三个缓存全部是Spring核心注册表的成员变量，存储结构都是HashMap，各自职责绝对隔离，不存在功能重叠。 做后端开发，几乎 ...

上周帮一个学弟做模拟面试。他准备了三个月，把网上能找到的Java面试题背了个遍。从HashMap扩容到线程池参数，从JVM垃圾回收到MySQL隔离级别，倒背如流。 我随便问了一句：“你们线上系统用过线程池吗？corePoolSize和maxPoolSize你是怎么设置的？” 他愣了三秒 ...

ConcurrentHashMap从JDK1.7到JDK1.8，底层实现发生了翻天覆地的变化。**Segment分段锁被彻底抛弃，改用CAS+synchronized，锁粒度从"段"细化到了"桶"**。这个变化，直接决定了面试的成败。 一、面试场景引入 上周一个朋友去阿里面试，回来跟我吐槽："面试官问我 ...

Java dominates the backend development, which supports everything from enterprise systems to cloud-native applications. With the advent of microservices and cloud-based solutions as well as increased ...

我在之前两讲介绍了Java集合框架的典型容器类，它们绝大部分都不是线程安全的，仅有的线程安全实现，比如Vector、Stack，在性能方面也远不尽如人意。幸好Java语言提供了并发包（java.util.concurrent），为高度并发需求提供了更加全面的工具支持。 今天我要问你的 ...

KSafe ships KSAFE_SKILL.md — an agentskills.io-compatible skill that teaches any AI agent (Claude Code, Codex, Gemini CLI, Copilot CLI, Junie) KSafe's patterns, anti-patterns, and gotchas. Restart ...

Have you ever wondered how Java seamlessly combines its primitive data types with object-oriented programming? Enter wrapper classes, an important but often overlooked Java feature. These special ...

Iterators in Java typically expect exclusive access to the data structure they loop through. If another thread tries to modify a collection of objects while an ...