Go for Java Programmers: Learn the Google Go Programming Language

 Table of Contents....5

About the Author....12

About the Technical Reviewer....13

Acknowledgments....14

Introduction....15

Assessments....30

Part I: First Look at Go....31

Chapter 1: A Brief Look at Go vs. Java....34

Go Is a Compiled (vs. Interpreted, As Java Is) Language....35

Go and Java Share Similar Program Structure....36

Go and Java Have Some Code Style Differences That Influence How Code Is Structured....36

Both Go and Java Are Procedural Languages....37

Java Is an Object-Oriented (OO) Language, While Go Is Not Fully OO....38

Java Is a Highly Functional Language, Go Is Less So....39

Java Is a Highly Declarative Language, Go Is Less So....39

Many Java Features Are Annotation Driven....39

Go Does Not Support Exceptions....40

Both Java and Go Use Managed Memory (Garbage Collectors)....40

Go and Java Both Support Concurrency but in Different Ways....41

Go’s Runtime Is Simpler Than the JRE....41

The Go Program Build Process Is Different....42

Go and Java Have Similar Release Cycles....42

Chapter 2: What Java Has That Go Does Not....44

Multiple Assignments....44

Statements and Operators....44

Assert Statement....45

While and Do Statements....45

Throw Statement/Throws Clause....46

Strictfp, transient, volatile, synchronized, abstract, static....46

Objects and Classes (OOP) and Inner Classes, Lambdas, this, super, Explicit Constructors....46

Generic Types and Methods....49

Extensive Functional Programming Capabilities....49

Boxing of Primitive Values....50

Source Annotations....50

Multiple Visibilities....51

Overloaded/Overridden Functions....51

Formal Enums....51

Built-in Binary Data Self-Serialization....52

Concurrent Collections....52

Chapter 3: A Deeper Comparison of Go and Java....53

Part II: The Go Language....58

Chapter 4: Key Go Aspects....59

Simple Go Program Example....61

Go Packages....67

Go Comments....70

Go Build/Run Process....71

Go Playground....72

Go Integrated Development Environments....76

Running Go Programs....81

Building Go Programs....82

Bytecode vs. Real Code....85

Go Command-Line Tools....87

Tools Bundled in the Go Command....88

Other Tools....90

Go Runs Programs Instead of Classes....90

Go Memory Management....92

Go Identifiers....97

Go Scopes....99

Go Scopes vs. Go Source Files....102

Initializing Go Variables....104

Lifetimes of Go Identifiers....106

Go Module Summary....107

Go Assignments and Expressions....113

Text Formatting in Go....115

Goroutines....120

Issues with Concurrency....120

Go Concurrency....123

Goroutines by Example....126

Chapter 5: Go Basic Features....136

Language Keywords....136

Operators and Punctuation....139

Go Operator Precedence....144

Go Built-in Functions....145

Chapter 6: Go Types....147

Primitive/Built-in Types....147

Numbers....147

Characters and Strings....149

Reference vs. Pointer Types....150

Drill Down on Basic Data Types....153

Boolean Type....153

Integer Types....153

Floating-Point Types....154

When nil Can Go Wrong....155

Programmer-Defined Types....156

Arrays....161

Slices....163

Maps....168

Functions....171

Methods As Functions....176

Any Declared Type Can Have Custom Functions....177

Functions As Values....179

Structs....183

Structure Fields....186

Structure Literals....188

Nested Structures....189

Structure Field Alignment....191

Interfaces....192

Application of Interfaces....195

Composite Interfaces....198

Channels....199

Variable Declarations....203

Constant Declarations....206

Type Casting....208

Type Testing....209

Derived Type Declarations....212

Chapter 7: Errors and Panics....216

Go Errors....216

Go Panics....218

Errors and Panics Illustrated....222

Chapter 8: Go Statements....229

Package and Import Statements....230

Assignment Statements....231

Declaring Variables....233

Declaring Named Constants....235

If/Else Statements....236

Switch Statement....239

While Statement....242

Do-While Statement....243

For with Index Statement....243

For over a Collection Statement....244

Forever Statement....246

Break and Continue Statements....247

Goto Statement....248

Return Statement....249

Defer Statement....250

Go Statement....251

Select Statement....252

Chapter 9: Applications for Interfaces....254

An Interface Is the Key....254

On Dependency Injection....257

On Aspect-Oriented Programming....265

Chapter 10: Go Unit Tests and Benchmarks....270

Test Cases and Benchmarks in Go....271

Test Cases in Java....283

Chapter 11: Going into the Future....288

Improved Error Handling....288

Go Generics....290

Capstone Game of Life Example....296

Game of Life Go Source....301

Capstone Project in Java....302

Main.java....303

Server.java....310

Game.java....322

Utility.java....335

Formatter.java....336

ParameterProvider.java....340

AnnimatedGifWriter.java....341

Logger.java....344

Capstone Project in Go....347

Main.go....347

Server.go....352

Game.go....361

Utility.go....373

Go Doc Output....374

API Outputs....376

Game Outputs....380

Part III: Go Library Survey....383

Chapter 12: Key Package Comparison....395

Java Lang Packages....395

Java IO Package....400

Java Text Package....403

Java Time Packages....405

Java Util Packages....406

Chapter 13: Key Method/Function Comparison....413

Chapter 14: Go Package Survey....419

File Access with Go....419

Compression Services....422

Archive Packages....422

Compression Packages....425

Image....426

Input/Output (I/O)....429

Bytes Package....435

Format Package....439

Data Collections....441

Sorting....444

Context Package....446

Cryptography and Hashing and Data Encoding....450

Encoding Packages....451

Unicode Encoding Packages....453

Chapter 15: SQL Database Access....456

Chapter 16: Client and Server Support....467

MIME Packages....467

Network Packages....467

The Net Package....468

The HTTP Template Package....480

The Net.HTTP Package....485

URL Package....495

Chapter 17: Go Runtime....497

Errors Package....497

Flag Package....498

Log Package....503

Math Package....510

Operating System Support Packages....525

Reflection Package....533

Regular Expression Package....535

Go Runtime Packages....537

String Processing Packages....538

Concurrency and Goroutines....543

Testing Package....546

Time and Date Package....551

Appendix A: Installing Go....558

Appendix B: Some Go FAQs....569

Appendix C: Go Gotchas to Look Out For....577

Appendix D: Mark-Sweep Pseudocode....582

Appendix E: ASCII vs. UTF-8....586

Index....589

Get an in-depth introduction to the Go programming language and its associated standard runtime libraries. This book is targeted towards programmers that already know the Java programming language and uses that Java knowledge to direct the learning of Go. You will get a deep understanding of the Go language and obtain a good introduction to the extensive Go standard libraries.

This book teaches Go through clear descriptions of Go features, contrasting them with similar Java features and via providing extensive code examples. After reading this book you will be knowledgeable enough about Go and its libraries to begin doing effective programming using the Go language.

Go for Java Programmers is structured more like a tutorial than a reference document. It covers key features of Go, but not every little detail as a reference might. Its goal is to get you competent enough in Go and its runtime that you can begin to effectively writeGo programs.

What You Will Learn

• Examine the key Go Runtime libraries and how they compare to Java libraries
• See when it is appropriate to use the Go language instead of the Java language
• Read and understand programs written in Go
• Write many programs in Go
• Determine when Go is an appropriate language to develop applications in
• Discover how the Go and Java languages and development experience compare and contrast

Who This Book Is For

Primarily existing professional Java programmers or students that already know something about Java. A basic understanding of Java is expected. Some basic programming experience with imperative languages is expected.