OReilly java cookbook 2nd edition jun 2004 ISBN 0596007019

I'll presume you've taken a Java course or studied an introductory book such as O'Reilly's Head First Java, Learning Java, or Java in a Nutshell.. Many of the longer examples in this boo

tools and delivers expanded Mac OS

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Preface to the Second EditionPreface to the First EditionWho This Book Is For

What's in This Book?

Platform Notes

Other Books

Conventions Used in This BookComments and Questions

Getting the Source Code

Acknowledgments

JDK 1.5, code-named Tiger, is an exciting change to the Javalandscape It introduces several major new facilities, such asgeneric types for better data structuring, metadata for

annotating Java© classes in a flexible but well-defined manner,new pattern-based mechanisms for reading data, and a newmechanism for formatted printing In addition, a much largernumber of smaller but important changes add up to a new

release that is a must for Java developers It will be quite sometime before these mechanisms are fully understood and in widecirculation, but you will want to know about them right away

I wrote in the Afterword to the first edition that "writing thisbook has been a humbling experience." I should add that

maintaining it has been humbling, too While many reviewersand writers have been lavish with their praiseone very kind

reviewer called it "arguably the best book ever written on theJava programming language"I have been humbled by the

number of errors and omissions in the first edition In preparingthis edition, I have endeavored to correct these

At the same time I have added a number of new recipes andremoved a smaller number of old ones The largest single

addition is Chapter 8, which covers generic types and

enumerations, features that provide increased flexibility for

containers such as Java Collections Now that Java includes aregular expressions API, Chapter 4 has been converted from theApache Regular Expressions API to JDK 1.4 Regular

Expressions

I have somewhat hesitantly removed the chapter on NetworkWeb, including the JabaDot Web Portal Site program This wasthe longest single program example in the book, and it was

showing signs of needing considerable refactoring (in fact, itneeded a complete rewrite) In writing such a web site today,

Linux and Windows

I wish to express my heartfelt thanks to all who sent in bothcomments and criticisms of the book after the first English

edition was in print Special mention must be made of one ofthe book's German translators,[1] Gisbert Selke, who read thefirst edition cover to cover during its translation and clarified myEnglish Gisbert did it all over again for the second edition andprovided many code refactorings, which have made this a farbetter book than it would be otherwise Going beyond the call ofduty, Gisbert even contributed one recipe (Recipe 26.4) andrevised some of the other recipes in the same chapter Thankyou, Gisbert! The second edition also benefited from comments

by Jim Burgess, who read large parts of the book Comments

on individual chapters were received from Jonathan Fuerth, Kim

My thanks to the good guys behind the O'Reilly "bookquestions"list for fielding so many questions Thanks to Mike Loukides,Deb Cameron, and Marlowe Shaeffer for editorial and

production work on the second edition

mangled C/C++ I wrote test and demo programs, sticking

them a few at a time into a directory that I called javasrc to

keep it separate from my C source (because often the programswould have the same name) And as I learned more about Java,

I began to see its advantages for many kinds of work, such asthe automatic memory reclaim and the elimination of pointer

calculations The javasrc directory kept growing I wrote a Java

course for Learning Tree,[2] and the directory grew faster,

reaching the point where it needed subdirectories Even then, itbecame increasingly difficult to find things, and it soon becameevident that some kind of documentation was needed

[2] One of the world's leading high-tech, vendor-independent training companies; see

http://www.learningtree.com/

In a sense, this book is the result of a high-speed collision

between my javasrc directory and a documentation framework established for another newcomer language In O'Reilly's Perl

Cookbook, Tom Christiansen and Nathan Torkington worked out

a very successful design, presenting the material in small,

focused articles called "recipes." The original model for such abook is, of course, the familiar kitchen cookbook Using the

term "cookbook" to refer to an enumeration of how-to recipesrelating to computers has a long history On the software side,

"learn more Java."

