Advanced Java 示例项目

本项目包含了一系列Java高级特性的示例代码，主要涉及Java Agent技术、多线程编程、IO操作等。

项目结构

src/
├── main/
│   └── java/
│       └── com/
│           └── zhouwy/
│               └── advancedjava/
│                   ├── agent/                     # Java Agent 相关类
│                   │   └── MethodAgentMain.java   # Agent 主类
│                   ├── concurrency/               # 并发编程相关类
│                   │   ├── lock/
│                   │   │   ├── ConditionTest.java
│                   │   │   └── RenentrantLockTest.java
│                   │   ├── forkjoin/
│                   │   │   └── forkJoin.java
│                   │   └── thread/
│                   │       ├── ThreadApp.java
│                   │       └── ThreadsInterrupt.java
│                   ├── io/                        # IO操作相关类
│                   │   ├── file/
│                   │   │   ├── CharByte.java
│                   │   │   ├── FileUtils.java
│                   │   │   └── RandAccessFileTests.java
│                   │   └── IOTests.java
│                   ├── interview/                 # 面试题示例
│                   │   ├── records/
│                   │   │   ├── CandidateProfile.java
│                   │   │   ├── CandidateProfileClassic.java
│                   │   │   ├── InterviewResult.java
│                   │   │   ├── InterviewResultClassic.java
│                   │   │   └── RecordDemoApp.java
│                   │   ├── serialization/
│                   │   │   ├── CandidatePayloadRecord.java
│                   │   │   ├── CandidatePayloadClassic.java
│                   │   │   └── JsonSerializationDemoApp.java
│                   │   ├── concurrency/
│                   │   │   ├── ConcurrencyFeatureShowcaseApp.java
│                   │   │   ├── ThreadPoolTuningDemo.java
│                   │   │   ├── CompletableFutureOrchestrationDemo.java
│                   │   │   ├── SemaphoreBulkheadDemo.java
│                   │   │   ├── CountDownLatchBatchDemo.java
│                   │   │   ├── LongAdderVsAtomicLongDemo.java
│                   │   │   ├── StampedLockOptimisticReadDemo.java
│                   │   │   ├── AqsCustomMutexDemo.java
│                   │   │   ├── LockSupportHandshakeDemo.java
│                   │   │   ├── ConcurrentSkipListMapRankingDemo.java
│                   │   │   ├── CopyOnWriteArrayListReadMostlyDemo.java
│                   │   │   ├── ConcurrentHashMapComputeDemo.java
│                   │   │   └── CyclicBarrierPhaserDemo.java
│                   │   └── frameworks/
│                   │       ├── spring/
│                   │       │   ├── InterviewAiProperties.java
│                   │       │   ├── InterviewAiConfig.java
│                   │       │   └── InterviewRecordController.java
│                   │       ├── springdata/
│                   │       │   ├── InterviewResultEntity.java
│                   │       │   ├── InterviewSummary.java
│                   │       │   └── InterviewResultRepository.java
│                   │       └── jdk/
│                   │           └── RecordIntrospectionDemo.java
│                   └── demo/                      # 示例程序
│                       ├── AgentTest.java         # Agent 测试类
│                       └── AttachMain.java        # Attach 示例类

核心功能

1. Java Agent 技术

项目演示了Java Agent的两种使用方式：

静态加载（Premain）

在JVM启动时通过命令行参数加载Agent
MethodAgentMain.java 实现了premain方法
可以在类加载时对字节码进行修改

动态加载（Agentmain）

在JVM运行时动态加载Agent
MethodAgentMain.java 实现了agentmain方法
使用Javassist库对目标类的方法进行增强

2. 多线程编程示例

包含了多个关于Java并发编程的示例：

ConditionTest.java - Condition条件变量使用示例
RenentrantLockTest.java - 可重入锁使用示例
ThreadsInterrupt.java - 线程中断处理示例
forkJoin.java - Fork/Join框架使用示例

3. IO操作示例

提供了各种IO操作的示例代码：

CharByte.java - 字符与字节流操作示例
FileUtils.java - 文件工具类示例
RandAccessFileTests.java - 随机访问文件示例
IOTests.java - 基础IO操作示例

