Ibm enterprise it and asset management 7.1 java for customization training

IBM Enterprise IT and Asset Management 7.1: Java for
Customization
Student’s Training Guide
S150-3087-00
May 2009

Copyright Notice
Copyright © 2009 IBM Corporation, including this documentation and all software. All rights
reserved. May only be used pursuant to a Tivoli Systems Software License Agreement, an IBM Soft-
ware License Agreement, or Addendum for Tivoli Products to IBM Customer or License Agreement.
No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system,
or translated into any computer language, in any form or by any means, electronic, mechanical,
magnetic, optical, chemical, manual, or otherwise, without prior written permission of IBM Corpora-
tion. IBM Corporation grants you limited permission to make hardcopy or other reproductions of any
machine-readable documentation for your own use, provided that each such reproduction shall carry
the IBM Corporation copyright notice. No other rights under copyright are granted without prior writ-
ten permission of IBM Corporation. The document is not intended for production and is furnished “as
is” without warranty of any kind. All warranties on this document are hereby disclaimed, including the
warranties of merchantability and fitness for a particular purpose.
Note to U.S. Government Users—Documentation related to restricted rights—Use, duplication or
disclosure is subject to restrictions set forth in GSA ADP Schedule Contract with IBM Corporation.
Trademarks
The following are trademarks of IBM Corporation or Tivoli Systems Inc.: IBM, Tivoli, AIX, Cross-Site,
NetView, OS/2, Planet Tivoli, RS/6000, Tivoli Certified, Tivoli Enterprise, Tivoli Ready, TME. In Den-
mark, Tivoli is a trademark licensed from Kjøbenhavns Sommer - Tivoli A/S.
Microsoft, Windows, Windows NT, and the Windows logo are trademarks of Microsoft Corporation in
the United States, other countries, or both.
UNIX is a registered trademark of The Open Group in the United States and other countries.
C-bus is a trademark of Corollary, Inc. in the United States, other countries, or both.
Java and all Java-based trademarks are trademarks of Sun Microsystems, Inc. in the United States,
other countries, or both.
Lotus is a registered trademark of Lotus Development Corporation.
PC Direct is a trademark of Ziff Communications Company in the United States, other countries, or
both and is used by IBM Corporation under license.
ActionMedia, LANDesk, MMX, Pentium, and ProShare are trademarks of Intel Corporation in the
United States, other countries, or both.
SET and the SET Logo are trademarks owned by SET Secure Electronic Transaction LLC. For fur-
ther information, see http://www.setco.org/aboutmark.html.
Other company, product, and service names may be trademarks or service marks of others.
Notices
References in this publication to Tivoli Systems or IBM products, programs, or services do not imply
that they will be available in all countries in which Tivoli Systems or IBM operates. Any reference to
these products, programs, or services is not intended to imply that only Tivoli Systems or IBM prod-
ucts, programs, or services can be used. Subject to valid intellectual property or other legally pro-
tectable right of Tivoli Systems or IBM, any functionally equivalent product, program, or service can
be used instead of the referenced product, program, or service. The evaluation and verification of
operation in conjunction with other products, except those expressly designated by Tivoli Systems or
IBM, are the responsibility of the user. Tivoli Systems or IBM may have patents or pending patent
applications covering subject matter in this document. The furnishing of this document does not give
you any license to these patents. You can send license inquiries, in writing, to the IBM Director of
Licensing, IBM Corporation, North Castle Drive, Armonk, New York 10504-1785, U.S.A.
Printed in Ireland.

•
•
•
•
•
I
Table of Contents
Preface
Course Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .X
Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .X
IBM Tivoli Technical Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .X
Tivoli User Group Community . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .X
Course Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XI
Course Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XI
Typographical Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XIII
Product Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XIII
Product Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . XIII
Unit 1: Objects and Object-Oriented Programming
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Evolution to Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Software Evolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Modeling Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Everything Is an Object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Object Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Similar Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
Keys to Object-Oriented Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Characteristics of an Object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
Car Object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
A Class Is the Blueprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12
Classes and Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14
The Car Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-15
An Object’s Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
Abstraction and Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18
Data Abstraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19
Inheritance and Composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20
Subclasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21
Object Interaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-22
Representing an Entity with Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-23
Classes and Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-24
Object Interaction and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-25
Class Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-26
Object-Oriented Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-27
Encapsulation and Information Hiding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-28
Inheritance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-29
Class Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-30
Polymorphism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31
One Interface, Multiple Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-32
Polymorphism and Inheritance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-33
Shape Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-34
Explaining Polymorphism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-35
Key Concepts and Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-36
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-37
Review Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-38
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-39

