book

Java 5.0 Tiger: A Developer's Notebook

by Brett McLaughlin, David Flanagan

June 2004

Intermediate to advanced

202 pages

4h 31m

English

O'Reilly Media, Inc.

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A Note Regarding Supplemental Files
Copyright
The Developer’s Notebook Series
Notebooks Are...Notebooks Aren’t...Organization
Preface
OrganizationHow This Book Was WrittenAbout the ExamplesConventions Used in This BookHow to Contact UsAcknowledgments from BrettAcknowledgments from David
1. What’s New?
1.1. Working with Arrays1.1.1. How do I do that?1.1.2. What About...1.2. Using Queues1.2.1. How do I do that?1.2.2. What about...1.3. Ordering Queues Using Comparators1.3.1. How do I do that?1.4. Overriding Return Types1.4.1. How do I do that?1.5. Taking Advantage of Better Unicode1.5.1. How do I do that?1.5.2. What just happened?1.6. Adding StringBuilder to the Mix1.6.1. How do I do that?1.6.2. What about...
2. Generics
2.1. Using Type-Safe Lists2.1.1. How do I do that?2.1.2. What just happened?2.1.3. What about...2.2. Using Type-Safe Maps2.2.1. How do I do that?2.2.2. What just happened?2.3. Iterating Over Parameterized Types2.3.1. How do I do that?2.3.2. What about...2.4. Accepting Parameterized Types as Arguments2.4.1. How do I do that?2.4.2. What about...2.5. Returning Parameterized Types2.5.1. How do I do that?2.6. Using Parameterized Types as Type Parameters2.6.1. How do I do that?2.7. Checking for Lint2.7.1. How do I do that?2.7.2. What about...2.8. Generics and Type Conversions2.8.1. How do I do that?2.8.2. What just happened?2.8.3. What about...2.9. Using Type Wildcards2.9.1. How do I do that?2.9.2. What about...2.10. Writing Generic Types2.10.1. How do I do that?2.10.2. What about...2.11. Restricting Type Parameters2.11.1. How do I do that?2.11.2. What about...
3. Enumerated Types
3.1. Creating an Enum3.1.1. How do I do that?3.1.2. What just happened?3.1.3. What about...3.2. Declaring Enums Inline3.2.1. How do I do that?3.3. Iterating Over Enums3.3.1. How do I do that?3.3.2. What just happened?3.3.3. What about...3.4. Switching on Enums3.4.1. How do I do that?3.4.2. What just happened?3.4.3. What about...3.5. Maps of Enums3.5.1. How do I do that?3.6. Sets of Enums3.6.1. How do I do that?3.7. Adding Methods to an Enum3.7.1. How do I do that?3.7.2. What about...3.8. Implementing Interfaces with Enums3.8.1. How do I do that?3.9. Value-Specific Class Bodies3.9.1. How do I do that?3.9.2. What just happened?3.9.3. What about...3.10. Manually Defining an Enum3.10.1. How do I do that?3.11. Extending an Enum3.11.1. How do I do that?3.11.2. What about...
4. Autoboxing and Unboxing
4.1. Converting Primitives to Wrapper Types4.1.1. How do I do that?4.1.2. What just happened?4.2. Converting Wrapper Types to Primitives4.2.1. How do I do that?4.2.2. What about...4.3. Incrementing and Decrementing Wrapper Types4.3.1. How do I do that?4.3.2. What just happened?4.4. Boolean Versus boolean4.4.1. How do I do that?4.4.2. What about...4.5. Conditionals and Unboxing4.5.1. How do I do that?4.5.2. What just happened?4.6. Control Statements and Unboxing4.6.1. How do I do that?4.7. Method Overload Resolution4.7.1. How do I do that?4.7.2. What just happened?
5. varargs
5.1. Creating a Variable-Length Argument List5.1.1. How do I do that?5.1.2. What just happened?5.1.3. What about...5.2. Iterating Over Variable-Length Argument Lists5.2.1. How do I do that?5.2.2. What about...5.3. Allowing Zero-Length Argument Lists5.3.1. How do I do that?5.3.2. What about...5.4. Specify Object Arguments Over Primitives5.4.1. How do I do that?5.5. Avoiding Automatic Array Conversion5.5.1. How do I do that?
6. Annotations
6.1. Using Standard Annotation Types6.1.1. How do I do that?6.1.2. What just happened?6.1.3. What about...6.2. Annotating an Overriding Method6.2.1. How do I do that?6.2.2. What about...6.3. Annotating a Deprecated Method6.3.1. How do I do that?6.3.2. What about...6.4. Suppressing Warnings6.4.1. How do I do that?6.5. Creating Custom Annotation Types6.5.1. How do I do that?6.5.2. What about...6.6. Annotating Annotations6.6.1. How do I do that?6.7. Defining an Annotation Type’s Target6.7.1. How do I do that?6.7.2. What about...6.8. Setting the Retention of an Annotation Type6.8.1. How do I do that?6.9. Documenting Annotation Types6.9.1. How do I do that?6.10. Setting Up Inheritance in Annotations6.10.1. How do I do that?6.10.2. What about...6.11. Reflecting on Annotations6.11.1. How do I do that?6.11.2. What just happened?6.11.3. What about...

