Added the Java Agent Example

alimate · alimate · commit 87a1af06beb6 · 2020-07-02T14:26:40.000+04:30
diff --git a/core-java-modules/core-java-jvm-2/src/test/java/com/baeldung/objectsize/InstrumentedSize.java b/core-java-modules/core-java-jvm-2/src/test/java/com/baeldung/objectsize/InstrumentedSize.java
@@ -0,0 +1,11 @@
+package com.baeldung.objectsize;
+
+public class InstrumentedSize {
+
+    public static void main(String[] args) {
+        String ds = "Data Structures";
+        Course course = new Course(ds);
+
+        System.out.println(ObjectSizeCalculator.sizeOf(course));
+    }
+}
diff --git a/core-java-modules/core-java-jvm-2/src/test/java/com/baeldung/objectsize/MANIFEST.MF b/core-java-modules/core-java-jvm-2/src/test/java/com/baeldung/objectsize/MANIFEST.MF
@@ -0,0 +1 @@
+Premain-Class: com.baeldung.objectsize.ObjectSizeCalculator
diff --git a/core-java-modules/core-java-jvm-2/src/test/java/com/baeldung/objectsize/ObjectSizeCalculator.java b/core-java-modules/core-java-jvm-2/src/test/java/com/baeldung/objectsize/ObjectSizeCalculator.java
@@ -0,0 +1,16 @@
+package com.baeldung.objectsize;
+
+import java.lang.instrument.Instrumentation;
+
+public class ObjectSizeCalculator {
+
+    private static Instrumentation instrumentation;
+
+    public static void premain(String args, Instrumentation inst) {
+        instrumentation = inst;
+    }
+
+    public static long sizeOf(Object o) {
+        return instrumentation.getObjectSize(o);
+    }
+}

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+Premain-Class: com.baeldung.objectsize.ObjectSizeCalculator`