Effective Java¿ Programming Language Guide

by Bloch, Joshua

• ISBN13: 9780201310054
• ISBN10: 0201310058
• Edition: 1st
• Format: Paperback
• Copyright: 2001-01-01
• Publisher: Prentice Hall

Summary

"This highly anticipated new edition of the classic, Jolt Award-winning work has been thoroughly updated to cover Java SE 5 and Java SE 6 features introduced sincethe first edition. Bloch explores new design patterns and language idioms, showing you how to make the most of features ranging from generics to enums, annotations to autoboxing." "Each chapter in the book consists of several "items" presented in the form of a short, stand alone essay that provides specific advice, insight into Java platform subtleties, and outstanding code examples. The comprehensive descriptions and explanations for each item illuminate what to do, what not to do, and why."--BOOK JACKET.

Table of Contents

Foreword	xi
Preface	xiii
Acknowledgments	xv
Introduction	1	(4)
Creating and Destroying Objects	5	(20)
Consider providing static factory methods instead of constructors	5	(5)
Enforce the singleton property with a private constructor	10	(2)
Enforce noninstantiability with a private constructor	12	(1)
Avoid creating duplicate objects	13	(4)
Eliminate obsolete object references	17	(3)
Avoid finalizers	20	(5)
Methods Common to All Objects	25	(34)
Obey the general contract when overriding equals	25	(11)
Always override hashCode when you override equals	36	(6)
Always override to String	42	(3)
Override clone judiciously	45	(8)
Consider implementing Comparable	53	(6)
Classes and Interfaces	59	(38)
Minimize the accessibility of classes and members	59	(4)
Favor immutability	63	(8)
Favor composition over inheritance	71	(7)
Design and document for inheritance or else prohibit it	78	(6)
Prefer interfaces to abstract classes	84	(5)
Use interfaces only to define types	89	(2)
Favor static member classes over nonstatic	91	(6)
Substitutes for C Constructs	97	(22)
Replace structures with classes	97	(3)
Replace unions with class hierarchies	100	(4)
Replace enum constructs with classes	104	(11)
Replace function pointers with classes and interfaces	115	(4)
Methods	119	(22)
Check parameters for validity	119	(3)
Make defensive copies when needed	122	(4)
Design method signatures carefully	126	(2)
Use overloading judiciously	128	(6)
Return zero-length arrays, not nulls	134	(2)
Write doc comments for all exposed API elements	136	(5)
General Programming	141	(28)
Minimize the scope of local variables	141	(4)
Know and use the libraries	145	(4)
Avoid float and double if exact answers are required	149	(3)
Avoid strings where other types are more appropriate	152	(3)
Beware the performance of string concatenation	155	(1)
Refer to objects by their interfaces	156	(2)
Prefer interfaces to reflection	158	(3)
Use native methods judiciously	161	(1)
Optimize judiciously	162	(3)
Adhere to generally accepted naming conventions	165	(4)
Exceptions	169	(20)
Use exceptions only for exceptional conditions	169	(3)
Use checked exceptions for recoverable conditions and run-time exceptions for programming errors	172	(2)
Avoid unnecessary use of checked exceptions	174	(2)
Favor the use of standard exceptions	176	(2)
Throw exceptions appropriate to the abstraction	178	(3)
Document all exceptions thrown by each method	181	(2)
Include failure-capture information in detail messages	183	(2)
Strive for failure atomicity	185	(2)
Don't ignore exceptions	187	(2)
Threads	189	(24)
Synchronize access to shared mutable data	189	(7)
Avoid excessive synchronization	196	(5)
Never invoke wait outside a loop	201	(3)
Don't depend on the thread scheduler	204	(4)
Document thread safety	208	(3)
Avoid thread groups	211	(2)
Serialization	213	(20)
Implement Serializable judiciously	213	(5)
Consider using a custom serialized form	218	(6)
Write readObject methods defensively	224	(6)
Provide a readResolve method when necessary	230	(3)
References	233	(6)
Index of Patterns and Idioms	239	(2)
Index	241

Excerpts

In 1996 I pulled up stakes and headed west to work for JavaSoft, as it was then known, because it was clear that was where the action was. In the intervening five years I've served as Java Platform Libraries Architect. I've designed, implemented and maintained many of the libraries, and served as a consultant for many others. Presiding over these libraries as the Java platform matured was a once-in-a-lifetime opportunity. It is no exaggeration to say that I had the privilege to work with some of the great software engineers of our generation. In the process, I learned a lot about the Java programming language--what works, what doesn't, and how to use the language and its libraries to best effect. This book is my attempt to share my experience with you, so that you can imitate my successes while avoiding my failures. I borrowed the format from Scott Meyers's Effective C++ Meyers98, which consists of fifty items, each conveying one specific rule for improving your programs and designs. I found the format to be singularly effective and I hope you do too. In many cases, I took the liberty of illustrating the items with real-world examples from the Java platform libraries. When describing something that could have been done better, I tried to pick on code that I wrote myself, but occasionally I pick on something written by a colleague. I sincerely apologize if, despite my best efforts, I've offended anyone. Negative examples are cited not to cast blame but in the spirit of cooperation, so that all of us can benefit from the experience of those who've gone before. While this book is not targeted solely at developers of reusable components, it is inevitably colored by my experience writing such components over the past two decades. I naturally think in terms of exported APIs (Application Programming Interfaces) and I encourage you to do likewise. Even if you aren't developing reusable components, thinking in these terms tends to improve the quality of the software you write. Furthermore, it's not uncommon to write a reusable component without knowing it: you write something useful, share it with your buddy across the hall, and before long you have half a dozen users. At this point, you no longer have the flexibility to change the API at will, and are thankful for all the effort that you put into designing the API when you first wrote the software. My focus on API design may seem a bit unnatural to devotees of the new lightweight software development methodologies, such as Extreme Programming Explained Beck99. These methodologies emphasize writing the simplest program that could possibly work. If you're using one of these methodologies you'll find that a focus on API design serves you well in the refactoring process. The fundamental goals of refactoring are the improvement of system structure and the avoidance of code duplication. These goals are impossible to achieve in the absence of well-designed APIs for the components of the system. No language is perfect, but some of them are excellent. I have found the Java programming language and its libraries to be immensely conducive to quality and productivity, and a joy to work with. I hope this book captures my enthusiasm and helps make your use of the language more effective and enjoyable. Josh Bloch Cupertino, California April, 2001 0201310058P04232001