Added the JOL Examples

alimate · alimate · commit 5e619306249e · 2020-07-02T13:16:53.000+04:30
diff --git a/core-java-modules/core-java-jvm-2/src/test/java/com/baeldung/objectsize/Course.java b/core-java-modules/core-java-jvm-2/src/test/java/com/baeldung/objectsize/Course.java
@@ -0,0 +1,10 @@
+package com.baeldung.objectsize;
+
+public class Course {
+
+    private String name;
+
+    public Course(String name) {
+        this.name = name;
+    }
+}
diff --git a/core-java-modules/core-java-jvm-2/src/test/java/com/baeldung/objectsize/ObjectSizeUnitTest.java b/core-java-modules/core-java-jvm-2/src/test/java/com/baeldung/objectsize/ObjectSizeUnitTest.java
@@ -0,0 +1,40 @@
+package com.baeldung.objectsize;
+
+import org.junit.Test;
+import org.openjdk.jol.info.ClassLayout;
+import org.openjdk.jol.info.GraphLayout;
+import org.openjdk.jol.vm.VM;
+
+public class ObjectSizeUnitTest {
+
+    @Test
+    public void printingTheVMDetails() {
+        System.out.println(VM.current().details());
+    }
+
+    @Test
+    public void printingTheProfClassLayout() {
+        System.out.println(ClassLayout.parseClass(Professor.class).toPrintable());
+    }
+
+    @Test
+    public void printingTheCourseClassLayout() {
+        System.out.println(ClassLayout.parseClass(Course.class).toPrintable());
+    }
+
+    @Test
+    public void printingACourseInstanceLayout() {
+        String ds = "Data Structures";
+        Course course = new Course(ds);
+
+        System.out.println("The shallow size is :" + VM.current().sizeOf(course));
+
+        System.out.println(ClassLayout.parseInstance(course).toPrintable());
+        System.out.println(ClassLayout.parseInstance(ds).toPrintable());
+        System.out.println(ClassLayout.parseInstance(ds.toCharArray()).toPrintable());
+
+        System.out.println(GraphLayout.parseInstance(course).totalSize());
+        System.out.println(GraphLayout.parseInstance(course).toFootprint());
+        System.out.println(GraphLayout.parseInstance(course).toPrintable());
+    }
+}
diff --git a/core-java-modules/core-java-jvm-2/src/test/java/com/baeldung/objectsize/Professor.java b/core-java-modules/core-java-jvm-2/src/test/java/com/baeldung/objectsize/Professor.java
@@ -0,0 +1,25 @@
+package com.baeldung.objectsize;
+
+import java.time.LocalDate;
+import java.util.ArrayList;
+import java.util.List;
+
+public class Professor {
+
+    private String name;
+    private boolean tenured;
+    private List<Course> courses;
+    private int level;
+    private LocalDate birthDay;
+    private double lastEvaluation;
+
+    public Professor(String name, boolean tenured, List<Course> courses,
+      int level, LocalDate birthDay, double lastEvaluation) {
+        this.name = name;
+        this.tenured = tenured;
+        this.courses = courses;
+        this.level = level;
+        this.birthDay = birthDay;
+        this.lastEvaluation = lastEvaluation;
+    }
+}
