write the following programs: Ram.java, Truck.java, LandVehicle.java and Vehicle.java.

0. public class Ram extends Truck { public static void main(String[] args) { 

    // your implementation } 

    public Ram() { // your implementation 

   } }

   public class Truck extends LandVehicle { public Truck() { 

    // your implementation } 

    public Truck(String s) { // your implementation 

   } }

   public class LandVehicle extends Vehicle { public LandVehicle() { 

    // your implementation } 

   }

   public class Vehicle { public Vehicle() { 

    // your implementation 

Requirements:

• Your Java class names must follow the names specified above. Note that they are case sensitive. See our template below.

• Class Ram contains a main method, which is the entrance of the program.

• Each class has to have its no-arg constructor. The behavior of the constructor is

  to print out a String. For example, class Truck's constructor will print "Truck's

  no-arg constructor is invoked.".