II IBM Enterprise IT and Asset Management 7.1: Java for Customization ©Copyright IBM Corp. 2009
•
•
•
•
•
Table of Contents
Course materials may not be reproduced in whole or in part without the prior written permission of IBM.
Unit 2: Programming with Java
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Lesson 1: The Java Programming Language . . . . . . . . . . . . . . . . . . . . . . . . . .2-3
The Java Platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Platform Independence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Just-in-Time Compiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Language Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
JDK, JRE, and JVM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Java API . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Types of Java Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Lesson 2: Development Environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2-11
Using the Eclipse IDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12
Creating Projects, Classes, and Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13
Running Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
Run Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15
Debugging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16
Debugging Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17
Breakpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18
Setting Breakpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19
Debug Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20
Student Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21
Review Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25
Unit 3: Java Basics and Operators
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Lesson 1: Class Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-3
File Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Package Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
import Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
import Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
Lesson 2: Language Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-13
Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
Variable Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
Built-in Data Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
Wrapper Classes for Primitives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
Primitives and References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19
Common Wrapper Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20
Assignment Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-22
Variables in Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23
Concatenation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
Print Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-25
Printing Newlines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
Lesson 3: Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-27
Assignment with Combination Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-28
Assignment Using the ++ and -- Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29
Relational Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-30
Relational Operator Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-31

©Copyright IBM Corp. 2009 IBM Enterprise IT and Asset Management 7.1: Java for Customization III
•
•
•
•
•
Table of Contents
Relational Operator Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-32
Common Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33
Comparing Primitives and Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-34
Logical Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-35
Ternary ? Operator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-36
Bitwise Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-37
Bitwise Shift Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-38
Operator Precedence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-39
Review Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-42
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-43
Unit 4: Java Basics and Programming Syntax
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Variable Declaration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Variable Access Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Method Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
Method Access Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
main() Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
main() Method Signature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Array Declaration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Allocating an Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11
Arrays in Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
Arrays Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
Arrays of Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
Declare an Array of Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15
Different Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
Constants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17
Variable Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18
Initial Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19
Casting Operator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-20
Literals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-21
if and if-else Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-23
if-else Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-24
if-else if Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-26
switch Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-27
break and continue Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-29
break Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-30
Loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-31
while Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-32
for Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-33
Comparing for and while Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-34
do-while Statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-36
Infinite Loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-37
foreach statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-38
Scope of a Variable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-39
Printing Program Arguments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-40
Add Program Arguments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-41
Conversions from String . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-42
Class Sum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-43
Review Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-46
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-47

IV IBM Enterprise IT and Asset Management 7.1: Java for Customization ©Copyright IBM Corp. 2009
•
•
•
•
•
Table of Contents
Unit 5: Classes, Constructors, and Strings
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Lesson 1: Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-3
Create Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Classes and Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Using new . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Garbage Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
Lesson 2: Constructors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-8
Default Constructor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Using the Keyword this . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10
Using the super() Keyword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11
Constructors versus Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12
Order of Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-13
Object Creation with Instance Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14
Static Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15
Static Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
Calling Static Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-17
Lesson 3: Java Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-18
Java Documentation Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19
Documentation Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-20
Lesson 4: String Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5-21
Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22
String Constructors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23
String Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-24
More String Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-26
Using String Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-27
Conversion Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-28
Comparison Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-29
Searching Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-30
Regular Expression Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-31
Conversions from String . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-32
Conversions to String . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-33
Using the split() Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-34
ConvertTemperature Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-35
ConvertTemperature Class Variation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-36
The convert() Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-37
Review Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-40
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-41
Unit 6: Java Exceptions, I/O, and Inheritance
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Lesson 1: Access Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-3
Access Control Modifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Access Control Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
abstract, final, and static Modifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Using the Keyword this . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
this Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Passing Arguments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10
Pass by Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11

©Copyright IBM Corp. 2009 IBM Enterprise IT and Asset Management 7.1: Java for Customization V
•
•
•
•
•
Table of Contents
Passing Objects by Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-12
Passing an Object Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13
A Copy of an Object Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
Pass by Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-15
Garbage Collection Revisited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-16
Garbage Collection and Object References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-17
Memory Leaks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18
Overloading Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-20
Guidelines for Overloading Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-21
Overloading versus Overriding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-23
Lesson 2: Exceptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-24
Exception Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-25
Exception Propagation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-26
Methods and Exceptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-27
Catching Exceptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-28
Rethrowing an Exception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-29
To Catch or Throw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-31
Java Exception Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-32
User-Defined Exceptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-33
Catch Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-34
try...finally Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-35
finally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-36
Lesson 3: Java I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-37
Streams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-38
Key Classes in java.io Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-39
Efficient I/O Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-40
The PrintWriter Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-41
Using Text Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-42
File I/O Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-44
Changing File Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-45
Lesson 4: Inheritance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6-46
Principles of Object-Oriented Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-47
The Object Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-48
The extends Keyword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-49
Constructor Execution Revisited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-50
Constructor Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-51
Constructors with and without Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-53
Abstract Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-55
Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-56
Multiple Inheritance with Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-57
Casting within the Class Hierarchy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-59
Casting Primitives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-60
Automatic Class Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-61
Automatic Interface Conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-62
Explicit Casts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-63
Upcasting and Downcasting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-65
Polymorphism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-66
Dynamic Binding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-67
Review Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-70
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-72

