Assume the availability of an existing class, ICalculator , that models an integer arithmetic calculator and contains:   an instance variable currentValue that stores the current int value of the calculator and can be accessed and modified by any subclass methods add , sub , mul , and div Each method in ICalculator receives an int argument and applies its operation to currentValue and returns the new value of currentValue . So, if currentValue has the value 8 and sub(6) is invoked then currentValue ends up with the value 2 , and 2 is returned. Write a public subclass, ICalculator2 , based on ICalculator . The class ICalculator2 has one additional method, negate , that receives no arguments. The effect of negate is to reverse the sign of currentValue . For example, if currentValue is zero, there is no change, if it is -22 then it becomes 22 , if it is 100 it becomes -100 . Furthermore negate returns the new value of currentValue Assume that variable currentValue is accessible in the subclass

Subclasses of abstract classes must implement the parent class's abstract methods. You think?

Design a console program that will print details of DVDs available to buy. Make use of an abstract class DVD with variables that will store the title, yearReleased, running time and price of a DVD. Create a constructor that accepts the title, yearReleased and running time through parameters and assign these to the class variables. Create an abstract set method for the price of a DVD; also create get methods for the variables.Create a subclass InstructionalDVD that extends the DVD class and implements an iPrintable interface. The interface that must be added is shown below:public interface iPrintable { String ShowDetails();}The InstructionalDVD subclass has a private variable named category for which a get method must be written. The constructor of the InstructionalDVD class must accept the title, yearReleased, running time and category through parameters. Write the code for the setPrice() and ShowDetails() methods.Write a useDVD class and instantiate 2 objects of the InstructionalDVD…