copyright, just to discourage wholesale reproduction

I'm going to assume that you know the basics of Java I won'ttell you how to println a string and a number at the same

time, or how to write a class that extends Applet and printsyour name in the window I'll presume you've taken a Java

course or studied an introductory book such as O'Reilly's Head

First Java, Learning Java, or Java in a Nutshell However,

Chapter 1 covers some techniques that you might not knowvery well and that are necessary to understand some of thelater material Feel free to skip around! Both the printed version

of the book and the electronic copy are heavily cross-referenced

Unlike my Perl colleagues Tom and Nathan, I don't have to

spend as much time on the oddities and idioms of the language;Java is refreshingly free of strange quirks But that doesn't

mean it's trivial to learn well! If it were, there'd be no need forthis book My main approach, then, is to concentrate on theJava APIs I'll teach you by example what the APIs are and

what they are good for

Like Perl, Java is a language that grows on you and with you.And, I confess, I use Java most of the time nowadays ThingsI'd once done in C are nowexcept for device drivers and legacysystemsdone in Java

But Java is suited to a different range of tasks than Perl Perl(and other scripting languages, such as awk and Python) areparticularly suited to the "one-liner" utility task As Tom andNathan show, Perl excels at things like printing the 42nd linefrom a file While it can certainly do these things, Java, because

it is a compiled, object-oriented language, seems more suited

to "development in the large" or enterprise applications

development Indeed, much of the API material added in Java 2was aimed at this type of development However, I will

necessarily illustrate many techniques with shorter examplesand even code fragments Be assured that every line of codeyou see here has been compiled and run

Many of the longer examples in this book are tools that I

originally wrote to automate some mundane task or another.For example, MkIndex (described in Chapter 17) reads the top-level directory of the place where I keep all my Java example

source code and builds a browser-friendly index.html file for

that directory For another example, the body of the first editionwas partly composed in XML, a simplification that builds uponmany years of experience in SGML (the parent standard that led

XmlForm program This program also handlesby use of anotherprogram, GetMarkfull and partial code insertions from the

source directory XmlForm is discussed in Chapter 21

Let's go over the organization of this book I start off Chapter 1,

by describing some methods of compiling your program on

different platforms, running them in different environments

(browser, command line, windowed desktop), and debugging.Chapter 2, moves from compiling and running your program togetting it to adapt to the surrounding countrysidethe other

programs that live in your computer

The next few chapters deal with basic APIs Chapter 3,

concentrates on one of the most basic but powerful data types

in Java, showing you how to assemble, dissect, compare, andrearrange what you might otherwise think of as ordinary text

Chapter 4, teaches you how to use the powerful regular

expressions technology from Unix in many string-matching andpattern-matching problem domains JDK 1.4 was the first

release to include this powerful technology; I also mention

several third-party regular expression packages

Chapter 5, deals both with built-in types such as int and

double, as well as the corresponding API classes (Integer,

Double, etc.) and the conversion and testing facilities they offer.There is also brief mention of the "big number" classes SinceJava programmers often need to deal in dates and times, bothlocally and internationally, Chapter 6, covers this important

topic

languages, arrays in Java are linear, indexed collections of

similar-kind objects, as discussed in Chapter 7 This chaptergoes on to deal with the many "Collections" classes: powerfulways of storing quantities of objects in the java.util package

A new chapter was added in this section of the second edition.JDK 1.5 introduced a new dimension to the notion of data

structuring, by adapting the C++ notion of templates to theJava Collections; the result known as Generics is the main

subject of Chapter 8

Despite some syntactic resemblance to procedural languagessuch as C, Java is at heart an object-oriented programminglanguage Chapter 9, discusses some of the key notions of OOP

as it applies to Java, including the commonly overridden

methods of java.lang.Object and the important issue of

Design Patterns

The next few chapters deal with aspects of traditional input andoutput Chapter 10, details the rules for reading and writingfiles (Don't skip this if you think files are boring, as you'll needsome of this information in later chapters: you'll read and write

on serial or parallel ports in Chapter 12 and on a socket-basednetwork connection in Chapter 16!) Chapter 11, shows you

modified timeand about reading and modifying directories,

everything else about filessuch as finding their size and last-creating temporary files, and renaming files on disk Chapter

