On Java 8
On Java 8
About the Book
This book teaches Java programming using the features in the 8th version of that language. Version 2 of the book (December 2021) adds supplements covering features through Java 17.
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.
Table of Contents
- Copyright
-
Preface
- Post-Java-8 Features in this Book
- This is Only an eBook
- Colophon
- Acknowledgements
- Dedication
-
Introduction
- Goals
- Language Design Errors
- Popularity
- Android Programmers
- Book Updates
- The New Java “Release Cadence”
- What About User Interfaces?
- JDK HTML Documentation
- Tested Examples
- Coding Standards
- Bug Reports
- Source Code
-
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-else
Operator -
String
Operator + and += - Common Pitfalls When Using Operators
- Casting Operators
- Java Has No “sizeof”
- A Compendium of Operators
- Summary
-
Control Flow
-
true
andfalse
-
if-else
- Iteration Statements
- For-in Syntax
-
return
-
break
andcontinue
- The Infamous “Goto”
-
switch
- Switching on Strings
- Summary
-
-
Housekeeping
- Guaranteed Initialization with the Constructor
- Method Overloading
- Zero-Argument Constructors
-
The
this
Keyword - Cleanup: Finalization and Garbage Collection
- Member Initialization
- Constructor Initialization
- Array Initialization
- Enumerated Types
- New Feature: Local Variable Type Inference
- Summary
-
Implementation Hiding
-
package
: the Library Unit - Java Access Specifiers
- Interface and Implementation
- Class Access
- New Feature: Modules
- Summary
-
-
Reuse
- Composition Syntax
- Inheritance Syntax
- Delegation
- Combining Composition and Inheritance
- Choosing Composition vs. Inheritance
-
protected
- Upcasting
-
The
final
Keyword - 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
-
New Feature:
private
Methods in Interfaces - New Feature: Sealed Classes and Interfaces
- Summary
-
Inner Classes
- Creating Inner Classes
- The Link to the Outer Class
-
Using
.this
and.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
-
Iterator
s -
LinkedList
-
Stack
-
Set
-
Map
- New Feature: Records
-
Queue
-
Collection
vs.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
-
New Feature: Better
NullPointerException
Reporting -
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
String
s -
Overloading
+
vs.StringBuilder
- Unintended Recursion
-
Operations on
String
s - Formatting Output
- New Feature: Text Blocks
- Regular Expressions
- Scanning Input
-
StringTokenizer
- Summary
-
Immutable
-
Reflection
- The Need for Reflection
-
The
Class
Object - Checking Before a Cast
- Registered Factories
-
Instanceof
vs.Class
Equivalence - 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
-
Arrays
Utilities - Copying an Array
- Comparing Arrays
-
Stream
s and Arrays - Sorting Arrays
-
Searching with
Arrays.binarySearch()
-
Accumulating with
parallelPrefix()
- Summary
-
Enumerations
-
Basic
enum
Features -
Adding Methods to an
enum
-
enum
s inswitch
Statements -
The Mystery of
values()
- Implements, not Inherits
- Random Selection
- Using Interfaces for Organization
-
Using
EnumSet
Instead of Flags -
Using
EnumMap
- Constant-Specific Methods
- Multiple Dispatching
- New Features to Support Pattern Matching
-
New Feature: Arrow in
switch
-
New Feature:
case null
inswitch
-
New Feature:
switch
as an Expression - New Feature: Smart Casts
- New Feature: Pattern Matching
- Summary
-
Basic
-
Annotations
- Basic Syntax
- Writing Annotation Processors
-
Using
javac
to 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
-
CompletableFuture
s - 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: Runtime Flexibility
- Callbacks
- Multiple Dispatching
- Pattern Refactoring
- Summary
-
Appendix: Supplements
- On Java 8 Example Code
- 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
-
Reader
s &Writer
s -
Off By Itself:
RandomAccessFile
- Typical Uses of I/O Streams
- Summary
-
Types of
-
Appendix: Standard I/O
- Reading from Standard Input
-
Changing
System.out
to aPrintWriter
- Redirecting Standard I/O
- Process Control
-
Appendix: New I/O
-
ByteBuffer
s - 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
-
List
Behavior -
Set
Behavior -
Using Functional Operations with any
Map
-
Selecting Parts of a
Map
- Filling Collections
-
Custom
Collection
andMap
using Flyweight -
Collection
Functionality - Optional Operations
-
Set
s and Storage Order - Queues
-
Understanding
Map
s - Utilities
- Holding References
- Java 1.0/1.1 Collections
- Summary
-
Appendix: Low-Level Concurrency
- What is a Thread?
