If you want to push your Java skills to the next level, this book provides expert advice from Java leaders and practitioners. You’ll be encouraged to look at problems in new ways, take broader responsibility for your work, stretch yourself by learning new techniques, and become as good at the entire craft of development as you possibly can.

Edited by Kevlin Henney and Trisha Gee, 97 Things Every Java Programmer Should Know reflects lifetimes of experience writing Java software and living with the process of software development. Great programmers share their collected wisdom to help you rethink Java practices, whether working with legacy code or incorporating changes since Java 8.

A few of the 97 things you should know:

• "Behavior Is Easy, State Is Hard"―Edson Yanaga
• “Learn Java Idioms and Cache in Your Brain”―Jeanne Boyarsky
• “Java Programming from a JVM Performance Perspective”―Monica Beckwith
• "Garbage Collection Is Your Friend"―Holly K Cummins
• “Java's Unspeakable Types”―Ben Evans
• "The Rebirth of Java"―Sander Mak
• “Do You Know What Time It Is?”―Christin Gorman

Table of Contents

Chapter 1. All You Need Is Java

Chapter 2. Approval Testing

Chapter 3. Augment Javadoc with Ascii Doc

Chapter 4. Be Aware of Your Container Surroundings

Chapter 5. Behavior Is "Easy"; State Is Hard

Chapter 6. Benchmarking Is Hard-JMH Helps

Chapter 7. The Benefits of Codifying and Asserting Architectural Quality

Chapter 8. Break Problems and Tasks into Small Chunks

Chapter 9. Build Diverse Teams

Chapter 10. Builds Don't Have To Be Slow and Unreliable

Chapter 11. "But It Works on My Machine!"

Chapter 12. The Case Against Fat JARS

Chapter 13. The Code Restorer

Chapter 14. Concurrency on the JVM

Chapter 15. CountDownLatch-Friend or Foe?

Chapter 16. Declarative Expression Is the Path to Parallelism

Chapter 17. Deliver Better Software, Faster

Chapter 18. Do You Know What Time It Is?

Chapter 19. Don't hIDE Your Tools

Chapter 20. Don't Vary Your Variables

Chapter 21. Embrace SQL Thinking

Chapter 22. Events Between Java Components

Chapter 23. Feedback Loops

Chapter 24. Firing on All Engines

Chapter 25. Follow the Boring Standards

Chapter 26. Frequent Releases Reduce Risk

Chapter 27. From Puzzles to Products

Chapter 28. "Full-Stack Developer" Is a Mindset

Chapter 29. Garbage Collection Is Your Friend

Chapter 30. Get Better at Naming Things

Chapter 31. Hey Fred, Can You Pass Me the HashMap?

Chapter 32. How to Avoid Null

Chapter 33. How to Crash Your JVM

Chapter 34. Improving Repeatability and Auditability with Continuous Delivery

Chapter 35. In the Language Wars, Java Holds Its Own

Chapter 36. Inline Thinking

Chapter 37. Interop with Kotlin

Chapter 38. It's Done, But...

Chapter 39. Java Certifications: Touchstone in Technology

Chapter 40. Java Is a '90s Kid

Chapter 41. Java Programming from a JVM Performance Perspective

Chapter 42. Java Should Feel Fun

Chapter 43. Java's Unspeakable Types

Chapter 44. The JVM Is a Multiparadigm Platform: Use This to Improve Your Programming

Chapter 45. Keep Your Finger on the Pulse

Chapter 46. Kinds of Comments

Chapter 47. Know Thy flatMap

Chapter 48. Know Your Collections

Chapter 49. Kotlin Is a Thing

Chapter 50. Learn Java Idioms and Cache in Your Brain

Chapter 51. Learn to Kata and Kata to Learn

Chapter 52. Learn to Love Your Legacy Code

Chapter 53. Learn to Use New Java Features

Chapter 54. Learn Your IDE to Reduce Cognitive Load

Chapter 55. Let's Make a Contract: The Art of Designing a Java API

Chapter 56. Make Code Simple and Readable

Chapter 57. Make Your Java Groovier

Chapter 58. Minimal Constructors

Chapter 59. Name the Date

Chapter 60. The Necessity of Industrial-Strength Technologies

Chapter 61. Only Build the Parts That Change and Reuse the Rest

Chapter 62. Open Source Projects Aren't Magic

Chapter 63. Optional Is a Lawbreaking Monad but a Good Type

Chapter 64. Package-by-Feature with the Default Access Modifier

Chapter 65. Production Is the Happiest Place on Earth

Chapter 66. Program with GUTS

Chapter 67. Read OpenJDK Daily

Chapter 68. Really Looking Under the Hood

Chapter 69. The Rebirth of Java

Chapter 70. Rediscover the JVM Through Clojure

Chapter 71. Refactor Boolean Values to Enumerations

Chapter 72. Refactoring Toward Speed-Reading

Chapter 73. Simple Value Objects

Chapter 74. Take Care of Your Module Declarations

Chapter 75. Take Good Care of Your Dependencies

Chapter 76. Take "Separation of Concerns" Seriously

Chapter 77. Technical Interviewing Is a Skill Worth Developing

Chapter 78. Test-Driven Development

Chapter 79. There Are Great Tools in Your bin/ Directory

Chapter 80. Think Outside the Java Sandbox

Chapter 81. Thinking in Coroutines

Chapter 82. Threads Are Infrastructure; Treat Them as Such

Chapter 83. The Three Traits of Really, Really Good Developers

Chapter 84. Trade-Offs in a Microservices Architecture

Chapter 85. Uncheck Your Exceptions

Chapter 86. Unlocking the Hidden Potential of Integration Testing Using Containers

Chapter 87. The Unreasonable Effectiveness of Fuzz Testing

Chapter 88. Use Coverage to Improve Your Unit Tests

Chapter 89. Use Custom Identity Annotations Liberally

Chapter 90. Use Testing to Develop Better Software Faster

Chapter 91. Using Object-Oriented Principles in Test Code

Chapter 92. Using the Power of Community to Enhance Your Career

Chapter 93. What Is the JCP Program and How to Participate

Chapter 94. Why I Don't Hold Any Value in Certifications

Chapter 95. Write One-Sentence Documentation Comments

Chapter 96. Write "Readable Code"

Chapter 97. The Young, the Old, and the Garbage

About the Author

Kevlin Henney is an independent consultant and trainer. His work focuses on patterns and architecture, programming techniques and languages, and development process and practice. He has been a columnist for various magazines and online publications, including The Register, Better Software, Java Report, CUJ, and C++ Report. Kevlin is co-author of two volumes in the Pattern-Oriented Software Architecture series: A Pattern Language for Distributed Computing and On Patterns and Pattern Languages. He also contributed to 97 Things Every Software Architect Should Know