Add hashmap-vs-concurrenthashmap module: JDK 25 sizeCtl/treeify internals, forced and measured lost updates

Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_017ic4b7rnC7jppGGdHGESvy
2026-10-28 18:07:37 +00:00
parent 715036b640
commit f80e1079a8
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+<?xml version="1.0" encoding="UTF-8"?>
+<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>com.ankurm.interviewlab</groupId>
+  <artifactId>hashmap-vs-concurrenthashmap</artifactId>
+  <version>1.0.0</version>
+  <packaging>jar</packaging>
+
+  <name>java-interview-lab :: hashmap-vs-concurrenthashmap</name>
+  <description>
+    Runnable companion code for ankurm.com's "HashMap vs ConcurrentHashMap in Java" article:
+    reflective dumps of JDK 25 internals (sizeCtl, treeification), a forced-interleaving lost
+    update, a measured multi-thread lost-update run, and the computeIfAbsent recursion traps.
+  </description>
+
+  <properties>
+    <maven.compiler.release>25</maven.compiler.release>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <junit.version>6.1.3</junit.version>
+    <!-- Tests reflect into java.util.HashMap and java.util.concurrent.ConcurrentHashMap private
+         fields; JPMS refuses setAccessible(true) on them without these two flags. -->
+    <opens>--add-opens java.base/java.util=ALL-UNNAMED --add-opens java.base/java.util.concurrent=ALL-UNNAMED</opens>
+  </properties>
+
+  <dependencyManagement>
+    <dependencies>
+      <dependency>
+        <groupId>org.junit</groupId>
+        <artifactId>junit-bom</artifactId>
+        <version>${junit.version}</version>
+        <type>pom</type>
+        <scope>import</scope>
+      </dependency>
+    </dependencies>
+  </dependencyManagement>
+
+  <dependencies>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.platform</groupId>
+      <artifactId>junit-platform-launcher</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>3.6.0</version>
+        <configuration>
+          <argLine>${opens} -Xmx512m -Duser.timezone=UTC -Dfile.encoding=UTF-8</argLine>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>