VI IBM Enterprise IT and Asset Management 7.1: Java for Customization ©Copyright IBM Corp. 2009
•
•
•
•
•
Table of Contents
Unit 7: Design Patterns, Interfaces, and the Collections
Framework
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Lesson 1: Design Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-3
Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4
Singleton Design Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
Using the Singleton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7
Proxy Design Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8
Adapter Design Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-9
Immutable Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10
Iterator Design Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-11
Generic Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12
Lesson 2: Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-13
An Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-14
Implementing an Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-15
Abstract Classes versus Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-16
Implementing Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-17
Interfaces and Polymorphism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-18
Extending Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-19
Extending Multiple Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-20
Nested and Inner Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-22
Lesson 3: The Collections Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7-23
Java Collections Framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-24
Basic Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-25
Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-26
Linked List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-27
Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-28
Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-29
Collection Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-30
Interface Implementations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-31
Navigating a Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-32
Original Enumeration Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-33
Review Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-36
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-37
Unit 8: Strings, Arrays, and Collection Classes
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2
Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2
Lesson 1: StringBuffer and StringBuilder . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-3
StringBuilder Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
StringBuilder Methods and Exceptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
StringBuilder Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8
Immutable Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9
Lesson 2: Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-11
Using Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12
Length of an Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13
foreach Loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-14
Array Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-15
ArrayList Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-16

©Copyright IBM Corp. 2009 IBM Enterprise IT and Asset Management 7.1: Java for Customization VII
•
•
•
•
•
Table of Contents
Lesson 3: Collections Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-17
Data Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-18
Collection Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-19
Collections Classes and Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-20
Map Classes and Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-21
Lesson 4: ArrayList<E> Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8-22
Choosing an ArrayList . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-23
ArrayList Constructors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-24
Searching, Adding, and Deleting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-25
Looping over an ArrayList . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-27
Iterator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-29
Iterator Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-30
Iterator Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-31
ListIterator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-32
ListIterator Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-33
Using an Iterator and Indexing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-34
LinkedList Class Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-35
LinkedList Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-36
Adding to a Linked List with fillList() . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-38
Iterating through a LinkedList . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-39
Autoboxing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-40
Review Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-44
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-45
Unit 9: Threads
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2
Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2
Lesson 1: Threading Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-3
Multithreaded Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4
Advantages and Disadvantages of Using Multiple Threads . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-5
The Life Cycle of a Thread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6
Threads and the Operating System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7
Preemptive Threading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-8
Priorities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-9
Thread States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-10
Blocking and Yielding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-11
Locks and Critical Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-12
Deadlock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-13
Semaphore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-14
Starvation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-15
Lesson 2: Implementing Threads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9-16
The Thread Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-17
The Runnable Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-18
Starting a Thread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-19
Thread Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-20
Extending the Thread Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-21
Running the Thread Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-22
Implementing the Runnable Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-24
Running the Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-25
Synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-26
Synchronization Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-27
The Producer-Consumer Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-29
Synchronized Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-32

VIII IBM Enterprise IT and Asset Management 7.1: Java for Customization ©Copyright IBM Corp. 2009
•
•
•
•
•
Table of Contents
Using wait() and notify() . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-33
Review Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-38
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-39
Unit 10: Serialization and Remote Method Invocation
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2
Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2
Lesson 1: Serialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-3
Serialization of an Object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4
Why Use Serialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-5
Static and Transient Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-6
Making a Class Serializable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-7
Implementing the Serializable Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-8
Instance and Superclass State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-9
equals() and hashCode() . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-10
Serialization Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-11
writeObject() and readObject() . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-12
Serialization Implementation Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-13
Serialization Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-14
Lesson 2: Remote Method Invocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10-15
Distributed Computing and RMI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-16
Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-17
Client and Server Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-18
RMI Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-19
Proxy Stubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-20
Remote Reference and Transport Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-21
Finding RMI Remote Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-22
RMI System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-23
HelloRemote Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-24
Hello Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-25
RMIServer Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-26
RMIClient Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-28
Invoking Remote Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-30
Student Exercise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-31
Review Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-32
Review Answers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-34
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-35
Tivoli Professional Certification
Special Offer for Having Taken This Course . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I
Reasons for Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I
Role-based Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I
When to Attempt a Certification Exam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II
Location and Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II
Sources of Additional Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II

