diff --git a/core-java/src/main/java/com/baeldung/keyword/Circle.java b/core-java/src/main/java/com/baeldung/keyword/Circle.java
new file mode 100644
index 0000000000..231b2f5a59
--- /dev/null
+++ b/core-java/src/main/java/com/baeldung/keyword/Circle.java
@@ -0,0 +1,5 @@
+package com.baeldung.keyword;
+
+public class Circle extends Round implements Shape {
+
+}
diff --git a/core-java/src/main/java/com/baeldung/keyword/Ring.java b/core-java/src/main/java/com/baeldung/keyword/Ring.java
new file mode 100644
index 0000000000..99873f9640
--- /dev/null
+++ b/core-java/src/main/java/com/baeldung/keyword/Ring.java
@@ -0,0 +1,4 @@
+package com.baeldung.keyword;
+
+public class Ring extends Round {
+}
diff --git a/core-java/src/main/java/com/baeldung/keyword/Round.java b/core-java/src/main/java/com/baeldung/keyword/Round.java
new file mode 100644
index 0000000000..0e2cc2c8c7
--- /dev/null
+++ b/core-java/src/main/java/com/baeldung/keyword/Round.java
@@ -0,0 +1,4 @@
+package com.baeldung.keyword;
+
+public class Round {
+}
diff --git a/core-java/src/main/java/com/baeldung/keyword/Shape.java b/core-java/src/main/java/com/baeldung/keyword/Shape.java
new file mode 100644
index 0000000000..8d00c165a3
--- /dev/null
+++ b/core-java/src/main/java/com/baeldung/keyword/Shape.java
@@ -0,0 +1,4 @@
+package com.baeldung.keyword;
+
+public interface Shape {
+}
diff --git a/core-java/src/main/java/com/baeldung/keyword/Triangle.java b/core-java/src/main/java/com/baeldung/keyword/Triangle.java
new file mode 100644
index 0000000000..406b8f23e5
--- /dev/null
+++ b/core-java/src/main/java/com/baeldung/keyword/Triangle.java
@@ -0,0 +1,4 @@
+package com.baeldung.keyword;
+
+public class Triangle implements Shape {
+}
diff --git a/core-java/src/test/java/com/baeldung/keyword/test/InstanceOfUnitTest.java b/core-java/src/test/java/com/baeldung/keyword/test/InstanceOfUnitTest.java
new file mode 100644
index 0000000000..4c010e3a16
--- /dev/null
+++ b/core-java/src/test/java/com/baeldung/keyword/test/InstanceOfUnitTest.java
@@ -0,0 +1,55 @@
+package com.baeldung.keyword.test;
+
+import org.junit.Assert;
+import org.junit.jupiter.api.Test;
+
+import com.baeldung.keyword.Circle;
+import com.baeldung.keyword.Ring;
+import com.baeldung.keyword.Round;
+import com.baeldung.keyword.Shape;
+import com.baeldung.keyword.Triangle;
+
+public class InstanceOfUnitTest {
+
+    @Test
+    public void giveWhenInstanceIsCorrect_thenReturnTrue() {
+        Ring ring = new Ring();
+        Assert.assertTrue("ring is instance of Round ", ring instanceof Round);
+    }
+
+    @Test
+    public void giveWhenObjectIsInstanceOfType_thenReturnTrue() {
+        Circle circle = new Circle();
+        Assert.assertTrue("circle is instance of Circle ", circle instanceof Circle);
+    }
+
+  
+    @Test
+    public void giveWhenInstanceIsOfSubtype_thenReturnTrue() {
+        Circle circle = new Circle();
+        Assert.assertTrue("circle is instance of Round", circle instanceof Round);
+    }
+
+    @Test
+    public void giveWhenTypeIsInterface_thenReturnTrue() {
+        Circle circle = new Circle();
+        Assert.assertTrue("circle is instance of Shape", circle instanceof Shape);
+    }
+    
+    @Test
+    public void giveWhenTypeIsOfObjectType_thenReturnTrue() {
+        Thread thread = new Thread();
+        Assert.assertTrue("thread is instance of Object", thread instanceof Object);
+    }
+
+    @Test
+    public void giveWhenInstanceValueIsNull_thenReturnFalse() {
+        Circle circle = null;
+        Assert.assertFalse("circle is instance of Round", circle instanceof Round);
+    }
+
+    @Test
+    public void giveWhenComparingClassInDiffHierarchy_thenCompilationError() {
+        // Assert.assertFalse("circle is instance of Triangle", circle instanceof Triangle);
+    }
+}