12, shows how you can use the javax.comm API to read/write

on serial and parallel ports using a standard Java API

Chapter 13, leads us into the GUI development side of things.This chapter is a mix of the lower-level details, such as drawinggraphics and setting fonts and colors, and very high-level

activities, such as controlling a video clip or movie In Chapter

14, I cover the higher-level aspects of a GUI, such as buttons,labels, menus, and the likethe GUI's predefined components.Once you have a GUI (really, before you actually write it), you'll

do in Alberta, Arkansas, or Alabama

Since Java was originally promulgated as "the programminglanguage for the Internet," it's only fair that we spend some ofour time on networking in Java Chapter 16, covers the basics

of network programming from the client side, focusing on

sockets We'll then move to the server side in Chapter 17 InChapter 18, you'll learn more client-side techniques Programs

on the Net often need to generate electronic mail, so this

section ends with Chapter 19

Chapter 20, covers the essentials of the Java Database

Connectivity (JDBC) and Java Data Objects (JDO) packages,showing how you can connect to local or remote relational

databases, store and retrieve data, and find out informationabout query results or about the database

Another form of storing and exchanging data is XML Chapter

21, discusses XML's formats and some operations you can applyusing SAX and DOM, two standard Java APIs

Chapter 22, takes the distributed notion one step further anddiscusses Remote Method Invocation, Java's standard remoteprocedure call mechanism RMI lets you build clients, servers,and even "callback" scenarios, using a standard Java

mechanismthe Interfaceto describe the contract between clientand server

Chapter 23, shows how to create packages of classes that worktogether This chapter also talks about "deploying" or

distributing and installing your software

Chapter 24, tells you how to write classes that appear to domore than one thing at a time and let you take advantage ofpowerful multiprocessor hardware

Sometimes you already have code written and working in

another language that can do part of your work for you, or youwant to use Java as part of a larger package Chapter 26,

shows you how to run an external program (compiled or script)and also interact directly with "native code" in C/C++ or otherlanguages

There isn't room in an 800-page book for everything I'd like totell you about Java The Chapter 27 presents some closing

thoughts and a link to my online summary of Java APIs thatevery Java developer should know about

No two programmers or writers will agree on the best order forpresenting all the Java topics To help you find your way

around, I've included extensive cross-references, mostly byrecipe number

Java has gone through five major versions The first official

release was JDK 1.0, and its last bug-fixed version was 1.0.2.The second major release is Java JDK 1.1, and the latest bug-fixed version is 1.1.9, though it may be up from that by thetime you read this book The third major release, in December

1998, was to be known as JDK 1.2, but somebody at Sun

abruptly renamed JDK 1.2 at the time of its release to Java 2,and the implementation is known as Java 2 SDK 1.2 The

current version as of the writing of the first edition of this bookwas Java 2 SDK 1.3 (JDK 1.3), which was released in 2000

As the first edition of this book went to press, Java 2 Version1.4 was about to appear; it entered beta (which Sun calls "earlyaccess") around the time of the book's completion so I couldmention it only briefly The second edition of this book looks tohave better timing; Java 2 Version 1.5 is in beta as I am

updating the book

This book is aimed at the fifth version, Java 2 Standard Edition,Version 1.5 By the time of publication, I expect that all Javaprojects in development will be using JDK 1.4, with a very fewwedded to earlier versions for historical reasons I have usedseveral platforms to test this code for portability I've testedwith Sun's Linux JDK For the mass market, I've tested many ofthe programs on Sun's Win32 (Windows 2000/XP/2003)

implementation And, "for the rest of us," I've done most of myrecent development using Apple's Mac OS X Version 10.2.x andlater However, since Java is portable, I anticipate that the vastmajority of the examples will work on any Java-enabled

platform, except where extra APIs are required Not every

example has been tested on every platform, but all have beentested on at least oneand most on more than one

The Java API consists of two parts: core APIs and noncore APIs

everything else But even this "core" is far from tiny: it weighs

in at around 50 packages and well over 2,000 public classes,averaging around 12 public methods each Programs that stick

to this core API are reasonably assured of portability to any

Java platform

The noncore APIs are further divided into standard extensionsand nonstandard extensions All standard extensions have

package names beginning with javax.[3] (and reference

implementations are available from Sun) A Java licensee (such

as Apple or IBM) is not required to implement every standardextension, but if it does, the interface of the standard extensionshould be adhered to This book calls your attention to any codethat depends on a standard extension Little code here depends

on nonstandard extensions, other than code listed in the bookitself My own package, com.darwinsys, contains some utilityclasses used here and there; you will see an import for this atthe top of any file that uses classes from it

[3] Note that not all packages named javax are extensions: javax.swing and its subpackagesthe Swing GUI packagesused to be extensions, but are now core.

