immutable: List.of vs unmodifiableList vs copyOf - null handling, views vs copies, JMH wrap/copy overhead, a Guava comparison, and the record defensive-copy trap

2026-10-01 11:32:13 +00:00
parent 64de44fa65
commit 2eaa464bad
18 changed files with 731 additions and 0 deletions
@@ -0,0 +1,89 @@
+<?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>
+
+  <parent>
+    <groupId>com.ankurm</groupId>
+    <artifactId>java-core-examples</artifactId>
+    <version>1.0</version>
+  </parent>
+
+  <artifactId>immutable</artifactId>
+  <name>immutable</name>
+  <description>List.of/Map.of vs Collections.unmodifiableList vs List.copyOf: null handling, views vs copies, JMH overhead, a brief Guava comparison, and defensive copies in records.</description>
+
+  <properties>
+    <jmh.version>1.37</jmh.version>
+    <guava.version>33.7.2-jre</guava.version>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava</artifactId>
+      <version>${guava.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>org.openjdk.jmh</groupId>
+      <artifactId>jmh-core</artifactId>
+      <version>${jmh.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>org.openjdk.jmh</groupId>
+      <artifactId>jmh-generator-annprocess</artifactId>
+      <version>${jmh.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter</artifactId>
+      <version>5.11.0</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <finalName>benchmarks</finalName>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <version>3.13.0</version>
+        <configuration>
+          <release>25</release>
+          <annotationProcessorPaths>
+            <path>
+              <groupId>org.openjdk.jmh</groupId>
+              <artifactId>jmh-generator-annprocess</artifactId>
+              <version>${jmh.version}</version>
+            </path>
+          </annotationProcessorPaths>
+        </configuration>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>3.2.5</version>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-shade-plugin</artifactId>
+        <version>3.5.1</version>
+        <executions>
+          <execution>
+            <phase>package</phase>
+            <goals><goal>shade</goal></goals>
+            <configuration>
+              <transformers>
+                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                  <mainClass>org.openjdk.jmh.Main</mainClass>
+                </transformer>
+              </transformers>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>