4. Java Record 面试示例

新增了 record 的面试高频用法示例：

CandidateProfile.java - 紧凑构造器校验、重载构造器、防御性拷贝
CandidateProfileClassic.java - 传统POJO等价实现（字段/getter/equals/hashCode/toString 手写）
InterviewResult.java - 组合record、静态工厂方法、参数归一化
InterviewResultClassic.java - 传统POJO等价实现（便于与record对照）
RecordDemoApp.java - 访问器、值相等、toString 示例
CandidateProfileTest.java - 单元测试覆盖核心行为

对照重点：

record 访问器是 name()，传统POJO通常是 getName()
record 自动生成 equals/hashCode/toString，传统POJO需要手写
record 同样可以写构造器校验和业务方法，不只是“裸字段”

5. Jackson/Fastjson2 序列化示例

新增了 record + 传统POJO 在两种 JSON 工具下的对照示例：

CandidatePayloadRecord.java - record + 旧字段别名兼容（years -> yearsOfExperience）
CandidatePayloadClassic.java - 传统POJO写法对照
JsonSerializationDemoApp.java - Jackson/Fastjson2 序列化与反序列化演示
JsonSerializationExamplesTest.java - 兼容性与往返测试

6. 主流框架 Record 用法示例

新增了 Spring Boot / Spring Web / Spring Data JPA / JDK 的 record 代码示例：

InterviewAiProperties.java - @ConfigurationProperties + record 配置绑定
InterviewRecordController.java - Spring Web 请求/响应 DTO 使用 record
InterviewResultRepository.java - JPA 用 record 做查询投影（constructor expression）
RecordIntrospectionDemo.java - JDK 反射 API 读取 record 元数据
RecordIntrospectionDemoTest.java - JDK record 反射测试

7. 并发高级功能点小 Demo

新增了可直接运行的并发小实验（均带中文注释）：

ConcurrencyFeatureShowcaseApp.java - 串联入口，一次跑完全部 demo
ThreadPoolTuningDemo.java - 线程池参数与拒绝策略（CallerRuns 背压）
CompletableFutureOrchestrationDemo.java - 并行编排、超时与兜底
SemaphoreBulkheadDemo.java - Semaphore 限流/舱壁
CountDownLatchBatchDemo.java - 批任务汇聚
LongAdderVsAtomicLongDemo.java - 高竞争计数对比
StampedLockOptimisticReadDemo.java - 乐观读 + 回退悲观读
AqsCustomMutexDemo.java - AQS 自定义同步器（不可重入互斥锁）
LockSupportHandshakeDemo.java - LockSupport 线程握手
ConcurrentSkipListMapRankingDemo.java - 跳表有序并发容器
CopyOnWriteArrayListReadMostlyDemo.java - 读多写少容器
ConcurrentHashMapComputeDemo.java - compute 原子更新防超卖
CyclicBarrierPhaserDemo.java - 多阶段协作
CONCURRENCY_STUDY_MAP.md - 并发高级知识总图（已覆盖/待进阶）

构建和运行

项目使用Maven进行构建管理，需要Java 17环境。

编译打包

mvn clean package

该命令会生成两个jar包：

advancedJava-1.0-SNAPSHOT.jar - 普通jar包
advancedJava-1.0-SNAPSHOT-jar-with-dependencies.jar - 包含所有依赖的uber-jar

运行示例

运行Agent测试程序

首先运行目标应用程序：

java -cp target/advancedJava-1.0-SNAPSHOT.jar com.advancedjava.demo.AgentTest

然后在另一个终端中运行Attach程序来动态加载Agent：

java -cp target/advancedJava-1.0-SNAPSHOT-jar-with-dependencies.jar com.advancedjava.demo.AttachMain

静态加载Agent方式

java -javaagent:target/advancedJava-1.0-SNAPSHOT-jar-with-dependencies.jar -cp target/advancedJava-1.0-SNAPSHOT.jar com.advancedjava.demo.AgentTest

