources, outlines the scenarios such as business isolation, migration, performance and maintainability, and provides a step‑by‑step implementation of dynamic data source routing in Spring Boot using custom context holders, routing classes, annotations, aspects, configuration, and web‑request control.
The article details how a high‑traffic Helios scoring service, originally taking several seconds to return a day’s worth of data, was profiled with Arthas and iteratively optimized through four code revisions, ultimately reducing latency to around 60 ms while exposing key performance pitfalls such as object creation, date formatting, and trivial list operations.
This article provides a comprehensive overview of Java annotations, covering their definition, common applications, classification into standard, meta, and custom annotations, detailed examples of built‑in annotations such as @Override, @Deprecated, @SuppressWarnings, and guidance on creating and using custom annotations with code snippets.
This article explains how to build a robust, thread‑safe local cache for Spring Boot applications by defining cache domain models, abstract managers, a centralized registry, and scheduled refresh tasks, while providing complete Java code examples and best‑practice recommendations.
This article explains how Spring Boot 3's Http Interface feature enables declarative HTTP service calls by defining Java interfaces, covering dependency setup, interface definition, token handling, configuration, controller integration, testing with Postman, and a brief discussion of its WebFlux dependency.
This article demonstrates how to replace heavyweight Spring Security with the lightweight Sa-Token framework by configuring token generation, session management, role and permission retrieval, and global gateway filters in a Spring Cloud micro‑service architecture, including complete code examples and deployment tips.
This article introduces the open‑source Disruptor framework, explains its ring‑buffer architecture, sequencer, wait‑strategy options, and provides complete Java code examples to demonstrate how to build high‑performance producer‑consumer pipelines without locks.
This guide walks through setting up Spring Authorization Server on Spring Boot 3.1 with JDK 17, covering environment setup, required dependencies, custom security filter chains, in‑memory user and client configurations, JWT signing, endpoint settings, consent service, and step‑by‑step testing of the authorization code flow.
This article walks through creating a standardized JSON response structure with a Result enum and wrapper class, demonstrates how to return it from controllers, implements a @ControllerAdvice‑based global exception handler with custom exceptions, and configures Logback for comprehensive logging in Spring Boot applications.
This article explains the limitations of traditional MVC, introduces the four‑layer DDD architecture (Interface, Application, Domain, Infrastructure), discusses the Dependency Inversion Principle, compares package‑level and Maven‑module implementations, and details the roles and conversions of Entity, DO, and DTO models for Java projects.
Switching from Java to Rust can shrink binaries from dozens of megabytes to a few kilobytes, cut memory use and latency dramatically, and provide safer, built‑in concurrency and async support, while Java remains attractive for its low learning curve and massive library ecosystem, prompting developers to wrap Rust crates for Java‑like productivity as they adopt Rust long‑term.
This article provides a comprehensive overview of the Java Virtual Machine, detailing its architecture, class loading process, runtime data areas, and execution engine, including interpreter and JIT compilation, to help readers grasp JVM fundamentals for Java development and interview preparation.
This article examines the design and implementation details of HikariCP—Spring Boot's default JDBC connection pool—explaining how its dual‑pool architecture, FastList collection, custom ConcurrentBag, bytecode‑level optimizations, and efficient connection acquisition and release mechanisms together deliver exceptional performance for Java backend applications.
This article explains Maven's version range syntax, illustrates how open-ended ranges like [2.3.0,) can cause unpredictable dependency versions and build failures, and offers practical solutions such as specifying exact versions or using dependencyManagement to ensure stable, reproducible builds.
This article walks through the common slow Excel‑to‑DB import pattern, shows why it becomes a bottleneck, and presents three progressive optimizations—including caching, asynchronous multi‑threaded reading, and double‑async processing—along with detailed Spring @Async thread‑pool configuration and EasyExcel alternatives, all illustrated with complete Java code samples.
This article explains Java's built‑in serialization drawbacks, introduces the open‑source ChronicleWire library as a high‑performance alternative supporting multiple data formats, and provides step‑by‑step code examples for encoding, decoding, and compatibility handling in real‑world Java applications.
This article introduces Java 8's lambda expressions, functional interfaces, and the Stream API, explaining key concepts such as lazy and eager evaluation, and demonstrates common stream operations like collect, filter, map, flatMap, max/min, count, and reduce with concrete code examples.
This article explains how to obtain a client’s IP address from an HttpServletRequest, convert it to a geographic location using the ip2region library, and provides multiple Java implementation options, Maven dependencies, and performance testing commands for efficient backend IP lookup.
This article demonstrates how to replace heavyweight Spring Security with the lightweight Sa-Token framework by configuring token generation, session storage in Redis, service discovery via Nacos, and permission checks in a Spring Cloud Gateway micro‑service architecture, complete with code examples and deployment settings.
This article explains how Java annotation processors work, why @Transactional requires rollbackFor=Exception.class to roll back checked exceptions, and provides a complete example of a custom processor using auto-service to enforce this Spring transaction configuration.
This article explains Spring’s event mechanism, covering its observer‑based design, benefits such as decoupling and asynchronous handling, standard framework events, and advanced generic event techniques using subclassing or ResolvableTypeProvider to achieve type‑safe, flexible event publishing.
This article provides a detailed explanation of Java’s parent delegation model, covering its definition, visual diagrams, advantages and disadvantages, and a six-step loading process, helping readers understand how class loaders prioritize parent loaders to ensure security and avoid duplicate class loading.
This article explains why upgrading from JDK8 or JDK11 to the long‑term support JDK17 brings significant garbage‑collector performance improvements, new language features, and better framework compatibility, and provides detailed migration steps, Maven and SpringBoot configuration changes, and troubleshooting tips.
Maven’s version ranges let you specify acceptable artifact versions, but open‑ended ranges like [2.3.0,) cause Maven to fetch the newest matching release, leading to nondeterministic builds and potential incompatibilities, so you should pin exact versions and use dependencyManagement for consistent, stable builds.
This article demonstrates how to store, create, update, and delete scheduled tasks in a SpringBoot application by leveraging ThreadPoolTaskScheduler, covering task configuration, utility classes, Cron expressions, and practical testing with full code examples.
This article demonstrates how to efficiently build department and regional hierarchical trees in Java by fetching all records in a single database query, using Stream API, Lambda expressions, in‑memory grouping, Redis caching and RocketMQ for asynchronous updates, achieving sub‑second response times even with tens of thousands of nodes.
Fury is a JIT‑compiled, zero‑copy, multi‑language serialization framework that delivers up to 170× speed improvements over traditional serializers, supports Java, Python, C++, Go, JavaScript, Scala and Rust, and has recently been donated to the Apache Software Foundation after a successful open‑source journey.
This article walks through the challenges of environment‑specific data isolation in a Java project, explains why adding an env column to every table is impractical, and presents a clean solution using a MyBatis interceptor that rewrites SQL and custom annotations to control filtering, ensuring safe, maintainable code across pre‑release, gray, and production environments.
This article explains why retry mechanisms are essential for unstable third‑party API calls, introduces Spring Retry, demonstrates how to configure synchronous and asynchronous retries, handle exception inclusion/exclusion, integrate circuit‑breaker fallback with Hystrix, and provides performance testing guidance, all with practical code examples.
