Question

Assume that circle and objects are created as follows Circle circle = new Circle(1); GeometricObject object = new GeometricObject(); a) Are the following Boolean expressions true or false? (circle instanceof GeometricObject) (object instanceof GeometricObject) (circle instanceof Circle) (object instanceof Circle) b. Can the following statements be compiled? Circle circle = new Circle(5); GeometricObject object = circle;

Answer 1

Answer and Explanation:

The output is false because Circle is used. Circle class has two methods, such as ( Circle circle ) and Object o that defined in the Object class. The Circle class inherits it. Circle.euqlais equaled to Object o because it is the type of circle1 and circle 2. The object of Circle is match circle1. equal by the compiler.

The output is accurate if Circle class overrides the equals to defined in Object class. The circle is matched to equals to object and run time method implemented in Circle class.

Both Circle has a different address. With Circle.equals(circle 2) replaced and have a same method in Object class.

Yes the following statement can be compiled the Circle circle = new Circle(5);

Geometric Object object = circle;

In this Object o is used to compile and run time as the circle has a different address. Method overriding allows dynamic binding, but it is always determined by declared type.