On Java 8
On Java 8
About the Book
This book teaches Java programming using the features in the 8th version of that language.
My previous Java book, Thinking in Java, 4th Edition (Prentice Hall 2006), is still useful for programming in Java 5, the version of the language used for Android programming. But especially with the advent of Java 8, the language has changed significantly enough that new Java code feels and reads differently. This justified the two-year effort of creating a new book.
Each chapter teaches a concept, or a group of associated concepts, without relying on features that haven't yet been introduced. That way you can digest each piece in the context of your current knowledge before moving on.
My goals in this book are to:
1. Present the material one step at a time so you can easily incorporate each idea before moving on, and to carefully sequence the presentation of features so you're exposed to a topic before you see it in use. This isn't always possible; in those situations, a brief introductory description is given.
2. Use examples that are as simple and short as possible. This sometimes prevents me from tackling "real world" problems, but I've found that beginners are usually happier when they can understand every detail of an example rather than being impressed by the scope of the problem it solves. For this I might receive criticism for using "toy examples," but I'm willing to accept that in favor of producing something pedagogically useful.
3. Give you what I think is important for you to understand about the language, rather than everything I know. I believe there is an information importance hierarchy, and there are some facts that 95 percent of programmers will never need to know---details that just confuse people and increase their perception of the complexity of the language. If you must think about it, it will also confuse the reader/maintainer of that code, so I advocate choosing a simpler approach.
4. Provide you with a solid foundation so you understand the issues well enough to move on to more difficult coursework and books.
About the Author
Table of Contents
- Copyright
-
Foreword to the Leanpub Edition
- Updates
- January 2021 Update
- March 2021 Update
-
Preface
- Goals
- Language Design Errors
- Tested Examples
- Popularity
- Android Programmers
- This is Only an eBook
- Colophon
- Thanks
- Dedication
-
Introduction
- Prerequisites
- JDK HTML Documentation
- Thinking in C
- Source Code
- Coding Standards
- Bug Reports
- What About User Interfaces?
-
What is an Object?
- The Progress of Abstraction
- An Object Has an Interface
- Objects Provide Services
- The Hidden Implementation
- Reusing the Implementation
- Inheritance
- Interchangeable Objects with Polymorphism
- The Singly-Rooted Hierarchy
- Collections
- Object Creation & Lifetime
- Exception Handling: Dealing with Errors
- Summary
-
Installing Java and the Book Examples
- Editors
- The Shell
- Installing Java
- Verify Your Installation
- Installing and Running the Book Examples
-
Objects Everywhere
- You Manipulate Objects with References
- You Must Create All the Objects
- Comments
- You Never Need to Destroy an Object
-
Creating New Data Types:
class - Methods, Arguments, and Return Values
- Writing a Java Program
- Your First Java Program
- Coding Style
- Summary
-
Operators
- Using Java Operators
- Precedence
- Assignment
- Mathematical Operators
- Auto Increment and Decrement
- Relational Operators
- Logical Operators
- Literals
- Bitwise Operators
- Shift Operators
-
Ternary
if-elseOperator -
StringOperator + and += - Common Pitfalls When Using Operators
- Casting Operators
- Java Has No “sizeof”
- A Compendium of Operators
- Summary
-
Control Flow
-
trueandfalse -
if-else - Iteration Statements
- For-in Syntax
-
return -
breakandcontinue - The Infamous “Goto”
-
switch - Switching on Strings
- Summary
-
-
Housekeeping
- Guaranteed Initialization with the Constructor
- Method Overloading
- Zero-Argument Constructors
-
The
thisKeyword - Cleanup: Finalization and Garbage Collection
- Member Initialization
- Constructor Initialization
- Array Initialization
- Enumerated Types
- Summary
-
Implementation Hiding
-
package: the Library Unit - Java Access Specifiers
- Interface and Implementation
- Class Access
- Summary
-
-
Reuse
- Composition Syntax
- Inheritance Syntax
- Delegation
- Combining Composition and Inheritance
- Choosing Composition vs. Inheritance
-
protected - Upcasting
-
The
finalKeyword - Initialization and Class Loading
- Summary
-
Polymorphism
- Upcasting Revisited
- The Twist
- Constructors and Polymorphism
- Covariant Return Types
- Designing with Inheritance
- Summary
-
Interfaces
- Abstract Classes and Methods
- Defining Interfaces
- Abstract Classes vs. Interfaces
- Complete Decoupling
- Combining Multiple Interfaces
- Extending an Interface with Inheritance
- Adapting to an Interface
- Fields in Interfaces
- Nesting Interfaces
- Interfaces and Factories
- Summary
-
Inner Classes
- Creating Inner Classes
- The Link to the Outer Class
-
Using
.thisand.new - Inner Classes and Upcasting
- Inner Classes in Methods and Scopes
- Anonymous Inner Classes
- Nested Classes
- Why Inner Classes?
