hello i'm getting some errors in this java program:

here is the code:

Exercise 11-4 Inherit the Product class In this exercise, you'll modify a version of the Product application so it adds a class named MyProduct that extends the Product class and enhances its functionality Review the application 1. Open the project named chll_ex4_Product in the extra_ ex_starts directory. 2. Open the classes and review their code. 3. Run the application to make sure it works correcty. Create a new subclass and use it 4. In the murach.business package, create a new class named MyProduct that inherits the Product class. This new class should add the following method to the Product class: public String getPrice(NumberFormat nf) This method should format the price for the product using the format that's provided by the NumberFormat object that's passed as a parameter. 5. In the ProductDB class, modify the getProduct method so it returns a MyProduct object, not a Product object. In the ProductApp class, modify the code so it uses a MyProduct object, not a Product object. This should include using the getPrice method that's only available from the MyProduct class to apply currency formatting to the price. 6. 7. Run the application to make sur that it sil works correcty