•
•
•
•
•
IX
Preface
© 2009 IBM Corporation
Student Guide

X IBM Enterprise IT and Asset Management 7.1: Java for Customization ©Copyright IBM Corp. 2009
•
•
•
•
•
Preface
Course Description
The IBM Enterprise IT and Asset Management 7.1 Java for Customization course provides
hands-on training to learn Java™ programming skills using the Eclipse Integrated
Development Environment. This course includes Java and object-oriented fundamentals in
addition to advanced features of the language. These topics are prerequisite knowledge for
the IBM Enterprise IT and Asset Management 7.1 Customizing Business Objects course
and the IBM Integration Framework 7.1 Customization course.
Audience
This course is designed for developers, implementers, and administrators who want to learn
how to design, build, and debug Java applications. This course is also appropriate for those
who want to learn the more advanced Java topics presented in this course before attending
the IBM Enterprise IT and Asset Management 7.1 Customizing Business Objects course or
the IBM Integration Framework 7.1 Customization course.
IBM Tivoli Technical Education
The latest information about IBM Tivoli education offerings can be found online at
http://www.ibm.com/software/tivoli/education/
If you have any questions about education offerings, send an e-mail to the appropriate alias
for your region:
• Americas: tivamedu@us.ibm.com
• Asia Pacific: tivtrainingap@au1.ibm.com
• EMEA: tived@uk.ibm.com
Tivoli User Group Community
You can get even more out of Tivoli software by joining and participating in one of the 91
independently run Tivoli User Groups around the world. Learn about online and in-person
Tivoli User Group opportunities near you at www.tivoli-ug.org.

©Copyright IBM Corp. 2009 IBM Enterprise IT and Asset Management 7.1: Java for Customization XI
•
•
•
•
•
Preface
Course Objectives
Course Outline
The following outline is a high-level description of the contents of this course. Each unit
has an overview presentation, and most units have a series of student exercises designed to
reinforce the concepts presented. The course contains the following units:
• Unit 1: Objects and Object-Oriented Programming
This course covers the basics of the Java programming language. It also includes
classes and constructs specific to customizing integration framework and related
business objects. It does not include any graphical user interface or applet
programming.
• Unit 2: Programming with Java
This unit examines Java’s architecture and the basics of compiling and running
programs using the Java platform. Java allows you to write a program once and
run it on any platform.
IBM Software Group | Tivoli software
2
Course Objectives
Upon completion of this course, you will be able to:
• Identify object-oriented concepts and their advantages
• Write code using Java classes, operations, and program control
structures
• Use Java to design and code classes based on inheritance,
composition, and polymorphism
• Write and troubleshoot programs using the Eclipse IDE
• Use different classes included in the Java API (I/O, Collection
Framework, Strings, and so on)
• Write code that uses serialization, remote method invocation (RMI),
and threads

XII IBM Enterprise IT and Asset Management 7.1: Java for Customization ©Copyright IBM Corp. 2009
•
•
•
•
•
Preface
• Unit 3: Java Basics and Operators
This unit covers basic Java programming constructs and concepts.
• Unit 4: Java Basics and Programming Syntax
This unit covers the basics of the Java programming language and syntax.
• Unit 5: Classes, Constructors, and Strings
This unit examines the difference between classes and objects, and how objects
are constructed. The String class and its methods are introduced.
• Unit 6: Java Exceptions, I/O, and Inheritance
This unit covers access control for data and methods in more detail, in addition to
implementing inheritance and polymorphism with abstract classes and interfaces.
You will also implement Java exception handing and Java I/O basics.
• Unit 7: Design Patterns, Interfaces, and the Collections Framework
This unit covers design patterns, interfaces, and the Java Collections Framework.
• Unit 8: Strings, Arrays, and Collection Classes
This unit examines some of the Java Collection classes introduced in Unit 7 in
more detail.
• Unit 9: Threads
This unit focuses on extending the Thread class to create multiple threads, and
implementing the Runnable interface.
• Unit 10: Serialization and Remote Method Invocation
This unit covers object serialization and Remote Method Invocation. Using
serialization, you can save and reconstruct an object’s state. This process is used
when implementing Remote Method Invocation.

©Copyright IBM Corp. 2009 IBM Enterprise IT and Asset Management 7.1: Java for Customization XIII
•
•
•
•
•
Preface
Typographical Conventions
In this course, the following typographical conventions are used.
Product Information
Product Documentation
In some cases IBM Tivoli product documentation is available in the classroom or on the
Instructor Resources CD. For access to documentation outside the classroom environment,
visit the IBM Web site.
Convention Usage
Bold
Commands, keywords, file names, authorization roles,
URLs, or other information that you must use literally
appear in bold.
Italics
Variables and values that you must provide appear in
italics. Words and phrases that are emphasized also
appear in italics.
Bold Italics
New terms appear in bold italics when they are
defined in the text.
Monospace
Code examples, output, and system messages appear
in a monospace font.
>
In this manual, the arrow character is used as a path
arrow. The arrow indicates the path to the named
window.