运行 Record 示例

mkdir -p /tmp/record-demo-classes
javac -d /tmp/record-demo-classes \
  src/main/java/com/advancedjava/interview/records/CandidateProfile.java \
  src/main/java/com/advancedjava/interview/records/CandidateProfileClassic.java \
  src/main/java/com/advancedjava/interview/records/InterviewResult.java \
  src/main/java/com/advancedjava/interview/records/InterviewResultClassic.java \
  src/main/java/com/advancedjava/interview/records/RecordDemoApp.java
java -cp /tmp/record-demo-classes com.advancedjava.interview.records.RecordDemoApp

运行 Record 单元测试

mkdir -p /tmp/record-test-classes
javac -d /tmp/record-test-classes \
  -cp "$HOME/.m2/repository/junit/junit/4.13.1/junit-4.13.1.jar:$HOME/.m2/repository/org/hamcrest/hamcrest/2.2/hamcrest-2.2.jar" \
  src/main/java/com/advancedjava/interview/records/CandidateProfile.java \
  src/main/java/com/advancedjava/interview/records/CandidateProfileClassic.java \
  src/main/java/com/advancedjava/interview/records/InterviewResult.java \
  src/main/java/com/advancedjava/interview/records/InterviewResultClassic.java \
  src/test/java/com/advancedjava/interview/records/CandidateProfileTest.java
java -cp "/tmp/record-test-classes:$HOME/.m2/repository/junit/junit/4.13.1/junit-4.13.1.jar:$HOME/.m2/repository/org/hamcrest/hamcrest/2.2/hamcrest-2.2.jar" \
  org.junit.runner.JUnitCore com.advancedjava.interview.records.CandidateProfileTest

运行 Jackson/Fastjson2 示例

mkdir -p /tmp/serialization-demo-classes
javac -d /tmp/serialization-demo-classes \
  -cp "$HOME/.m2/repository/com/alibaba/fastjson2/fastjson2/2.0.60/fastjson2-2.0.60.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.17.1/jackson-databind-2.17.1.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.17.1/jackson-core-2.17.1.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.17.1/jackson-annotations-2.17.1.jar" \
  src/main/java/com/advancedjava/interview/serialization/CandidatePayloadRecord.java \
  src/main/java/com/advancedjava/interview/serialization/CandidatePayloadClassic.java \
  src/main/java/com/advancedjava/interview/serialization/JsonSerializationDemoApp.java
java -cp "/tmp/serialization-demo-classes:$HOME/.m2/repository/com/alibaba/fastjson2/fastjson2/2.0.60/fastjson2-2.0.60.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.17.1/jackson-databind-2.17.1.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.17.1/jackson-core-2.17.1.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.17.1/jackson-annotations-2.17.1.jar" \
  com.advancedjava.interview.serialization.JsonSerializationDemoApp

运行 Jackson/Fastjson2 测试

mkdir -p /tmp/serialization-test-classes
javac -d /tmp/serialization-test-classes \
  -cp "$HOME/.m2/repository/junit/junit/4.13.1/junit-4.13.1.jar:$HOME/.m2/repository/org/hamcrest/hamcrest/2.2/hamcrest-2.2.jar:$HOME/.m2/repository/com/alibaba/fastjson2/fastjson2/2.0.60/fastjson2-2.0.60.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.17.1/jackson-databind-2.17.1.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.17.1/jackson-core-2.17.1.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.17.1/jackson-annotations-2.17.1.jar" \
  src/main/java/com/advancedjava/interview/serialization/CandidatePayloadRecord.java \
  src/main/java/com/advancedjava/interview/serialization/CandidatePayloadClassic.java \
  src/test/java/com/advancedjava/interview/serialization/JsonSerializationExamplesTest.java
java -cp "/tmp/serialization-test-classes:$HOME/.m2/repository/junit/junit/4.13.1/junit-4.13.1.jar:$HOME/.m2/repository/org/hamcrest/hamcrest/2.2/hamcrest-2.2.jar:$HOME/.m2/repository/com/alibaba/fastjson2/fastjson2/2.0.60/fastjson2-2.0.60.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.17.1/jackson-databind-2.17.1.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.17.1/jackson-core-2.17.1.jar:$HOME/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.17.1/jackson-annotations-2.17.1.jar" \
  org.junit.runner.JUnitCore com.advancedjava.interview.serialization.JsonSerializationExamplesTest

