![]() 10.7 Case Study: Creating and Using Interfaces.10.5.7 Summary of the Allowed Assignments Between Superclass and Subclass Variables.10.5.6 Demonstrating Polymorphic Processing, Operator instanceof and Downcasting.10.5.5 Creating Indirect Concrete Subclass BasePlusCommissionEmployee.10.5.4 Creating Concrete Subclass CommissionEmployee.10.5.3 Creating Concrete Subclass HourlyEmployee.10.5.2 Creating Concrete Subclass SalariedEmployee.10.5.1 Creating Abstract Superclass Employee.10.5 Case Study: Payroll System Using Polymorphism.10.3 Demonstrating Polymorphic Behavior. ![]() Even his most abstract ideas are, to some extent, conditioned by what is or is not known in the time when he lives. General propositions do not decide concrete cases.Ī philosopher of imposing stature doesn't think in a vacuum. One Ring to rule them all, One Ring to find them, One Ring to bring them all and in the darkness bind To determine an object's type at execution time.How polymorphism makes systems extensible and maintainable.To declare abstract methods to create abstract classes.To distinguish between abstract and concrete classes.To use overridden methods to effect polymorphism.For more info, please visit: Safari Books Online subscribers can access the book here: Objectives If the above mentioned example is a skeleton of how a method is sharable in two classes then following is the Illustration 4.2 giving executable code how member elements are sharable.This chapter is an excerpt from the book, Java for Programmers, authored by Paul and Harvey Deitel, part of the Deitel Developer Series, ISBN 0137001290, published in Feb 2009 by Prentice Hall Professional, Copyright 2009 Pearson Education, Inc. Note that for object.bioData( ) at line 5, and object.bioData ( ) at line 7 of the above piece of codes, the respective codes for preparing bio-data of Teacher and Student will be in effect. bioData // Obtain the bio-data of a student Y bioData ( ) // Obtain the bio-data of a teacher X Resume object // Object is reference to an instance of Resume. Student y = new Student ( ) // Y is an instance of Student Teacher x = new Teacher ( ) // X is an instance of Teacher We can, therefore, run the following through a main class which extends the above defined interface, namely Resume. With this definitions it should be noted that the method (s ) which is / are in interface must be defined in their respective classes with which the interface is implemented. In this example, the interface Resume is declared which is implemented by two classes: Teacher and Students Teacher is an inherited class from a class Employee ( the definition of all classes are understood ). Code for the method for preparing the bio-data of a student // Code for this method for preparing the bio-data of a teacher // ![]() Interface InterfaceName // A member function Let us first take a look at the general form of an interface definition. Like classes, interfaces contain methods and variables unlike classes, interfaces are always completely abstract. ![]() This Chapter is for getting a lesson of Interfaces and Packages.Īn interface in Java is essentially a special kind of class. By organizing the users classes into packages, their reusing to write other classes are easier. Packages are containers for classes that are used to keep the class name space compartmentalized. Another unique feature in Java is Packages. There is no concept of multiple-inheritance in Java, but, Interfaces in Java are, for the most part, unique to the language, play a role similar to that of multiple-inheritance. Chapter 4 - Interfaces and Packages in Java Chapter 4 Interfaces and Packages in Java ![]()
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