book

Java Cookbook, 5th Edition

by Ian F. Darwin

February 2025

Intermediate to advanced

684 pages

16h 14m

English

O'Reilly Media, Inc.

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Who This Book Is ForWhat’s in This Book?What’s Not in This BookOrganization of This BookJava BooksConventions Used in This BookUsing Code ExamplesO’Reilly Online LearningComments and QuestionsAcknowledgments
1.0. Introduction1.1. Hello, World: Compiling and Running Java with the Standard JDK1.2. Hello, World of Classless Main 21P1.3. Downloading and Using the Code Examples1.4. Compiling, Running, and Testing with an IDE1.5. Exploring Java with JShell 111.6. Using CLASSPATH Effectively1.7. Documenting Classes with Javadoc1.8. Beyond Javadoc: Annotations/Metadata1.9. Packaging and Running JAR Files1.10. Creating a JAR That Supports Multiple Versions of Java1.11. Packaging Web Tier Components into a WAR File1.12. Compiling and Running Java: GraalVM for Better Performance1.13. Getting Information About the Environment, OS, and Runtime
2.0. Introduction2.1. Designing Applications: Packages, Modules2.2. Using the Java Modules System2.3. Using JPMS to Create a Module2.4. Automating Compilation, Testing, and Deployment with Apache Maven2.5. Automating Compilation, Testing, and Deployment with Gradle2.6. Automating Dependency Management with Maven and Gradle2.7. Dealing with Deprecation Warnings2.8. Batch Refactoring for Warnings and Migrations2.9. Maintaining Code Correctness with Unit Testing: JUnit2.10. Isolating the Test Target with Mock Objects and Mockito2.11. Logging: Network or Local2.12. Setting Up SLF4J2.13. Network Logging with Log4j2.14. Network Logging with java.util.logging2.15. Maintaining Your Code with Continuous Integration2.16. Performance Timing2.17. Creating a Custom JDK Distribution with jlink2.18. Creating Platform-Specific Installers with jpackage
3.0. Introduction3.1. Taking Strings Apart with Substrings, Tokenizing, and Trimming Methods3.2. String Formatting with Formatter and printf()3.3. Building Strings with StringBuilder3.4. Processing a String One Character at a Time3.5. Aligning, Indenting, and Unindenting Strings3.6. Converting Between Unicode Characters and Strings3.7. Reversing a String by Word or by Character3.8. Expanding and Compressing Tabs3.9. Controlling Case3.10. Adding Nonprintable Characters into a String3.11. Creating a Message to the World with I18N Resources3.12. Using a Particular Locale3.13. Creating a Resource Bundle3.14. Program: A Simple Text Formatter
4.0. Introduction4.1. Regular Expression Syntax4.2. Checking If a String Matches a Regex4.3. Grouping: Specifying Parts of the Regex4.4. Finding the Matching Text4.5. Replacing the Matched Text4.6. Printing All Occurrences of a Pattern4.7. Controlling Case in Regular Expressions4.8. Matching Accented, or Composite, Characters4.9. Matching Newlines in Text4.10. Program: Full Grep