In addition, two other platforms, the J2ME and the J2EE, are

standardized Java 2 Micro Edition is concerned with small

devices such as handhelds (PalmOS and others), cell phones,fax machines, and the like Within J2ME are various "profiles"for different classes of devices At the high end, the Java 2

Enterprise Edition (J2EE) is concerned with building large,

scalable, distributed applications Servlets, JavaServer Pages,JavaServer Faces, CORBA, RMI, JavaMail, Enterprise

JavaBeans© (EJBs), Transactions, and other APIs are part ofthe J2EE J2ME and J2EE packages normally begin with "javax"

as they are not core J2SE packages This book does not coverJ2ME at all but includes a few of the J2EE APIs that are alsouseful on the client side, such as RMI and JavaMail As

edition of this book has been removed as there is now a Servlet

and JSP Cookbook.

A lot of useful information is packed into this book However,due to the breadth of topics, it is not possible to give book-length treatment to any one topic Because of this, the bookalso contains references to many web sites and other books.This is in keeping with my target audience: the person whowants to learn more about Java

O'Reilly publishes, in my opinion, the best selection of Java

books on the market As the API continues to expand, so doesthe coverage You can find the latest versions and ordering

information on O'Reilly's Java books online at

http://java.oreilly.com, and you can buy them at most

bookstores, both physical and virtual You can also read themonline through a paid subscription service; see

http://safari.oreilly.com While many are mentioned at

appropriate spots in the book, a few deserve special mentionhere

Harold, and Database Programming with JDBC and Java, by

George Reese, are also useful references

date list

General Programming Books

Donald E Knuth's The Art of Computer Programming has been

a source of inspiration to generations of computing studentssince its first publication by Addison Wesley in 1968 Volume 1

be used to solve real problemsare as relevant today as theywere years ago.[4]

[4] With apologies for algorithm decisions that are less relevant today given the massive changes

in computing power now available.

Though somewhat dated now, the book The Elements of

(literally) for a generation of programmers with examples fromvarious structured programming languages Kernighan and

Plauger also wrote a pair of books, Software Tools and Software

Tools in Pascal, which demonstrated so much good advice on

programming that I used to advise all programmers to readthem However, these three books are dated now; many times Iwanted to write a follow-on book in a more modern language,

but instead defer to The Practice of Programming, Brian's

follow-onco-written with Rob Piketo the Software Tools series.

This book continues the Bell Labs (now part of Lucent) tradition

of excellence in software textbooks In Recipe 3.13, I have evenadapted one bit of code from their book

Refactoring, by Martin Fowler, covers a lot of " coding cleanups"

that can be applied to code to improve readability and

maintainability Just as the GOF book introduced new

presented in a series of small, short, readable texts led by itsdesigner, Kent Beck A good overview of all the Agile methods is

Highsmith's Agile Software Development Ecosystems The first book in the XP series is Extreme Programming Explained.

Another group of important books on methodology, covering themore traditional object-oriented design, is the UML series led by

"the Three Amigos" (Booch, Jacobson, and Rumbaugh) Their

major works are the UML User Guide, UML Process, and others.

A smaller and more approachable book in the same series is

Martin Fowler's UML Distilled.

This book uses the following conventions

Programming Conventions

I use the following terminology in this book A program means either an applet, a servlet, or an application An applet is for use in a browser A servlet is similar to an applet but for use in

a server An application is any other type of program A desktop application (a.k.a client) interacts with the user A server

program deals with a client indirectly, usually via a network

connection

The examples shown are in two varieties Those that begin withzero or more import statements, a Javadoc comment, and apublic class statement are complete examples Those that beginwith a declaration or executable statement, of course, are

excerpts However, the full versions of these excerpts have beencompiled and run, and the online source includes the full

versions

Recipes are numbered by chapter and number, so, for example,Recipe 7.5 refers to the fifth recipe in Chapter 7

Typesetting Conventions

The following typographic conventions are used in this book:

Italic

Constant width

Used in code examples to show partial or complete Javasource code program listings It is also used for class

names, method names, variable names, and other

fragments of Java code

Constant width bold

Used for user input, such as commands that you type onthe command line

This icon signifies a tip, suggestion, or general note.

