Complete VMS with polymorphism demonstration

src/main/java/org/model/Vehicle.java

@@ -20,13 +20,36 @@ public abstract class Vehicle {
         this.mileage = mileage;
     }
 
-    // TODO: Create getters for all fields
+    public String getBrand() {
 
-    // TODO: Implement addMileage(double km)
-    // If km is negative → print error
-    // Otherwise increase mileage
+        return brand;
+    }
 
-    // TODO: Declare abstract method getEnergyType()
+    public String getModel() {
+
+        return model;
+    }
+
+    public int getYear() {
+
+        return year;
+    }
+
+    public double getMileage() {
+
+        return mileage;
+    }
+
+
+    public void addMileage(double km) {
+        if ( km < 0 ) {
+            System.out.println("Error: Mileage cannot be negative!");
+            return;
+        }
+        this.mileage += km;
+    }
+
+    public abstract String getEnergyType();
 
     public void basicInfo() {
         System.out.println(