XIV IBM Enterprise IT and Asset Management 7.1: Java for Customization ©Copyright IBM Corp. 2009
•
•
•
•
•
Preface

•
•
•
•
•
1-1
Unit 1: Objects and Object-Oriented
Programming
© 2009 IBM Corporation
Unit 1: Objects and Object-oriented
Programming

1-2 IBM Enterprise IT and Asset Management 7.1: Java for Customization ©Copyright IBM Corp. 2009
•
•
•
•
•
Introduction
This course covers the basics of the Java programming language. It also includes classes
and constructs specific to customizing integration framework and related business objects.
It does not include any graphical user interface or applet programming.
Objectives
2
Objectives
Upon completion of this unit, you will be able to:
Describe the following basic concepts of object-oriented programming:
– Abstraction
– Encapsulation
– Inheritance
– Polymorphism

©Copyright IBM Corp. 2009 IBM Enterprise IT and Asset Management 7.1: Java for Customization 1-3
•
•
•
•
•
Evolution to Objects
Large-scale software programs today are highly complex. Over time, the increasing
complexity of these systems gradually led to the need for a powerful, effective software
solution. That solution was object-oriented programming.
Complex systems, whether large businesses, public organizations, a cell phone, or a
hospital, can be modeled as objects.
3
Evolution to Objects
• Today’s business solutions are complex
• Objects can reflect the components of a complex solution
• Objects are used to model systems and their components

•
•
•
•
•
Software Evolution
Software evolution defines the process by which programs change and adapt.
Programming paradigms have undergone major shifts in the past 50 years to handle the
complexity of software development.
Modular programming allowed programs to branch to another part of the program.
Structured programming used a top-down design model and the overall program structure
maps to separate subsections. A function or set of similar functions were coded in separate
modules or submodules.
Later, stored procedures, a subroutine available to applications accessing a relational
database system, provided additional functionality.
In the mid-1980s, object-oriented programming became the industry standard using classes
written in C++. Ten years later, the Java programming language was introduced. Its ability
to be written once and run on multiple platforms has made Java the current programming
language of choice.
The older languages did not enforce any property or method boundaries, which often
resulted in unwanted side effects. Variables were changed or affected in unexpected ways,
and the code was difficult to understand and maintain.
4
Software Evolution

•
•
•
•
•
Modeling Objects
Complex systems exist everywhere. They can be independent or they can interact with
defined dependencies. Objects represent these systems.
An object can be used to model anything, such as a car engine, the human body, or a large-
scale organization.
5
Modeling Objects
• Objects are
everywhere
• Objects can be
independent
• Objects can
interact

•
•
•
•
•
Everything Is an Object
Anything can be modeled as an object. For example, a car engine with multiple interacting
parts can be represented as an object that contains a collection of interacting objects.
A cell (of the organic variety) also can be represented as an object. It has unique
characteristics and can interact with other cells, because complex organisms are
multicellular, with cooperative organ systems that perform complex activities.
A collection of objects is itself an object. A list is an object, and every object contained in
the list is also an object.
6
Everything Is an Object
• Anything can be modeled as an object
• A collection of objects is itself an object
Car engine
Hospital
Home theater system
• The contents of a collection are objects
Car engine contains an ignition, starter, and battery object
Hospital contains doctor, patient, lab test, and test request objects
Home theater system contains a DVD, speaker, and screen object

•
•
•
•
•
Object Hierarchy
Consider that a human body consists of many structures, including muscle, blood, and
nerve. Each of these structures is further composed of a collection of cells, and inside each
cell is yet another level of complexity. The parts form a hierarchy, and each level of this
hierarchy embodies its own complexity. This arrangement can be represented as a hierarchy
of objects.
A hospital could contain a laboratory, and the laboratory could be separated into a blood
laboratory, an X-ray laboratory, a pathology laboratory, and an ultrasound laboratory.
Object hierarchies model the specialization of objects.
7
Object Hierarchy
• Represents specialization of a more basic object
• Parent, base class, or superclass
• Child, subclasses, or
derived classes

•
•
•
•
•
Similar Objects
Objects might have a common interface but a dissimilar function.
For example, a saw and a table knife can both cut, and they both have a blade and handle,
but their purpose is functionally different.
With object-oriented programming, you can use this commonality between otherwise
unrelated objects and treat them identically.
8
Similar Objects
• Common interface
• Functionally similar but different purpose
• Both objects have a blade and can cut

•
•
•
•
•
Keys to Object-Oriented Technology
The objects themselves are the building blocks that provide the advantages of object-
oriented programming. The power of Java lies in its use of object hierarchies and
establishment of well-defined interaction between the objects.
9
Keys to Object-Oriented Technology
• Objects
• Interaction between objects
• Hierarchy of objects
• Object composition

•
•
•
•
•
Characteristics of an Object
An object models anything that is a part of an entity, or the entity itself.
Objects are described by their behavior and state. An object has methods, and its methods
reflect behavior. An object also contains variables, and its variables reflect its state.
Most objects are dependent. They typically are part of another object, or they collaborate
with other objects.
10
Characteristics of an Object
• Any object can be anything that
models a thing: a truck, a car, or
a bank statement
• An object has two aspects:
state and behavior
• An object’s methods reflect an
object’s behavior
• An object’s variables reflect an
object’s state
• Most objects act as part of a
system: a sound system, a
human body, or an engine

