Are you looking for a deeper understanding of the Java™ programming language so that you can write code that is clearer, more correct, more robust, and more reusable? Look no further! Effective Java™, Second Edition, brings together seventy-eight indispensable programmer’s rules of thumb: working, best-practice solutions for the programming challenges you encounter every day.
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 since the 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, standalone 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.
- New coverage of generics, enums, annotations, autoboxing, the for-each loop, varargs, concurrency utilities, and much more
- Updated techniques and best practices on classic topics, including objects, classes, libraries, methods, and serialization
- How to avoid the traps and pitfalls of commonly misunderstood subtleties of the language
- Focus on the language and its most fundamental libraries: java.lang, java.util, and, to a lesser extent, java.util.concurrent and java.io
Simply put, Effective Java™, Second Edition, presents the most practical, authoritative guidelines available for writing efficient, well-designed programs.
About the Author
Joshua Bloch is chief Java architect at Google and a Jolt Award winner. He was previously a distinguished engineer at Sun Microsystems and a senior systems designer at Transarc. Bloch led the design and implementation of numerous Java platform features, including JDK 5.0 language enhancements and the award-winning Java Collections Framework. He coauthored Java™ Puzzlers (Addison-Wesley, 2005) and Java™ Concurrency in Practice (Addison-Wesley, 2006).
Table of Contents
Chapter 1: Introduction 1
Chapter 2: Creating and Destroying Objects 5
Item 1: Consider static factory methods instead of constructors 5
Item 2: Consider a builder when faced with many constructor
Item 3: Enforce the singleton property with a private constructor 17
Item 4: Enforce noninstantiability with a private constructor 19
Item 5: Avoid creating unnecessary objects 20
Item 6: Eliminate obsolete object references 24
Item 7: Avoid finalizers 27
Chapter 3: Methods Common to All Objects 33
Item 8: Obey the general contract when overriding equals 33
Item 9: Always override hashCode when you override equals 45
Item 10: Always override toString 51
Item 11: Override clone judiciously 54
Item 12: Consider implementing Comparable 62
Chapter 4: Classes and Interfaces 67
Item 13: Minimize the accessibility of classes and members 67
Item 14: In public classes, use accessor methods, not public fields 71
Item 15: Minimize mutability 73
Item 16: Favor composition over inheritance 81
Item 17: Design and document for inheritance or else prohibit it 87
Item 18: Prefer interfaces to abstract classes 93
Item 19: Use interfaces only to define types 98
Item 20: Prefer class hierarchies to tagged classes 100
Item 21: Use function objects to represent strategies 103
Item 22: Favor static member classes over nonstatic 106
Chapter 5: Generics 109
Item 23: Don't use raw types in new code 109
Item 24: Eliminate unchecked warnings 116
Item 25: Prefer lists to arrays 119
Item 26: Favor generic types 124
Item 27: Favor generic methods 129
Item 28: Use bounded wildcards to increase API flexibility 134
Item 29: Consider typesafe heterogeneous containers 142
Chapter 6: Enums and Annotations 147
Item 30: Use enums instead of int constants 147
Item 31: Use instance fields instead of ordinals 158
Item 32: Use EnumSet instead of bit fields 159
Item 33: Use EnumMap instead of ordinal indexing 161
Item 34: Emulate extensible enums with interfaces 165
Item 35: Prefer annotations to naming patterns 169
Item 36: Consistently use the Override annotation 176
Item 37: Use marker interfaces to define types 179
Chapter 7: Methods 181
Item 38: Check parameters for validity 181
Item 39: Make defensive copies when needed 184
Item 40: Design method signatures carefully 189
Item 41: Use overloading judiciously 191
Item 42: Use varargs judiciously 197
Item 43: Return empty arrays or collections, not nulls 201
Item 44: Write doc comments for all exposed API elements 203
Chapter 8: General Programming 209
Item 45: Minimize the scope of local variables 209
Item 46: Prefer for-each loops to traditional for loops 212
Item 47: Know and use the libraries 215
Item 48: Avoid float and double if exact answers are required 218
Item 49: Prefer primitive types to boxed primitives 221
Item 50: Avoid strings where other types are more appropriate 224
Item 51: Beware the performance of string concatenation 227
Item 52: Refer to objects by their interfaces 228
Item 53: Prefer interfaces to reflection 230
Item 54: Use native methods judiciously 233
Item 55: Optimize judiciously 234
Item 56: Adhere to generally accepted naming conventions 237
Chapter 9: Exceptions 241
Item 57: Use exceptions only for exceptional conditions 241
Item 58: Use checked exceptions for recoverable conditions and runtime exceptions for programming errors 244
Item 59: Avoid unnecessary use of checked exceptions 246
Item 60: Favor the use of standard exceptions 248
Item 61: Throw exceptions appropriate to the abstraction 250
Item 62: Document all exceptions thrown by each method 252
Item 63: Include failure-capture information in detail messages 254
Item 64: Strive for failure atomicity 256
Item 65: Don’t ignore exceptions 258
Chapter 10: Concurrency 259
Item 66: Synchronize access to shared mutable data 259
Item 67: Avoid excessive synchronization 265