5.0. Introduction5.1. Checking Whether a String Is a Valid Number5.2. Converting Numbers to Objects and Vice Versa5.3. Taking a Fraction of an Integer Without Using Floating Point5.4. Working with Floating-Point Numbers5.5. Formatting Numbers5.6. Converting Among Binary, Octal, Decimal, and Hexadecimal5.7. Operating on a Range of Integers5.8. Formatting with Correct Plurals5.9. Generating Random Numbers5.10. Multiplying Matrices5.11. Optimizing Large Arithmetic Operations with Vector Operations 22C5.12. Using Complex Numbers5.13. Handling Very Large Numbers5.14. Program: TempConverter
6.0. Introduction6.1. Finding Today’s Date6.2. Formatting Dates and Times6.3. Converting Among Dates/Times and Epoch Seconds6.4. Parsing Strings into Dates6.5. Difference Between Two Dates6.6. Adding to or Subtracting from a Date6.7. Calculating Recurring Events6.8. Computing Dates Involving Time Zones6.9. Interfacing with Legacy Date and Calendar Classes
7.0. Introduction7.1. Using Arrays for Data Structuring7.2. Resizing an Array7.3. Simplifying Array Handling with the Arrays Class7.4. The Collections Framework7.5. Lists: Like an Array, but More Dynamic7.6. Using Generic Types in Your Own Class: Stack Demo7.7. How Shall I Iterate Thee? Let Me Enumerate the Ways7.8. Avoiding Duplicate Values with a Set7.9. Mapping with Hashtable and HashMap7.10. Storing Strings in Properties and Preferences7.11. Sorting a Collection7.12. Finding an Object in a Collection7.13. Converting Between Collections and Arrays7.14. Making Your Own Data Structures Iterable7.15. Multidimensional Structures
8.0. Introduction8.1. Object Methods: Formatting Objects with toString(), Comparing with Equals8.2. Constructor Simplification: Statements Before super(…) 22P8.3. Using Inner Classes8.4. Simplifying Data Objects with Records (or Lombok)8.5. Providing Callbacks via Interfaces8.6. Polymorphism/Abstract Methods8.7. Improving Interfaces with Default, Static, and Private Methods8.8. Using Typesafe Enumerations8.9. Using Type Pattern Matching8.10. Avoiding NPEs with “Optional”8.11. Controlling Subclassing with Sealed Types 178.12. Enforcing the Singleton Pattern8.13. Roll Your Own Exceptions8.14. Using Dependency Injection8.15. Combining Java Features for Data-Oriented Programming
9.0. Introduction9.1. Using Lambdas/Closures Instead of Inner Classes9.2. Using Predefined Lambda Interfaces or Rolling Your Own9.3. Simplifying Processing with Streams9.4. Simplifying Streams with Collectors9.5. Simplifying Streams with Stream Gatherers 22P9.6. Simplifying Streams with Your Own Stream Gatherer 22P9.7. Improving Throughput with Parallel Streams and Collections9.8. Using Existing Code as Functional with Method References9.9. Java Mixins: Mixing in Methods9.10. Functional Programming with Flow and Reactive Streams