This icon indicates a warning or caution.

Many programs are accompanied by an example showing them

in action, run from the command line These will usually show aprompt ending in either $ for Unix or > for Windows, depending

on which computer I was using that day Text before this

prompt character can be ignored; it will be a pathname or ahostname, again depending on the system

As mentioned earlier, I've tested all the code on at least one ofthe reference platforms, and most on several Still, there may

be platform dependencies, or even bugs, in my code or in someimportant Java implementation Please report any errors youfind, as well as your suggestions for future editions, by writingto:

bookquestions@oreilly.com

An O'Reilly web site for the book lists errata, examples, and anyadditional information You can access this page at:

http://www.oreilly.com/catalog/0596007019/

I also have a personal web site for the book:

http://javacook.darwinsys.com/

Both sites list errata and plans for future editions You'll alsofind the source code for all the Java code examples to

download; please don't waste your time typing them again! For

specific instructions, see the next section

From my web site http://javacook.darwinsys.com, just followthe Downloads link You are presented with three choices:

1 Download the entire source archive as a single large zip file.

Download individual source files, indexed alphabetically aswell as by chapter

Download the binary JAR file for the com.darwinsys.*

package needed to compile many of the other programs

Most people will choose either option 1 or 2, but anyone whowants to compile my code will need option 3 See Recipe 1.5 forinformation on using these files

Downloading the entire source archive yields a large zip file withall the files from the book (and more) This archive can be

unpacked with jar (see Recipe 23.4), the free zip program from

Info-ZIP, the commercial WinZip or PKZIP, or any compatibletool The files are organized into subdirectories by topic, withone for strings (Chapter 3), regular expressions (Chapter 4),numbers (Chapter 5), and so on The archive also contains theindex by name and index by chapter files from the downloadsite, so you can easily find the files you need

Downloading individual files is easy, too: simply follow the linkseither by file/subdirectory name or by chapter Once you seethe file you want in your browser, use File Save or the

equivalent, or just copy and paste it from the browser into aneditor or IDE

The files are updated periodically, so if there are differencesbetween what's printed in the book and what you get, be glad,

for you'll have received the benefit of hindsight.

My life has been touched many times by the flow of the fatesbringing me into contact with the right person to show me theright thing at the right time Steve Munroe, with whom I've longsince lost touch, introduced me to computersin particular anIBM 360/30 at the Toronto Board of Education that was biggerthan a living room, had 32 or 64K of memory, and had perhapsthe power of a PC/XTin 1970 Herb Kugel took me under hiswing at the University of Toronto while I was learning about thelarger IBM mainframes that came later Terry Wood and DennisSmith at the University of Toronto introduced me to mini- andmicro-computers before there was an IBM PC On evenings andweekends, the Toronto Business Club of Toastmasters

International (http://www.toastmasters.org) and Al Lambert'sCanada SCUBA School allowed me to develop my public

speaking and instructional abilities Several people at the

University of Toronto, but especially Geoffrey Collyer, taught methe features and benefits of the Unix operating system at a timewhen I was ready to learn it

Greg Davidson of UCSD taught the first Learning Tree course Iattended and welcomed me as a Learning Tree instructor Yearslater, when the Oak language was about to be released on Sun'sweb site, Greg encouraged me to write to James Gosling andfind out about it James's reply of March 29th, 1995, that thelawyers had made them rename the language to Java and that

it was "just now" available for download, is the prized first entry

in my saved Java mailbox Mike Rozek took me on as a LearningTree course author for a Unix course and two Java courses

After Mike's departure from the company, Francesco Zamboni,Julane Marx, and Jennifer Urick in turn provided product

management of these courses Jennifer also arranged

permission for me to "reuse some code" in this book that hadpreviously been used in my Java course notes Finally, thanks to