运行 JDK Record 反射示例

mkdir -p /tmp/framework-jdk-demo-classes
javac -d /tmp/framework-jdk-demo-classes \
  src/main/java/com/advancedjava/interview/frameworks/jdk/RecordIntrospectionDemo.java
java -cp /tmp/framework-jdk-demo-classes \
  com.advancedjava.interview.frameworks.jdk.RecordIntrospectionDemo

运行 JDK Record 反射测试

mkdir -p /tmp/framework-jdk-test-classes
javac -d /tmp/framework-jdk-test-classes \
  -cp "$HOME/.m2/repository/junit/junit/4.13.1/junit-4.13.1.jar:$HOME/.m2/repository/org/hamcrest/hamcrest/2.2/hamcrest-2.2.jar" \
  src/main/java/com/advancedjava/interview/frameworks/jdk/RecordIntrospectionDemo.java \
  src/test/java/com/advancedjava/interview/frameworks/jdk/RecordIntrospectionDemoTest.java
java -cp "/tmp/framework-jdk-test-classes:$HOME/.m2/repository/junit/junit/4.13.1/junit-4.13.1.jar:$HOME/.m2/repository/org/hamcrest/hamcrest/2.2/hamcrest-2.2.jar" \
  org.junit.runner.JUnitCore com.advancedjava.interview.frameworks.jdk.RecordIntrospectionDemoTest

运行并发功能点串联 Demo

mkdir -p /tmp/concurrency-demo-classes
javac -d /tmp/concurrency-demo-classes \
  src/main/java/com/advancedjava/interview/concurrency/*.java
java -cp /tmp/concurrency-demo-classes \
  com.advancedjava.interview.concurrency.ConcurrencyFeatureShowcaseApp

依赖项

Javassist 3.25.0-GA - 字节码操作库
JUnit 4.13.1 - 单元测试框架
JDK Tools - JVM工具类（用于动态attach到JVM进程）

注意事项

项目使用Java 17编译，需要相应版本的JDK才能正常运行
动态Attach功能需要相应的权限设置
在不同操作系统上运行时可能需要调整部分系统相关的代码

Name		Name	Last commit message	Last commit date
Latest commit History 26 Commits
.agents/skills/opencli-rs		.agents/skills/opencli-rs
.settings		.settings
docs/superpowers		docs/superpowers
src		src
.classpath		.classpath
.gitignore		.gitignore
.project		.project
AGENTS.md		AGENTS.md
CONCURRENCY_STUDY_MAP.md		CONCURRENCY_STUDY_MAP.md
README.md		README.md
pom.xml		pom.xml
skills-lock.json		skills-lock.json
todoList.md		todoList.md

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Repository files navigation

Advanced Java 示例项目

项目结构

核心功能

1. Java Agent 技术

静态加载（Premain）

动态加载（Agentmain）

2. 多线程编程示例

3. IO操作示例

4. Java Record 面试示例

5. Jackson/Fastjson2 序列化示例

6. 主流框架 Record 用法示例

7. 并发高级功能点小 Demo

构建和运行

编译打包

运行示例

运行Agent测试程序

静态加载Agent方式

运行 Record 示例

运行 Record 单元测试

运行 Jackson/Fastjson2 示例

运行 Jackson/Fastjson2 测试

运行 JDK Record 反射示例

运行 JDK Record 反射测试

运行并发功能点串联 Demo

依赖项

注意事项

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Repository files navigation

Advanced Java 示例项目

项目结构

核心功能

1. Java Agent 技术

静态加载（Premain）

动态加载（Agentmain）

2. 多线程编程示例

3. IO操作示例

4. Java Record 面试示例

5. Jackson/Fastjson2 序列化示例

6. 主流框架 Record 用法示例

7. 并发高级功能点小 Demo

构建和运行

编译打包

运行示例

运行Agent测试程序

静态加载Agent方式

运行 Record 示例

运行 Record 单元测试

运行 Jackson/Fastjson2 示例

运行 Jackson/Fastjson2 测试

运行 JDK Record 反射示例

运行 JDK Record 反射测试

运行并发功能点串联 Demo

依赖项

注意事项

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