10.0. Introduction10.1. Discovering Filesystem Paths10.2. Getting and Setting File and Directory Information: Files and Path10.3. Creating and Deleting Files or Directories10.4. Changing a File’s Name or Other Attributes10.5. About InputStreams/OutputStreams and Readers/Writers10.6. Reading and Writing Files10.7. Scanning Input with StreamTokenizer, Scanner, Parsers10.8. Reading from the Standard Input or from the Console/Controlling Terminal10.9. Copying a File10.10. Reassigning the Standard Streams10.11. Duplicating a Stream as It Is Written10.12. Reading/Writing a Different Character Set10.13. Those Pesky End-of-Line Characters10.14. Beware Platform-Dependent File Code10.15. Reading and Writing JAR or ZIP Archives10.16. Reading Files in a Filesystem-Neutral Way with getResource() and getResourceAsStream()10.17. Creating a Transient/Temporary File10.18. Getting the Directory Roots10.19. Using the File Watcher Service to Get Notified About File Changes10.20. Walking a File Tree (like Find)
11.0. Introduction11.1. Running Code in a Different Thread11.2. Using Virtual Threads for Better Performance11.3. Rendezvous and Timeouts11.4. Synchronizing Threads with the synchronized Keyword11.5. Simplifying Synchronization with Locks11.6. Locking with One Writer, Many Readers11.7. Sharing Data Among Threads—ThreadLocal and ScopedValue: Structuring Concurrency11.8. Simplifying Producer/Consumer with the Queue Interface11.9. Optimizing Parallel Processing with Fork/Join11.10. Scheduling Tasks: Future Times, Background Saving in an Editor
12.0. Introduction12.1. Using Data in Apache Spark12.2. Using R Interactively12.3. Comparing/Choosing an R Implementation12.4. Using R from Within a Java App: Renjin12.5. Using Java from Within an R Session12.6. Using R in a Web App
13.0. Introduction13.1. Some Major AI Software13.2. Using ChatGPT Directly13.3. Using ChatGPT via LangChain4j13.4. Making an AI Service with LangChain4j13.5. Conversing with Shadows13.6. Generating Images with LangChain4j13.7. Mixed Media Prompts: Inferences from Images with LangChain4j13.8. Running AI Locally with ollama
14.0. Introduction14.1. HTTP/REST Web Client—Modern API 1114.2. Contacting a Socket Server14.3. Finding and Reporting Network Addresses14.4. Handling Network Errors14.5. Reading and Writing Textual Data14.6. Reading and Writing Binary or Serialized Data14.7. Postcards of the Internet: Using UDP Datagrams14.8. URI, URL, or URN?14.9. Program: Sockets-Based Chat Client
15.0. Introduction15.1. Opening a Server Socket for Business15.2. Finding Network Interfaces15.3. Returning a Response (String or Binary)15.4. Handling Multiple Clients15.5. Serving the HTTP Protocol15.6. Securing a Web Server with TLS (formerly SSL) and JSSE15.7. Creating a REST Service/Microservice with JAX-RS15.8. Unix Domain Sockets—Even on Windows! 16
16.0. Introduction16.1. Generating JSON Directly16.2. Parsing and Writing JSON with Jackson16.3. Parsing and Writing JSON with org.json16.4. Parsing and Writing JSON with JSON-B16.5. Finding JSON Elements with JSON Pointer
17.0. Introduction17.1. Loading and Instantiating a Class Dynamically17.2. Printing Class Information17.3. Getting a Class Descriptor17.4. Finding and Using Methods and Fields17.5. Invoking Class Members via MethodHandles17.6. Listing Classes in a Package17.7. Accessing Nested Members of Same Class17.8. Accessing Private Methods and Fields via Reflection17.9. Constructing a Class from Scratch with a ClassLoader17.10. Constructing a Class from Scratch with JavaCompiler17.11. Constructing or Modifying Class Files with the Class-File API 22P17.12. Using and Defining Annotations17.13. Finding Plug-In-Like Classes via Annotations17.14. A Timing Program17.15. Program: CrossRef
18.0. Introduction18.1. Running an External Program from Java18.2. Running a Program and Capturing Its Output18.3. Calling Other Languages via javax.script18.4. Mixing Languages with GraalVM 2118.5. Calling Between Java and Native Code with the Foreign Function and Memory API 2218.6. Calling Other Languages via Native Code (JNI)18.7. Calling Java from Native Code with JNI
Introduction: Always in Motion the Java IsWhat Was New in Java 16 16What Was New in Java 17 LTS 17What Was New in Java 18 18What Was New in Java 19 19What Was New in Java 20 20What Was New in Java 21 LTS 21What Was New in Java 22 22What’s New in Java 23 23What’s New in Java 24 24Looking Ahead

Overview

As Java continues to evolve, this cookbook continues to grow in tandem with hundreds of hands-on recipes across a broad range of Java topics. Author Ian Darwin gets developers up to speed right away with useful techniques for everything from string handling and functional programming to network communication and AI.

If you're familiar with any release of Java, this book will bolster your knowledge of the language and its many recent changes, including how to apply them in your day-to-day development. Each recipe includes self-contained code solutions that you can freely use, along with a discussion of how and why they work.

Downloadable from GitHub, all code examples compile successfully. This updated edition covers changes up to Java 23 and most of Java 24. You will:

Learn how to apply many new and old Java APIs
Use the new language features in recent Java versions
Understand the code you're maintaining
Develop code using standard APIs and good practices
Explore the brave new world of current Java development

Ian Darwin has a lifetime of experience in the software industry, having worked with Java across many platforms and types of software, from Java's initial pre-release to the present, from desktop to enterprise to mobile.