- Inheriting from Inner Classes
- Can Inner Classes Be Overridden?
- Local Inner Classes
- Inner-Class Identifiers
- Summary
-
Collections
- Generics and Type-Safe Collections
- Basic Concepts
- Adding Groups of Elements
- Printing Collections
-
List -
Iterators -
LinkedList -
Stack -
Set -
Map -
Queue -
Collectionvs.Iterator - for-in and Iterators
- Summary
-
Functional Programming
- Old vs. New
- Lambda Expressions
- Method References
- Functional Interfaces
- Higher-Order Functions
- Closures
- Function Composition
- Currying and Partial Evaluation
- Pure Functional Programming
- Summary
-
Streams
- Java 8 Stream Support
- Stream Creation
- Intermediate Operations
- Optional
- Terminal Operations
- Summary
-
Exceptions
- Concepts
- Basic Exceptions
- Catching an Exception
- Creating Your Own Exceptions
- The Exception Specification
- Catching Any Exception
- Standard Java Exceptions
-
Performing Cleanup with
finally - Exception Restrictions
- Constructors
- Try-With-Resources
- Exception Matching
- Alternative Approaches
- Exception Guidelines
- Summary
-
Validating Your Code
- Testing
- Preconditions
- Test-Driven Development
- Logging
- Debugging
- Benchmarking
- Profiling and Optimizing
- Style Checking
- Static Error Analysis
- Code Reviews
- Pair Programming
- Refactoring
- Continuous Integration
- Summary
-
Files
- File and Directory Paths
- Directories
- File Systems
-
Watching a
Path - Finding Files
- Reading & Writing Files
- Summary
-
Strings
-
Immutable
Strings -
Overloading
+vs.StringBuilder - Unintended Recursion
-
Operations on
Strings - Formatting Output
- Regular Expressions
- Scanning Input
-
StringTokenizer - Summary
-
Immutable
-
Reflection
- The Need for Reflection
-
The
ClassObject - Checking Before a Cast
- Registered Factories
-
Instanceofvs.ClassEquivalence - Runtime Class Information
- Dynamic Proxies
- Using Optional
- Interfaces and Type Information
- Summary
-
Generics
- Comparison with C++
- Simple Generics
- Generic Interfaces
- Generic Methods
- Building Complex Models
- The Mystery of Erasure
- Compensating for Erasure
- Bounds
- Wildcards
- Issues
- Self-Bounded Types
- Dynamic Type Safety
- Exceptions
- Mixins
- Latent Typing
- Compensating for the Lack of (Direct) Latent Typing
- Assisted Latent Typing in Java 8
- Summary: Is Casting Really So Bad?
