// ****************************************************************

// Dog.java

//

// A class that holds a dog's name and can make it speak.

//

// ****************************************************************

public class Dog

{

protected String name;

// ------------------------------------------------------------

// Constructor -- store name

// ------------------------------------------------------------

public Dog(String name)

{

this.name = name;

}

// ------------------------------------------------------------

// Returns the dog's name

// ------------------------------------------------------------

public String getName()

{

return name;

}

// ------------------------------------------------------------

// Returns a string with the dog's comments

// ------------------------------------------------------------

public String speak()

{

return "Woof";

}

}

-------------------------------------------------------------------------------------------

// ****************************************************************

// Labrador.java

//

// A class derived from Dog that holds information about

// a labrador retriever. Overrides Dog speak method and includes

// information about avg weight for this breed.

//

// ****************************************************************

public class Labrador extends Dog

{

private String color; //black, yellow, or chocolate?

private int breedWeight = 75;

public Labrador(String name, String color)

{

this.color = color;

}

// ------------------------------------------------------------

// Big bark -- overrides speak method in Dog

// ------------------------------------------------------------

public String speak()

{

return "WOOF";

}

// ------------------------------------------------------------

// Returns weight

// ------------------------------------------------------------

public static int avgBreedWeight()

{

return breedWeight;

}

}

-------------------------------------------------------------------------------------------

// *****************************************************************

// Yorkshire.java

//

// A class derived from Dog that holds information about

// a Yorkshire terrier. Overrides Dog speak method.

//

// *****************************************************************

public class Yorkshire extends Dog

{

public Yorkshire(String name)

{

super(name);

}

// -------------------------------------------------------------

// Small bark -- overrides speak method in Dog

// -------------------------------------------------------------

public String speak()

{

return "woof";

}

}

-------------------------------------------------------------------------------------------

// ****************************************************************

// DogTest.java

//

// A simple test class that creates a Dog and makes it speak.

//

// ****************************************************************

public class DogTest

{

public static void main(String[] args)

{

Dog dog = new Dog("Spike");

System.out.println(dog.getName() + " says " + dog.speak());

}

}

File Dog java contains a declaration for a Dog class. Save this file to your directory and study it notice what instance variables and methods are provided. Files Labrador,java and Yorkshirejava contain declarations for classes that extend Dog. Save and study these files as well. File DogTestjava contains a simple driver program that creates a dog and makes it speak. Study Dog Testjava, save it to your directory, and compile and run it to see what it does. Now modify these files as follow 1. Add statements in DogTest,java after you create and print the dog to create and print a Yorkshire and a Labrador. Note that the Labrador constructor takes two parameters: the name and color of the labrador. both strings. Don't change any files besides Dog Test,java. Now recompile Dog Test,java; you should get an error saying something like /Labrador ava: 18 Dog (java lang String in Dog cannot be applied to 1 error If you look at line 18 of Labrador java it's just a f, and the constructor the compiler can't find (Dog0) isn't alled anywhere in this file a. What's going on? (Hint: What call must be made in the constructor of a subclass? b. Fix the problem (which really is in Labrador) so that DogTest,java creates and makes the Dog Labrador, and Yorkshire all speak. 2. Add code to Dog Test java to print the average breed weight for both your Labrador and your Yorkshire. Use the aygBreedWeight0 method for both. What error do you get? Why? Fix the problem by adding the needed code to the Yorkshire class 3. Add an abstract intagBreedWeighto method to the Dog class. Remember that this means that the word semicolon after the parameter list). It makes sense for this to be abstract, since Dog has no idea what breed it is. Now any subclass of Dog must have an ay Weight method; since both Yorkshire and Laborador gBreed do, you should be all set. Save these changes and recompile Dog Testjava. You should get an error in Dogjava (unless you made more changes than described above). Figure out what's wrong and fix this error, then recompile Dog Test java. You should get another error, this time in DogTestjava. Read the error message carefully; it tells you exactly what the problem is. Fix this by changing DogTest (which will mean taking some things out)