•
•
•
•
•
Car Object
An car object might contain an engine and a chassis, travel at a particular speed in a certain
direction, and contain a specific amount of fuel. These characteristics represent the car’s
properties. They are called data members, attributes, fields, variables, or state.
The behavior of the car might include starting, stopping, and turning. Behaviors are called
functions, methods, or member functions. These actions represent the car object’s
functionality.
11
Car Object
• An object has attributes
Attributes, data members,
fields, properties, data
• An object has functionality
Functions, methods, behaviors,
member functions

•
•
•
•
•
A Class Is the Blueprint
A class serves as a template or blueprint for an object. There might be tens of thousands of
cars that were created to match a design blueprint and are exactly the same. A single car is
an instance of the class of objects known as car. A class is the blueprint (or template) from
which individual objects are created.
The following Car class is a possible implementation of a car:
class Car {
String color;
String engineType;
int numberDoors = 4;
void start() {
...
}
void stop() {
...
}
void turn() {
}
}
12
A Class Is the Blueprint

•
•
•
•
•
The variables represent the object’s state, and the methods (functions) allow the object to
interact with other objects.

•
•
•
•
•
Classes and Objects
A class is a description of the objects that it represents. A class is used to instantiate (create
an instance of) an object. A class is the blueprint or template of an object; it is not the actual
object itself.
An object is an instantiation of a class. It models something in the real world. An object has
data (states) and methods (behaviors) as defined for the class of objects to which it belongs.
A class defines a new data type. A char, boolean, int, String, or Array is a data type. The
class Car creates another data type that can be used in the system.
13
Classes and Objects

•
•
•
•
•
The Car Class
The Car class includes (or encapsulates) attributes and methods that all instances of a Car
object will have. The class is made up of the properties and behavior that a Car object
represents.
The following example creates an instance of a Car object:
class Car {
private int aProperty;
private int anotherProperty;
public void aMethod() {
}
public void anotherMethod() {
}
}
public class MainApplication {
public static void main(String[] arg) {
Car carA = new Car();
Car carB = new Car();
}
14
The Car Class

•
•
•
•
•
An object has the properties and behaviors defined in a class. After you write the class
definition, you create one or more objects of that class using the new keyword.
To create a new object, type the word new followed by the name of the class, followed by
parentheses. You can also specify arguments in the parentheses when creating new objects.
When a new object is created, memory is allocated to hold the class variable plus additional
memory required by all objects.

•
•
•
•
•
An Object’s Interface
An object’s interface is how it represents itself to other objects.
Note: Do not confuse this term with the concept of interfaces, which will be covered in
Unit 7.
The methods and instance variables refer to functions and data that are stored in each
object. All variables and methods can be referenced using dot notation. To reference an
instance variable, type the object name, a dot, and then the variable name.
15
An Object’s Interface

•
•
•
•
•
Abstraction and Encapsulation
There are always clear boundaries between the outside and the inside of a specific level of
abstraction. For example, the parts of a muscle work together to provide the functionality
of the muscle as a whole. However, they have little or no direct interaction with the
elementary parts of blood. There is a distinct separation among the parts at different levels
of abstraction.
Abstraction and encapsulation are different but closely related object-oriented
concepts.
• Abstraction denotes an entity that is represented with a specific level of detail,
and unnecessary details are ignored.
• Encapsulation is the technique by which an object’s internal information and
functionality is hidden, and what is visible is intended to be visible. You can get
information from an object without all of its data being directly accessible.
16
Abstraction and Encapsulation
• Encapsulation and information hiding
• Data encapsulation versus data abstraction

•
•
•
•
•
Data Abstraction
All parts at the same level of abstraction interact in well-defined ways. For example, at a
high level of abstraction in a living body, muscle is controlled by the nervous system. At
lower levels of abstraction, muscle interacts with blood, which transports nutrients to the
muscles. The muscles in turn use the nutrients provided by the blood to produce energy and
respond to nerve stimuli.
In a similar manner, a car engine contains parts that interact in a well-defined way. An
ignition switch responds to the turn of a key. Battery voltage creates a magnet effect inside
the solenoid. When this connection is completed, current flows to start the engine.
Every object in these processes haves characteristics and well-defined functionality. The
highest level of abstraction is the engine itself. The next level could be a few components.
The lowest level could be millions of objects representing aluminium atoms.
17
Data Abstraction
• Data abstraction versus levels of abstraction