Item 68: Prefer executors and tasks to threads 271
Item 69: Prefer concurrency utilities to wait and notify 273
Item 70: Document thread safety 278
Item 71: Use lazy initialization judiciously 282
Item 72: Don’t depend on the thread scheduler 286
Item 73: Avoid thread groups 288
Chapter 11: Serialization 289
Item 74: Implement Serializable judiciously 289
Item 75: Consider using a custom serialized form 295
Item 76: Write readObject methods defensively 302
Item 77: For instance control, prefer enum types to readResolve 309
Item 78: Consider serialization proxies instead of serialized instances 313
Appendix: Items Corresponding to First Edition 317
Index of Patterns and Idioms 327
Preface to the Second Edition
A lot has happened to the Java platform since I wrote the first edition of this book in 2001, and it’s high time for a second edition. The most significant set of changes was the addition of generics, enum types, annotations, autoboxing, and the for-each loop in Java 5. A close second was the addition of the new concurrency library, java.util.concurrent, also released in Java 5. With Gilad Bracha, I had the good fortune to lead the teams that designed the new language features. I also had the good fortune to serve on the team that designed and developed the concurrency library, which was led by Doug Lea.
The other big change in the platform is the widespread adoption of modern Integrated Development Environments (IDEs), such as Eclipse, IntelliJ IDEA, and NetBeans, and of static analysis tools, such as FindBugs. While I have not been involved in these efforts, I’ve benefited from them immensely and learned how they affect the Java development experience.
In 2004, I moved from Sun to Google, but I’ve continued my involvement in the development of the Java platform over the past four years, contributing to the concurrency and collections APIs through the good offices of Google and the Java Community Process. I’ve also had the pleasure of using the Java platform to develop libraries for use within Google. Now I know what it feels like to be a user.
As was the case in 2001 when I wrote the first edition, my primary goal is to share my experience with you so that you can imitate my successes while avoiding my failures. The new material continues to make liberal use of real-world examples from the Java platform libraries.
The first edition succeeded beyond my wildest expectations, and I’ve done my best to stay true to its spirit while covering all of the new material that was required to bring the book up to date. It was inevitable that the book would grow, and grow it did, from fifty-seven items to seventy-eight. Not only did I add twenty-three items, but I thoroughly revised all the original material and retired a few items whose better days had passed. In the Appendix, you can see how the material in this edition relates to the material in the first edition.
In the Preface to the First Edition, I wrote that the Java programming language and its libraries were immensely conducive to quality and productivity, and a joy to work with. The changes in releases 5 and 6 have taken a good thing and made it better. The platform is much bigger now than it was in 2001 and more complex, but once you learn the patterns and idioms for using the new features, they make your programs better and your life easier. I hope this edition captures my continued enthusiasm for the platform and helps make your use of the platform and its new features more effective and enjoyable.
San Jose, California
Most Helpful Customer Reviews
This book not only provides gems of advice for core Java programming but also for programming in general, especially if your code will be provided as an API to other programmers and if it is going to live for more than a few months. Another interesting aspect of the book is that the more I contemplate upon it, the more it resembles like advocacy for functional programming. At least some parts really made me think like "hmm, that would be considered natural in Scala" (insert your favorite functional programming language here, even if it's not purely functional in the strictest academic sense). The book is also helpful if you've spent long time in high level languages such as Python or Lisp before coming to Java, and are curious about how you can get an approximation of some of their good parts such as optional named arguments. The foreword of Guy L. Steele, Jr. says it all: after learning the vocabulary and grammar of a language you need to master the pragmatics of it rooted in real life cases so that your communication with other language speakers will smooth flowly. Bloch's book helps you with that effectively and I think every programming language deserves at least one author of Bloch's calibre.
Joshua Bloch, once a developer for Sun (and in fact one of the primary authors of the Java Collections API), guides you through a series of enlightening "Dos and Don'ts" about the Java programming language. The book is broken up into short items, with each item containing evidence, examples, and a good conversational explanation of the item. It's a great deal thinner than its C-language counterpart, but don't let that dissuade you from the purchase; Bloch will save you a ton of time reading through the JLS, or learning these lessons the hard way. I keep a copy in my work desk for reference, and even if you've been programming Java for years, it's likely you'll learn something.
Very useful, very insightful.