اخواني مبرمجين الجافا كل عام وانتم بخير الرجاء مساعدتي في حل هالسؤال : Q2.1: Write a Java program according to the following specifications: (a) Develop an interface ShapeInterface to the following specifications: • The interface includes one method: public double getArea(). Later when getArea() is implemented in a class, it should return a number representing the area of the relevant shape. (b) Develop a public abstract class Shape to the following specifications: (4 marks) • The class implements ShapeInterface. • The class has two private instance variables: int x, and int y . • Accessor and mutator methods should be implemented for all instance variables. © Develop a public class Circle to the following specifications: (4 marks) • The class is a subclass of Shape. • The class has a private instance variable int radius. • The class has a three-argument constructor that sets the values of x, y, and radius to given values. • The class has a one-argument constructor that sets the values of rad to given value, and x and y to zeros. This should be done by invoking the above three-argument constructor using this keyword. (d) Develop a public class Rectangle to the following specifications: (4 marks) • The class is a subclass of Shape. • The class has two private instance variables int height and int width. • The class has a four-argument constructor that sets the values of x, y, width and height to given values. • The class has a two-argument constructor that sets the values of width and height to given values, and x and y to zeros. This should be done by invoking the above four-argument constructor using this keyword. (e) Both Circle and Rectangle classes should: (8 • override toString() in java.lang.Object to return a string representation of the instance variables in the relevant class. • include implementation of any further mandatory methods. • include accessor and mutator methods for all instance variables. Q2.2: Develop a class ShapesTest to test the classes in Q2.1. The class ShapesTest will only have the main method that should: (4 marks) • Create a Circle instance using the three argument constructor. • Create a Rectangle instance using the two argument constructor, and sets the values of the remaining variables using the mutator methods. • Print on the screen the values of the instance variables of the two above instances using toString(). Q2.3: Answer the following questions: (4 marks) (a) Can we instantiate objects of the type Shape? Justify your answer. (b) Do we have to override getArea()in Shape class (you may try this on NetBeans)? Justify your answer