7. The for/in Statement
7.1. Ditching Iterators7.1.1. How do I do that?7.1.2. What just happened?7.1.3. What about...7.2. Iterating over Arrays7.2.1. How do I do that?7.2.2. What about...7.3. Iterating over Collections7.3.1. How do I do that?7.4. Avoiding Unnecessary Typecasts7.4.1. How do I do that?7.4.2. What just happened?7.5. Making Your Classes Work with for/in7.5.1. How do I do that?7.5.1.1. Extending collection classes7.5.1.2. Handling iteration manually7.6. Determining List Position and Variable Value7.6.1. How do I do that?7.7. Removing List Items in a for/in Loop7.7.1. How do I do that?7.7.2. What about...
8. Static Imports
8.1. Importing Static Members8.1.1. How do I do that?8.1.2. What about...8.2. Using Wildcards in Static Imports8.2.1. How do I do that?8.2.2. What about...8.3. Importing Enumerated Type Values8.3.1. How do I do that?8.4. Importing Multiple Members with the Same Name8.4.1. How do I do that?8.4.2. What about...8.5. Shadowing Static Imports8.5.1. How do I do that?
9. Formatting
9.1. Creating a Formatter9.1.1. How do I do that?9.2. Writing Formatted Output9.2.1. How do I do that?9.2.1.1. Types9.2.1.2. Precision9.2.1.3. Width9.2.1.4. Argument9.2.1.5. Flags9.2.1.6. Output9.3. Using the format( ) Convenience Method9.3.1. How do I do that?9.4. Using the printf( ) Convenience Method9.4.1. How do I do that?
10. Threading
10.1. Handling Uncaught Exceptions in Threads10.1.1. How do I do that?10.1.2. What about...10.2. Using Thread-Safe Collections10.2.1. How do I do that?10.2.1.1. ConcurrentHashMap10.2.1.2. CopyOnWriteArrayList10.2.1.3. CopyOnWriteArraySet10.2.2. What just happened?10.2.3. What about...10.3. Using Blocking Queues10.3.1. How do I do that?10.4. Specifying Timeouts for Blocking10.4.1. How do I do that?10.4.2. What about...10.5. Separating Thread Logic from Execution Logic10.5.1. How do I do that?10.5.2. How do I do that?10.5.3. What about...10.6. Using Executor as a Service10.6.1. How do I do that?10.7. Using Callable Objects10.7.1. How do I do that?10.8. Executing Tasks Without an ExecutorService10.8.1. How do I do that?10.8.2. What about...10.9. Scheduling Tasks10.9.1. How do I do that?10.9.2. What about...10.10. Advanced Synchronizing10.10.1. How do I do that?10.11. Using Atomic Types10.11.1. How do I do that?10.11.2. What about...10.12. Locking Versus Synchronization10.12.1. How do I do that?10.12.2. What about...
Index
About the Authors
Colophon
Copyright

Content preview from Java 5.0 Tiger: A Developer's Notebook

Chapter 4. Autoboxing and Unboxing

Note

In this chapter:

When you begin to study Java, one of the first lessons is always about objects. In fact, you could say that java.lang.Object is the very cornerstone of Java. Practically 99% of everything you do in the language revolves around that class, or one of its subclasses. It’s the 1% of the time, though, that can be a pain—when you suddenly find yourself having to convert between your objects and Java primitives.

Primitives in Java are your ints, shorts, chars, and so on—types that aren’t objects at all. As a result, Java has wrapper classes, such as Integer, Short, and Character, which are object versions of the primitive types. Where things get annoying is when you have to go back and forth between the two—converting a primitive to its wrapper, using it, then converting the object’s value back to a primitive. Suddenly, methods such as intValue( ) begin to litter your code.

Happily, Tiger finally takes care of this issue, at least as much as can be expected without tossing out primitives completely. This is handled through two new conversion features: boxing and unboxing. And, just to add some more words to the English language, it does these conversions automatically, so we now talk about autoboxing ...

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Java 5.0 Tiger: A Developer's Notebook

by Brett McLaughlin, David Flanagan

Chapter 4. Autoboxing and Unboxing

Note

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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