•
•
•
•
•
Inheritance and Composition
Good object-oriented design includes establishing relationships between classes. Classes
are usually related through inheritance or composition.
A car is composed of many objects. It has an engine object, a chassis object, and so on. The
human body is also composed of many objects. The relationship is one of composition and
is characterized by a has-a relationship.
A Prius™ is a type of car. The relationship is one of inheritance and is characterized as an
is-a type, which can be modeled with a hierarchical diagram.
Inheritance is a way of reusing behavior and data. Similar classes of objects can be
organized into categories to form class hierarchies. The subclasses can use the behavior of
higher classes (superclasses) in the hierarchy.
18
Inheritance and Composition
• Inheritance is an is-a relationship
between objects
• Composition is a has-a relationship
between objects

•
•
•
•
•
Subclasses
Classes can be derived from other classes. The derived class is called a subclass (or child
class). The class from which it is derived is called the superclass (or parent class).
A subclass inherits properties and behavior from all of its parent classes. The term
superclass refers to the direct parent, and all of the parent classes, of a class.
Use the extends clause in your class declaration to create a subclass of another class. As a
subclass, your class inherits member variables and methods from its superclass in addition
to adding its own. The subclass can use the inherited items from the superclass as is, or the
subclass can hide variables or override methods inherited from its superclass.
In Java, all classes are derived from some root class. The topmost class from which all
classes are derived is the Object class, which is defined in java.lang.
As the root of the class hierarchy, all objects inherit directly or indirectly from the Object
class.
19
Subclasses

•
•
•
•
•
Object Interaction
Typically, individual objects are each responsible for a small part in a single larger process.
There might be centralized objects that directly coordinate the activities of lower-level
objects. Some objects might act as independent agents, each of which might show highly
complex behavior and might contribute to many higher-level functions. High-level
functionality is realized through the mutual cooperation of meaningful collections of
objects.
A business can be a complex system: Multinational corporations contain companies, which
are made up of divisions, which contain branches, and so on. The relationships among the
various parts of a large organization are like those found among the cells in a living system.
The processes of employee interaction and the sharing of common facilities to accomplish
their tasks are defined and enforced with restrictive boundaries and business rules.
20
Object Interaction
• Object design is about
behavior
• Object design emphasizes
the interplay between objects
• Objects have responsibilities
• Objects act independently
and cooperatively
• Object relationships and
interaction determine design

•
•
•
•
•
Representing an Entity with Objects
Drawing an analogy between objects and a car engine or human cells can help you better
understand this concept. A car engine encapsulates its complexity under the vehicle hood.
The human cell encapsulates its internal complexity behind a cell membrane. The car
engine components communicate through electrical messages or signal to each other. Cells
communicate by sending chemical signals, each uniquely coded to elicit a particular
response from a cell when it penetrates the cell’s membrane.
Similar to the car engine or cell membrane, an object’s interface hides the object’s internal
complexity from the outside world. Communication with the object is achieved by sending
preestablished messages through the interface.
21
Representing an Entity with Objects
• Object complexity should be abstracted from user
• Complexity is encapsulated within the object itself
• Object’s interface should hide its internal complexity
• Object components communicate by sending messages
and requests to each other
• Communication is established through the object
interface

•
•
•
•
•
Classes and Interfaces
A class definition is a template from which objects can be created. A class definition
includes the variables (state information) and the capabilities (behaviors or methods) for
instances of that class. The class definition defines how an object (instance) of that class
behaves, but the class definition is not an object.
An interface is similar to a class but it has no instances. Interfaces are used to facilitate the
sharing of behavior among similar, more specialized classes. They are also used for sharing
behavior between objects that do not have a class relationship.
22
Classes and Interfaces
• A class definition is a template
• The class definition is not an object
• An interface is similar to a class:
Cannot be instantiated
Models similarities between otherwise unrelated objects

•
•
•
•
•
Object Interaction and Methods
Methods are how objects communicate. An object makes a request from another object by
sending a message in the form of a method call.
There are two types of methods: instance and static.
• Instance methods are associated with an instance of an object. These methods use
the instance variables of the object.
From outside the defining class, an instance method is called by using an object
name as a prefix, such as:
object1.setText("Hello");
• Static methods are associated with the class itself. They do not use instance
variables of any object of the class they are defined in.
A static method is called by using a class name as a prefix, such as:
Math.min(i,j);
23
Object Interaction and Methods
There are two types of methods: instance and static.
• Instance methods are associated with an instance of the object:
object1.setText("Hello");
• Static methods are associated with the class itself:
Math.min(i,j);

•
•
•
•
•
Class Example
Classes are composed of a name, attributes, and methods. The slide illustrates an example
of a class.
24
Class Example