- Catching Exceptions
- Sharing Resources
-
The
volatile
Keyword - Atomicity
- Critical Sections
- Library Components
- Summary
-
Appendix: Data Compression
- Simple Compression with GZIP
- Multifile Storage with Zip
- Java Archives (Jars)
-
Appendix: Object Serialization
- Overview
- 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
Other books by this author
The Leanpub 60-day 100% Happiness Guarantee
Within 60 days of purchase you can get a 100% refund on any Leanpub purchase, in two clicks.
See full terms
80% Royalties. Earn $16 on a $20 book.
We pay 80% royalties. That's not a typo: you earn $16 on a $20 sale. If we sell 5000 non-refunded copies of your book or course for $20, you'll earn $80,000.
(Yes, some authors have already earned much more than that on Leanpub.)
In fact, authors have earned$12,307,240writing, publishing and selling on Leanpub.
Learn more about writing on Leanpub
Free Updates. DRM Free.
If you buy a Leanpub book, you get free updates for as long as the author updates the book! Many authors use Leanpub to publish their books in-progress, while they are writing them. All readers get free updates, regardless of when they bought the book or how much they paid (including free).
Most Leanpub books are available in PDF (for computers) and EPUB (for phones, tablets and Kindle). The formats that a book includes are shown at the top right corner of this page.
Finally, Leanpub books don't have any DRM copy-protection nonsense, so you can easily read them on any supported device.
Learn more about Leanpub's ebook formats and where to read them
Top Books
OpenIntro Statistics
David Diez, Christopher Barr, Mine Cetinkaya-Rundel, and OpenIntroA complete foundation for Statistics, also serving as a foundation for Data Science.
Leanpub revenue supports OpenIntro (US-based nonprofit) so we can provide free desk copies to teachers interested in using OpenIntro Statistics in the classroom and expand the project to support free textbooks in other subjects.
More resources: openintro.org.
Personal Finance
Jason AndersonThis textbook provides an in-depth analysis on personal finance that is both practical and straightforward in its approach. It has been written in such a way that the readers can gain knowledge without getting overwhelmed by the technical terms. Suitable for both beginners and advanced learners.
Getting to Know IntelliJ IDEA
Trisha Gee and Helen ScottIf we treat our IDE as a text editor, we are doing ourselves a disservice. Using a combination of tutorials and a questions-and-answers approach, Getting to Know IntelliJ IDEA will help you find ways to use IntelliJ IDEA that enable you to work comfortably and productively as a professional developer.
C++20 - The Complete Guide
Nicolai M. JosuttisAll new language and library features of C++20 (for those who know previous C++ versions).
The book presents all new language and library features of C++20. Learn how this impacts day-to-day programming, to benefit in practice, to combine new features, and to avoid all new traps.
Buy early, pay less, free updates.
Other books:
Mastering STM32 - Second Edition
Carmine NovielloWith more than 1200 microcontrollers, STM32 is probably the most complete ARM Cortex-M platform on the market. This book aims to be the most complete guide around introducing the reader to this exciting MCU portfolio from ST Microelectronics and its official CubeHAL and STM32CubeIDE development environment.
R Programming for Data Science
Roger D. PengThis book brings the fundamentals of R programming to you, using the same material developed as part of the industry-leading Johns Hopkins Data Science Specialization. The skills taught in this book will lay the foundation for you to begin your journey learning data science. Printed copies of this book are available through Lulu.
Machine Learning Q and AI
Sebastian Raschka, PhDHave you recently completed a machine learning or deep learning course and wondered what to learn next? With 30 questions and answers on key concepts in machine learning and AI, this book provides bite-sized bits of knowledge for your journey to becoming a machine learning expert.
