Basic Inheritance

TruckDemo.java

//Vehicle.java
public class Vehicle {
        String color;
}

//Truck.java
public class Truck extends Vehicle {
        int bedLength;
}

//TruckDemo.java
class TruckDemo {
        public static void main(String[] args){
                Truck myTruck = new Truck();
                myTruck.bedLength = 2;
                System.out.println(myTruck.bedLength);
        }
}