diff --git a/MoreOnClasses/src/main/java/com/oop/ElVehicle.java b/MoreOnClasses/src/main/java/com/oop/ElVehicle.java
new file mode 100644
index 0000000..fa040f3
--- /dev/null
+++ b/MoreOnClasses/src/main/java/com/oop/ElVehicle.java
@@ -0,0 +1,7 @@
+package com.oop;
+
+public class ElVehicle extends Vehicle {
+    public void resource(){
+        System.out.println("I use electricity");
+    }
+}
diff --git a/MoreOnClasses/src/main/java/com/oop/HybridVehicle.java b/MoreOnClasses/src/main/java/com/oop/HybridVehicle.java
new file mode 100644
index 0000000..e3c0b8a
--- /dev/null
+++ b/MoreOnClasses/src/main/java/com/oop/HybridVehicle.java
@@ -0,0 +1,7 @@
+package com.oop;
+
+public class HybridVehicle extends Vehicle {
+    public void resource(){
+        System.out.println("I use both petrol and electricity");
+    }
+}
diff --git a/MoreOnClasses/src/main/java/com/oop/Main.java b/MoreOnClasses/src/main/java/com/oop/Main.java
index 390240b..5b974fc 100644
--- a/MoreOnClasses/src/main/java/com/oop/Main.java
+++ b/MoreOnClasses/src/main/java/com/oop/Main.java
@@ -21,5 +21,45 @@ public class Main {
         pro1.write();
         pro1.useEffects();
         pro1.changeResolution();
+
+
+        //Polymorphism
+        // Vehicles can be classified according to what energy source powers them. The program you are given has 3 vehicle classes: Vehicle, ElectricVehicle and HybridVehicle.
+
+        // ElectricVehicle and HybridVehicle classes are inherited from Vehicle class.
+
+        // Complete the program by reimplementing method resource() in inherited classes, so that the given calls work correctly.
+
+        Vehicle vehicle = new Vehicle();
+        Vehicle electric = new ElVehicle();
+        Vehicle hybrid = new HybridVehicle();
+        
+        //calls
+        vehicle.start();
+        vehicle.resource();
+        electric.start();
+        electric.resource();
+        hybrid.start();
+        hybrid.resource();
+
+        //overriding funcions! For more visit Program.js
+        System.out.println(Program.max(8, 17));
+        System.out.println(Program.max(3.14, 7.68));
+
+        //Overloading or overriding
+        a = 5;
+        double b = 10.2;
+        
+        System.out.println(doubleTheValue(a));
+        System.out.println(doubleTheValue(b));
     }
+
+        //complete the method for integer value type
+        public static int doubleTheValue(int a) {
+            return a*2;
+        }
+        //overload the method for double value type
+        public static double doubleTheValue(double a) {
+            return a*2;
+        }
 }
\ No newline at end of file
diff --git a/MoreOnClasses/src/main/java/com/oop/Program.java b/MoreOnClasses/src/main/java/com/oop/Program.java
new file mode 100644
index 0000000..33e134d
--- /dev/null
+++ b/MoreOnClasses/src/main/java/com/oop/Program.java
@@ -0,0 +1,20 @@
+package com.oop;
+
+public class Program {
+    static double max(double a, double b) {
+        if(a > b) {
+            return a;
+        }
+        else {
+            return b;
+        }
+    }
+    static int max(int a, int b) {
+        if(a > b) {
+            return a;
+        }
+        else {
+            return b;
+        }
+    }
+}
diff --git a/MoreOnClasses/src/main/java/com/oop/Vehicle.java b/MoreOnClasses/src/main/java/com/oop/Vehicle.java
index 5aa01d2..b09fd7e 100644
--- a/MoreOnClasses/src/main/java/com/oop/Vehicle.java
+++ b/MoreOnClasses/src/main/java/com/oop/Vehicle.java
@@ -27,5 +27,11 @@ public class Vehicle {
     public void setColor(String c) {
       this.color = c;
     }    
-
+    public void start(){
+      System.out.println("Starting");
+    }
+    
+    public void resource(){
+      System.out.println("I use petrol");
+    }
 }
diff --git a/MoreOnClasses/target/classes/com/oop/ElVehicle.class b/MoreOnClasses/target/classes/com/oop/ElVehicle.class
new file mode 100644
index 0000000..f355d85
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diff --git a/MoreOnClasses/target/classes/com/oop/HybridVehicle.class b/MoreOnClasses/target/classes/com/oop/HybridVehicle.class
new file mode 100644
index 0000000..0657db0
Binary files /dev/null and b/MoreOnClasses/target/classes/com/oop/HybridVehicle.class differ
diff --git a/MoreOnClasses/target/classes/com/oop/Main.class b/MoreOnClasses/target/classes/com/oop/Main.class
index 41d020a..60141f0 100644
Binary files a/MoreOnClasses/target/classes/com/oop/Main.class and b/MoreOnClasses/target/classes/com/oop/Main.class differ
diff --git a/MoreOnClasses/target/classes/com/oop/Program.class b/MoreOnClasses/target/classes/com/oop/Program.class
new file mode 100644
index 0000000..8b7f12d
Binary files /dev/null and b/MoreOnClasses/target/classes/com/oop/Program.class differ
diff --git a/MoreOnClasses/target/classes/com/oop/Vehicle.class b/MoreOnClasses/target/classes/com/oop/Vehicle.class
index bb05307..35552fd 100644
Binary files a/MoreOnClasses/target/classes/com/oop/Vehicle.class and b/MoreOnClasses/target/classes/com/oop/Vehicle.class differ