Stats One
William FooteThe Rails 7 Way
Obie Fernandez, Lucas Dohmen, and Tom Henrik AadlandThe Rails™ 7 Way is the comprehensive, authoritative reference guide for professionals delivering production-quality code using modern Ruby on Rails. It illuminates the entire Rails 7 API, its most powerful idioms, design approaches, and libraries. Building on the previous editions, this edition has been heavily refactored and updated.
Gradual Modularization for Ruby and Rails
Stephan HagemannGet yourself a new tool to manage your Rails application and your growing engineering organization! Prevent the ball-of-mud (and fix it!). Go for microservices or SOA if it makes sense not just because you don't have any other tool. Do all this through a low-overhead tool: packages. Enable better conversations to make practical changes today.
Top Bundles
- #1
Software Architecture
2 Books
"Software Architecture for Developers" is a practical and pragmatic guide to modern, lightweight software architecture, specifically aimed at developers. You'll learn:The essence of software architecture.Why the software architecture role should include coding, coaching and collaboration.The things that you really need to think about before... - #2
CCIE Service Provider Ultimate Study Bundle
2 Books
Piotr Jablonski, Lukasz Bromirski, and Nick Russo have joined forces to deliver the only CCIE Service Provider training resource you'll ever need. This bundle contains a detailed and challenging collection of workbook labs, plus an extensively detailed technical reference guide. All of us have earned the CCIE Service Provider certification... - #3
1500 QUIZ COMMENTATI (3 libri)
3 Books
Tre libri dei QUIZ MMG Commentati al prezzo di DUE! I QUIZ dei concorsi ufficiali di Medicina Generale relativi agli anni: 2000-2001-2003-2012-2013-2014-2015-2016-2017-2018-2019-2020-2021 +100 inediti Raccolti in unico bundle per aiutarvi nello studio e nella preparazione al concorso. All'interno di ogni libro i quiz sono stati suddivisi per... - #4
Pattern-Oriented Memory Forensics and Malware Detection
2 Books
This training bundle for security engineers and researchers, malware and memory forensics analysts includes two accelerated training courses for Windows memory dump analysis using WinDbg. It is also useful for technical support and escalation engineers who analyze memory dumps from complex software environments and need to check for possible... - #5
Practical FP in Scala + Functional event-driven architecture
2 Books
Practical FP in Scala (A hands-on approach) & Functional event-driven architecture, aka FEDA, (Powered by Scala 3), together as a bundle! The content of PFP in Scala is a requirement to understand FEDA so why not take advantage of this bundle!? - #6
Modern C++ Collection
3 Books
Get All about Modern C++C++ Standard Library, including C++20Concurrency with Modern C++, including C++20C++20Each book has about 200 complete code examples. Updates are included. When I update one of the books, you immediately get the updated bundle. You can expect significant updates to each new C++ standard (C++23, C++26, .. ) and also... - #7
Linux Administration Complet
4 Books
Ce lot comprend les quatre volumes du Guide Linux Administration :Linux Administration, Volume 1, Administration fondamentale : Guide pratique de préparation aux examens de certification LPIC 1, Linux Essentials, RHCSA et LFCS. Administration fondamentale. Introduction à Linux. Le Shell. Traitement du texte. Arborescence de fichiers. Sécurité... - #9
Development and Deployment of Multiplayer Online Games, Part ARCH. Architecture (Vol. I-III)
3 Books
What's the Big Idea? The idea behind this book is to summarize the body of knowledge that already exists on multiplayer games but is not available in one single place.And quite a fewof the issues discussed within this series (planned as three nine volumes ~300 pages each), while known in the industry, have not been published at all (except for... - #10
Growing Agile: The Complete Coach's Guide
7 Books
Growing Agile: Coach's Guide Series This bundle provides a collection of training and workshop plans for a variety of agile topics. The series is aimed at agile coaches, trainers and ScrumMasters who often find themselves needing to help teams understand agile concepts. Each book in the series provides the plans, slides, handouts and activity...