Move the Memory Layout Codebase to a new Module

core-java-modules/core-java-jvm-2/README.md

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+## Core Java JVM Cookbooks and Examples
+
+This module contains articles about working with the Java Virtual Machine (JVM).
+
+### Relevant Articles: 

core-java-modules/core-java-jvm-2/pom.xml

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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>
+    <artifactId>core-java-jvm-2</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>core-java-jvm-2</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>${junit.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.openjdk.jol</groupId>
+            <artifactId>jol-core</artifactId>
+            <version>${jol-core.version}</version>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <assertj.version>3.6.1</assertj.version>
+        <jol-core.version>0.10</jol-core.version>
+    </properties>
+
+</project>

core-java-modules/core-java-jvm-2/src/test/java/com/baeldung/memlayout/MemoryLayoutUnitTest.java

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+package com.baeldung.memlayout;
+
+import org.junit.Test;
+import org.openjdk.jol.info.ClassLayout;
+import org.openjdk.jol.vm.VM;
+import sun.misc.Contended;
+
+public class MemoryLayoutUnitTest {
+
+    private volatile Object consumer;
+
+    @Test
+    public void printingTheVMDetails() {
+        System.out.println(VM.current().details());
+    }
+
+    @Test
+    public void simpleMemoryLayout() {
+        System.out.println(ClassLayout.parseClass(SimpleInt.class).toPrintable());
+    }
+
+    @Test
+    public void identityHashCodeMemoryLayout() {
+        SimpleInt instance = new SimpleInt();
+        System.out.println(ClassLayout.parseInstance(instance).toPrintable());
+
+        System.out.println("The identity hash code is " + System.identityHashCode(instance));
+        System.out.println(ClassLayout.parseInstance(instance).toPrintable());
+    }
+
+    @Test
+    public void alignmentMemoryLayout() {
+        System.out.println(ClassLayout.parseClass(SimpleLong.class).toPrintable());
+    }
+
+    @Test
+    public void fieldPackingMemoryLayout() {
+        System.out.println(ClassLayout.parseClass(FieldsArrangement.class).toPrintable());
+    }
+
+    @Test
+    public void monitorLockMemoryLayout() {
+        Lock lock = new Lock();
+        System.out.println(ClassLayout.parseInstance(lock).toPrintable());
+
+        synchronized (lock) {
+            System.out.println(ClassLayout.parseInstance(lock).toPrintable());
+        }
+    }
+
+    @Test
+    public void ageAndTenuringMemoryLayout() {
+        Object instance = new Object();
+        long lastAddr = VM.current().addressOf(instance);
+        ClassLayout layout = ClassLayout.parseInstance(instance);
+
+        for (int i = 0; i < 10_000; i++) {
+            long currentAddr = VM.current().addressOf(instance);
+            if (currentAddr != lastAddr) {
+                System.out.println(layout.toPrintable());
+            }
+
+            for (int j = 0; j < 10_000; j++) {
+                consumer = new Object();
+            }
+
+            lastAddr = currentAddr;
+        }
+    }
+
+    @Test
+    public void contendedMemoryLayout() {
+        System.out.println(ClassLayout.parseClass(Isolated.class).toPrintable());
+    }
+
+    @Test
+    public void arrayMemoryLayout() {
+        boolean[] booleans = new boolean[3];
+        System.out.println(ClassLayout.parseInstance(booleans).toPrintable());
+    }
+
+    private static class SimpleInt {
+        private int state;
+    }
+
+    private static class SimpleLong {
+        private long state;
+    }
+
+    private static class FieldsArrangement {
+        private boolean first;
+        private char second;
+        private double third;
+        private int forth;
+        private boolean fifth;
+    }
+
+    private static class Lock {}
+
+    private static class Isolated {
+
+        @Contended
+        private int i;
+
+        @Contended
+        private long l;
+    }
+}