•
•
•
•
•
Object-Oriented Concepts
All object-oriented programming languages provide mechanisms that help you implement
the object-oriented paradigm. These mechanisms are encapsulation, inheritance, and
polymorphism.
• Encapsulation is the means to get information from an object without its data
being directly accessible.
• Inheritance is a way of reusing behavior and data within a class. Similar classes
of objects can be organized into categories to form class hierarchies. The
subclasses can use the behavior of higher classes (superclasses) in the hierarchy.
• With the polymorphism feature, one interface can be used for a general set of
actions. The specific action is determined by the exact context of the situation.
25
Object-oriented Concepts
Fundamental mechanisms provided by object-oriented
languages:
Encapsulation
Inheritance
Polymorphism

•
•
•
•
•
Encapsulation and Information Hiding
The basis of encapsulation is the class. A class defines the data and behavior to be shared
by a set of objects. Each object of a class contains the structure and behavior defined by that
class. A class is a logical construct. An object has physical reality.
When you create a class, you specify the methods and data that constitute that class. The
data defined by the class is referred to as member variables or instance variables. The
operations on that data are referred to as methods. The methods define how the member
variables can be used.
The purpose of a class is to encapsulate complexity. There are mechanisms for hiding the
complexity of the implementation inside the class. Each method or variable in a class can
be marked public or private. The public interface of a class represents everything that other
objects can access. The private methods and private data can only be accessed by methods
of the class itself. Code that does not belong to the class cannot access a private method or
variable.
The private data members of a class can only be accessed by other parts of your program
through the public methods of the class. You can prevent undesirable actions by designing
the public interface to limit exposure to a class.
26
Encapsulation and Information Hiding
• Basis of encapsulation is the class
• Methods define how the
variables are used by other
objects
• The class encapsulates
complexity of the implementation
• The methods provide the class
interface and ensure that
unwanted actions do not occur

•
•
•
•
•
Inheritance
Inheritance is the process by which one object acquires the properties of another object.
This important process supports the concept of hierarchical classification. As mentioned
earlier, many relationship are made manageable by hierarchical (that is, top-down)
classifications.
Dog is part of the classification Mammal, which is under the larger classification Animal.
Without the use of hierarchies, each object would have to define all of its characteristics
explicitly. However, by using inheritance, an object must only define those qualities that
make it unique within its class. It can inherit its general attributes from its parent. Thus, the
inheritance mechanism makes it possible for one object to be a specific instance of a more
general case.
27
Inheritance
• Inheritance is a way for objects to define relationships
with each other
• Objects inherit characteristics from a parent object
• Parent object must be able to pass its state and methods
to its children
• Parent and child objects must have characteristics in
common
• Child objects (subclasses) are more specialized versions
of the parent object (superclass)

•
•
•
•
•
Class Hierarchy
Most people naturally view the world as made up of objects that are related to each other
in a hierarchical way, such as animals, mammals, and cows. To describe animals in an
abstract way, you would say that they have some attributes, such as size, intelligence, and
type of skeletal system. Animals also have certain behavioral aspects; they eat, breathe, and
sleep. This description of attributes and behavior is the class definition for animals.
To describe a more specific class of animals, such as mammals, you would use more
specific attributes, such as type of teeth, and mammary glands. This category is known as
a subclass of animals, where animals are referred to as mammals’ superclass.
Because mammals are simply more precisely specified animals, they inherit all of the
attributes from animals. A deeply inherited subclass inherits all of the attributes from each
of its ancestors in the class hierarchy.
28
Class Hierarchy
• Real-world objects can form
natural hierarchies
• A base class (superclass)
can be described in an
abstract way
• A more specialized class
can be described in a more
concrete way
• The specialized class
inherits everything from the
more general classes in the
hierarchy

•
•
•
•
•
Polymorphism
With the polymorphism (meaning many forms) feature, one interface can be used for a
general class of actions. The specific action is determined by the exact nature of the
situation.
Polymorphism is one of the fundamental principles of object-oriented programming. You
must understand inheritance before learning about polymorphism.
29
Polymorphism
• Means many forms
• One interface can be used to specify a general action

•
•
•
•
•
One Interface, Multiple Methods
More generally, the concept of polymorphism is often expressed by the phrase “one
interface, multiple methods.” This phrase means that you can design a generic interface to
a group of related activities. Being able to use the same interface to specify a general class
of action helps reduce complexity.
It is the compiler’s job to select the specific action (that is, method) as it applies to each
situation. You, the programmer, do not have to make this selection manually. You must only
remember and use the general interface.
30
One Interface, Multiple Methods

Ibm enterprise it and asset management 7.1 java for customization training

Ibm enterprise it and asset management 7.1 java for customization training

Recommandé

Recommandé

Contenu connexe

Tendances

Tendances (19)

Similaire à Ibm enterprise it and asset management 7.1 java for customization training

Similaire à Ibm enterprise it and asset management 7.1 java for customization training (20)

Dernier

Dernier (20)

Ibm enterprise it and asset management 7.1 java for customization training