-
Arrays
- Why Arrays are Special
- Arrays are First-Class Objects
- Returning an Array
- Multidimensional Arrays
- Arrays and Generics
-
Arrays.fill() -
Arrays.setAll() - Incremental Generators
- Random Generators
- Generics and Primitive Arrays
- Modifying Existing Array Elements
- An Aside On Parallelism
-
ArraysUtilities - Copying an Array
- Comparing Arrays
-
Streams and Arrays - Sorting Arrays
-
Searching with
Arrays.binarySearch() -
Accumulating with
parallelPrefix() - Summary
-
Enumerations
-
Basic
enumFeatures -
Adding Methods to an
enum -
enums inswitchStatements -
The Mystery of
values() - Implements, not Inherits
- Random Selection
- Using Interfaces for Organization
-
Using
EnumSetInstead of Flags -
Using
EnumMap - Constant-Specific Methods
- Multiple Dispatching
- Summary
-
Basic
-
Annotations
- Basic Syntax
- Writing Annotation Processors
-
Using
javacto Process Annotations - Annotation-Based Unit Testing
- Summary
-
Concurrent Programming
- The Terminology Problem
- Concurrency Superpowers
- Concurrency is for Speed
- The Four Maxims of Java Concurrency
- The Brutal Truth
- The Rest of the Chapter
- Parallel Streams
- Creating and Running Tasks
- Terminating Long-Running Tasks
-
CompletableFutures - Deadlock
- Constructors are not Thread-Safe
- Effort, Complexity, Cost
- Summary
-
Patterns
- The Pattern Concept
- Singleton
- Classifying Patterns
- Template Method
- Fronting for an Implementation
- Factories: Encapsulating Object Creation
- Function Objects
- Changing the Interface
- Interpreter: Run-Time Flexibility
- Callbacks
- Multiple Dispatching
- Pattern Refactoring
- Summary
-
Appendix: Supplements
- On Java 8 Example Code
- Thinking in C: Foundations for Java
- Hands-On Java eSeminar
-
Appendix: Programming Guidelines
- Design
- Implementation
-
Appendix: Javadoc
- Syntax
- Embedded HTML
- Some Example Tags
- Documentation Example
-
Appendix: Passing and Returning Objects
- Passing References
- Making Local Copies
- Controlling Cloneability
- Immutable Classes
- Summary
-
Appendix: I/O Streams
-
Types of
InputStream -
Types of
OutputStream - Adding Attributes and Useful Interfaces
-
Readers &Writers -
Off By Itself:
RandomAccessFile - Typical Uses of I/O Streams
- Summary
-
Types of
-
Appendix: Standard I/O
- Reading from Standard Input
-
Changing
System.outto aPrintWriter - Redirecting Standard I/O
- Process Control
-
Appendix: New I/O
-
ByteBuffers - Converting Data
- Fetching Primitives
- View Buffers
- Data Manipulation with Buffers
- Memory-Mapped Files
- File Locking
-
-
Appendix: Understanding
equals()andhashCode()-
A Canonical
equals() - Hashing and Hash Codes
-
Tuning a
HashMap
-
A Canonical
-
Appendix: Collection Topics
- Sample Data
-
ListBehavior -
SetBehavior -
Using Functional Operations with any
Map -
Selecting Parts of a
Map - Filling Collections
-
Custom
CollectionandMapusing Flyweight -
CollectionFunctionality - Optional Operations
-
Sets and Storage Order - Queues
-
Understanding
Maps - Utilities
- Holding References
- Java 1.0/1.1 Collections
- Summary
-
Appendix: Low-Level Concurrency
- What is a Thread?
- Catching Exceptions
- Sharing Resources
-
The
volatileKeyword - Atomicity
- Critical Sections
- Library Components
- Summary
-
Appendix: Data Compression
- Simple Compression with GZIP
- Multifile Storage with Zip
- Java Archives (Jars)
-
Appendix: Object Serialization
- Finding the Class
- Controlling Serialization
- Using Persistence
-
Appendix: Benefits and Costs of Static Type Checking
- Foreword to the 2021 Edition
- Foreword to the Original Edition
- Static Type Checking vs. Testing
- How to Argue about Typing
- The Cost of Productivity
- Static vs. Dynamic
- Appendix: The Positive Legacy of C++ and Java
-
Appendix: Becoming a Programmer
- How I Got Started in Programming
- A Career in Computing
- The Mythical 5%
- Writing Software Is Like … Writing
- Programming as Typing
- Do What You Love
- Notes
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