Focus on Java-related technologies: SSM, Spring ecosystem, microservices, MySQL, MyCat, clustering, distributed systems, middleware, Linux, networking, multithreading. Occasionally cover DevOps tools like Jenkins, Nexus, Docker, and ELK. Also share technical insights from time to time, committed to Java full-stack development!
This article explains how Lombok’s automatic getter/setter generation can cause MyBatis to store enum fields as null, details the underlying JavaBeans naming conflict, and also reveals why EasyExcel fails with @Accessor(chain=true) annotations, offering practical solutions for both problems.
The article examines Meituan’s pioneering use of AI interviewers and the NoCode product, explains the emerging “Vibe Coding” approach, and argues that future software engineering interviews should assess candidates’ ability to collaborate with AI tools rather than merely memorizing algorithms.
This article explains how Java's BigDecimal class maintains exact decimal precision by scaling numbers to integers, detailing its internal fields, the add method implementation, and a concrete example that demonstrates the underlying computation steps.
This article explains how to handle JSON objects with unknown or dynamic fields in Java using Jackson's @JsonAnySetter to collect extra properties into a Map and @JsonAnyGetter to serialize them back as regular fields, complete with practical code examples and common pitfalls.
The article explains why using the vague term “user” in software design creates hidden security flaws, illustrates the problem with examples from ticket booking, Unix, and SaaS systems, and urges early terminology planning to avoid costly redesigns.
This guide explains how to load external JAR files into the JVM, configure SpringBoot to recognize them, and choose among several class‑loading strategies—including expanding the classpath, using the loader.path parameter, or implementing a custom classloader—while providing Maven configuration examples and code snippets.
This article reveals how SpringBoot's out‑of‑the‑box defaults—such as Tomcat connection limits, HikariCP pool size, JPA lazy loading, Jackson timezone handling, logging, file upload limits, async thread pools, static resource caching, and transaction timeouts—can cause performance bottlenecks and stability issues in production, and provides concrete configuration recommendations to prevent them.
This article walks through eight practical MySQL optimization techniques—including smarter LIMIT usage, avoiding implicit type conversion, rewriting UPDATE/DELETE with JOINs, handling mixed sorting, replacing EXISTS with joins, pushing predicates, narrowing result sets early, and leveraging WITH clauses—to dramatically reduce query execution time from seconds to milliseconds.
This article explains how to implement an online‑user counting feature using Redis sorted sets (zset) by leveraging the four core commands zadd, zrangeByScore, zremrangeByScore, and zrem, with Java/Spring code examples and optional browser‑fingerprinting for unauthenticated visitors.
This guide explains why traditional Java apps require restarts for config changes, introduces Spring Boot's @RefreshScope for hot configuration updates, details its core principles, provides step‑by‑step implementation, best practices, troubleshooting tips, and advanced use cases such as dynamic feature toggles and logging level adjustments.
