Book Image

Oracle Certified Associate, Java SE 7 Programmer Study Guide

By : Richard M. Reese
Book Image

Oracle Certified Associate, Java SE 7 Programmer Study Guide

By: Richard M. Reese

Overview of this book

<p>Java SE 7 Associate Programmer certification adds to your qualification as a Java developer. Knowledge of Java is important, but knowing how to write an efficient and productive code adds to your skills and gives you an edge when you are planning to give the certification exam. Coverage of the objectives goes beyond a simple review of certification objectives.</p> <p>"Oracle Certified Associate, Java SE 7 Programmer Study Guide" addresses certification exam objectives and provides discussion and examples to show the best ways of applying Java language features in real world programming. You will gain in-depth understanding of Java by examining how objects are allocated in the heap and how methods are managed in the program stack.<br /><br />"Oracle Certified Associate, Java SE 7 Programmer Study Guide" covers all of the Java SE 7 Associate Programmer certification objectives. It starts with a high level overview of an application’s structure to provide a framework for subsequent chapters. Chapters are organized around common themes with emphasis on memory usage. You will get an in-depth and complete understanding of the run-time Java environment using the illustrations that show the impact of class and method usage on the program stack and heap. <br /><br />Augmenting the coverage of certification objectives are examples of how you can use the classes, methods, and techniques in a productive and sound manner. In addition, sample exam questions are given in each chapter.</p>
Table of Contents (16 chapters)
Oracle Certified Associate, Java SE 7 Programmer Study Guide
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface

Managing classes and objects


This section is concerned with a number of issues relating to the general management of classes and objects. It includes the:

  • Creation and initialization of objects

  • Accessing methods of a base class

  • Determining the type of objects

  • Use of the Object class

  • Casting objects

  • Controlling the scope of classes and members

The super keyword and constructors

As we saw in the Using the this Keyword section of Chapter 6, Classes, Constructors, and Methods, the this keyword refers to the current object. It can be used to:

  • Access instance variables

  • Pass the current object to a method

  • Return the current object from a method

The super keyword is used in a complementary fashion within a derived class. It is used to:

  • Call the base class constructor

  • Access an overridden method in the base class

Calling a base class constructor

Let's examine its use in calling base class constructors. When a derived class object is created, it is initialized by calling its constructor. The use of constructors is...