Making sure that encapsulation is not violated (i.e., instance variables must be private); design an inheritance hierarchy of classes Car, Truck, and Vehicle based on the following description. Car is a Vehicle. Truck is a Vehicle.   (a) Definition of class Vehicle Instance variables: year                 that holds the year of vehicle (int) make               that holds the make of vehicle (string)   Methods: a default constructor with no arguments. a second constructor that accepts the Vehicle's year and the make as arguments. These values should be assigned to the object's instance variables: year and make.  A copy constructor that accepts an existing vehicle object reference as argument and copies the values of instance variables to the newly created object.   Accessor methods (getYear() and getMake()) that get the values of instance variables.   Mutator methods (setYear(int) and setMake(String)) that set the values of instance variables.   toString() should return a string with the values of instance variables of vehicle object as follows. For example, the method should return the following string for a vehicle Ford 2022.   year: 2022, make: Ford   equals() should accept a vehicle object reference as argument and return true if all instance variables of calling object are same values as those of passed vehicle object, respectively, or false otherwise.   brake() should do nothing (i.e., empty body). This method is for polymorphism to call appropriate brake() method of subclass.   (b) Definition of class Car, which is a subclass of Vehicle. Instance variables: speed              that holds the car's current speed (int)   Methods: a default constructor with no arguments. another constructor that accepts the car's year and make, as arguments and should assign them to the object's instance variables.  A copy constructor that accepts an existing Car object reference as argument and copies the values of instance variables to the newly created object.   Accessor methods (getSpeed()) that get the values of instance variables.   Mutator methods (setSpeed()) that set the values of instance variables with those of argument values.   toString() should return a formatted string with the values of instance variables of a car. For example, the method should return the following string for a car Toyota 2023 at speed 95.   Car year: 2023, make: Toyota, current speed: 95            This toString() should call the parent class's toString() method to return the string given above.   equals() should accept a Car object reference as argument and return true if all instance variables of calling object are same values as those of passed Car object, respectively, or false otherwise.   accelerate() should receive an argument for maximum speed limit. It should add 20 to instance variable speed, each time accelerate() is called. It should limit the speed, i.e., this method can't change speed to more than the maximum speed limit.   brake() method should subtract 10 from the instance variable speed, each time brake() is called. The value of instance variable speed can't be less than 0, i.e., this method can't change speed to less than 0.   sameSpeed() method should accept a Car object reference as argument, and return true if the speed of the calling object is the same as that of passed object, and false otherwise.   (c) Definition of class Truck, which is a subclass of Vehicle. Instance variables: speed holds the truck's current speed (int)   Methods: a default constructor with no arguments. another constructor that accepts the truck's year, make and initial speed as arguments. These values should be assigned to object's instance variables: year, make, and speed.  Accessor method (getSpeed() method) that gets the value of instance variable.   Mutator method (setSpeed() method) that sets the value of instance variable with that of argument.   toString() should returns a formatted string with the values of instance variables of a truck. For example, the method should return the following string for a truck Toyota 2023 at speed 95.   Truck year: 2023, make: Toyota, current speed: 95            This toString() should call the parent class's toString() method to return the string given above.   accelerate() should receive an argument for maximum speed limit. It should add 10 to instance variable speed, each time accelerate() is called. It should limit the speed, i.e., this method can't change speed to more than the maximum speed limit.   brake() method should subtract 5 from the instance variable speed each time brake() is called. The value of instance variable speed can't be less than 0, i.e., this method can't change speed to less than 0.

Making sure that encapsulation is not violated (i.e., instance variables must be private); design an inheritance hierarchy of classes Car, Truck, and Vehicle based on the following description.

Car is a Vehicle. Truck is a Vehicle.

(a) Definition of class Vehicle

Instance variables:

• year                 that holds the year of vehicle (int)
• make               that holds the make of vehicle (string)

Methods:

• a default constructor with no arguments.
  
  
• a second constructor that accepts the Vehicle's year and the make as arguments. These values should be assigned to the object's instance variables: year and make. 
  
  
• A copy constructor that accepts an existing vehicle object reference as argument and copies the values of instance variables to the newly created object.

• Accessor methods (getYear() and getMake()) that get the values of instance variables.

• Mutator methods (setYear(int) and setMake(String)) that set the values of instance variables.

• toString() should return a string with the values of instance variables of vehicle object as follows. For example, the method should return the following string for a vehicle Ford 2022.

year: 2022, make: Ford

• equals() should accept a vehicle object reference as argument and return true if all instance variables of calling object are same values as those of passed vehicle object, respectively, or false otherwise.

• brake() should do nothing (i.e., empty body). This method is for polymorphism to call appropriate brake() method of subclass.

(b) Definition of class Car, which is a subclass of Vehicle.

Instance variables:

• speed              that holds the car's current speed (int)

Methods:

• a default constructor with no arguments.
  
  
• another constructor that accepts the car's year and make, as arguments and should assign them to the object's instance variables. 
  
  
• A copy constructor that accepts an existing Car object reference as argument and copies the values of instance variables to the newly created object.

• Accessor methods (getSpeed()) that get the values of instance variables.

• Mutator methods (setSpeed()) that set the values of instance variables with those of argument values.

• toString() should return a formatted string with the values of instance variables of a car. For example, the method should return the following string for a car Toyota 2023 at speed 95.

Car year: 2023, make: Toyota, current speed: 95

         This toString() should call the parent class's toString() method to return the string given above.

• equals() should accept a Car object reference as argument and return true if all instance variables of calling object are same values as those of passed Car object, respectively, or false otherwise.

• accelerate() should receive an argument for maximum speed limit. It should add 20 to instance variable speed, each time accelerate() is called. It should limit the speed, i.e., this method can't change speed to more than the maximum speed limit.

• brake() method should subtract 10 from the instance variable speed, each time brake() is called. The value of instance variable speed can't be less than 0, i.e., this method can't change speed to less than 0.

• sameSpeed() method should accept a Car object reference as argument, and return true if the speed of the calling object is the same as that of passed object, and false otherwise.

(c) Definition of class Truck, which is a subclass of Vehicle.

Instance variables:

• speed holds the truck's current speed (int)

Methods:

• a default constructor with no arguments.
  
  
• another constructor that accepts the truck's year, make and initial speed as arguments. These values should be assigned to object's instance variables: year, make, and speed. 
  
  
• Accessor method (getSpeed() method) that gets the value of instance variable.

• Mutator method (setSpeed() method) that sets the value of instance variable with that of argument.

• toString() should returns a formatted string with the values of instance variables of a truck. For example, the method should return the following string for a truck Toyota 2023 at speed 95.

Truck year: 2023, make: Toyota, current speed: 95

         This toString() should call the parent class's toString() method to return the string given above.

• accelerate() should receive an argument for maximum speed limit. It should add 10 to instance variable speed, each time accelerate() is called. It should limit the speed, i.e., this method can't change speed to more than the maximum speed limit.

• brake() method should subtract 5 from the instance variable speed each time brake() is called. The value of instance variable speed can't be less than 0, i.e., this method can't change speed to less than 0.