《Java 并发编程·线程与内存模型》前言：环境、项目与读法

export JAVA_HOME=~/.jdks/jdk-25.0.5+8/Contents/Home
java -version          # 应输出 25.0.5
mvn -version           # 应输出 3.9.12

Apple M1 Pro，10 核，32 GB
macOS 26.3 (25D125)
Temurin 25.0.5+8
Maven 3.9.12

echo $JAVA_HOME
/usr/libexec/java_home -V

libraryd-conc/
├── pom.xml
├── conc-core/   src/main/java/com/plume/conc/core/   领域模型与 LoanService 实现
├── conc-lab/    src/main/java/com/plume/conc/lab/    JCStress、JMH、事故复现
└── conc-ops/    src/main/java/com/plume/conc/ops/    指标、诊断、压测脚本

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.plume.conc</groupId>
  <artifactId>libraryd-conc</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>pom</packaging>

  <modules>
    <module>conc-core</module>
    <module>conc-lab</module>
    <module>conc-ops</module>
  </modules>

  <properties>
    <maven.compiler.release>25</maven.compiler.release>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <junit.version>5.14.4</junit.version>
    <jcstress.version>0.16</jcstress.version>
    <jmh.version>1.37</jmh.version>
  </properties>
</project>

<dependencies>
  <dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter</artifactId>
    <version>${junit.version}</version>
    <scope>test</scope>
  </dependency>
</dependencies>

package com.plume.conc.core;

import java.time.Instant;
import java.util.Optional;

public record Book(String isbn, String title, int stock) {}

public record Member(String memberId, String name, int quota) {}

public record Loan(String loanId, String isbn, String memberId, Instant dueAt) {}

public record Reservation(String loanId, String isbn, String memberId, Instant dueAt) {}

public enum ErrorCode {
    BOOK_NOT_FOUND, OUT_OF_STOCK, QUOTA_EXCEEDED, CONFLICT, INTERRUPTED
}

public final class LoanException extends RuntimeException {
    private final ErrorCode code;

    public LoanException(ErrorCode code, String message) {
        super(message);
        this.code = code;
    }

    public ErrorCode code() {
        return code;
    }
}

public interface LoanService {
    Reservation reserve(String isbn, String memberId);
    boolean returnBook(String loanId);
}

public interface BookRepository {
    Optional<Book> findByIsbn(String isbn);
    void save(Book book);
}

public interface LoanRepository {
    Optional<Loan> findById(String loanId);
    void save(Loan loan);
}

package com.plume.conc.core;

import java.util.Optional;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

public final class InMemoryBookRepository implements BookRepository {
    private final ConcurrentMap<String, Book> books = new ConcurrentHashMap<>();

    public InMemoryBookRepository() {
        books.put("978-7-111-00001", new Book("978-7-111-00001", "并发编程实践", 100));
        books.put("978-7-111-00002", new Book("978-7-111-00002", "JVM 内核", 10));
    }

    @Override
    public Optional<Book> findByIsbn(String isbn) {
        return Optional.ofNullable(books.get(isbn));
    }

    @Override
    public void save(Book book) {
        books.put(book.isbn(), book);
    }
}

<dependencies>
  <dependency>
    <groupId>org.openjdk.jcstress</groupId>
    <artifactId>jcstress-core</artifactId>
    <version>${jcstress.version}</version>
  </dependency>
  <dependency>
    <groupId>org.openjdk.jmh</groupId>
    <artifactId>jmh-core</artifactId>
    <version>${jmh.version}</version>
  </dependency>
  <dependency>
    <groupId>org.openjdk.jmh</groupId>
    <artifactId>jmh-generator-annprocess</artifactId>
    <version>${jmh.version}</version>
    <scope>provided</scope>
  </dependency>
</dependencies>

<build>
  <plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-compiler-plugin</artifactId>
      <version>3.13.0</version>
      <configuration>
        <annotationProcessorPaths>
          <path>
            <groupId>org.openjdk.jcstress</groupId>
            <artifactId>jcstress-core</artifactId>
            <version>${jcstress.version}</version>
          </path>
          <path>
            <groupId>org.openjdk.jmh</groupId>
            <artifactId>jmh-generator-annprocess</artifactId>
            <version>${jmh.version}</version>
          </path>
        </annotationProcessorPaths>
      </configuration>
    </plugin>
  </plugins>
</build>

Exception in thread "main" java.lang.NullPointerException
	at java.base/java.io.Reader.<init>(Reader.java:286)
	at org.openjdk.jcstress.infra.runners.TestList.getTests(TestList.java:51)

mvn -q package -DskipTests
java -jar conc-lab/target/conc-lab-1.0-SNAPSHOT.jar -t LostUpdate -m quick

----- [N/A] Checking for biased locking support
Unrecognized VM option 'UseBiasedLocking'

java -cp conc-lab/target/conc-lab-1.0-SNAPSHOT.jar org.openjdk.jmh.Main LongAdderBench

java -XX:StartFlightRecording=filename=app.jfr,duration=30s -cp target/classes com.plume.conc.core.Main
jfr print --events jdk.VirtualThreadPinned app.jfr
jfr summary app.jfr

jcmd <pid> Thread.print
jcmd <pid> Thread.print -l      # 同时打印锁信息

mvn -q compile -Dmaven.compiler.enablePreview=true
java --enable-preview -cp target/classes com.plume.conc.core.StructuredDemo