I wish “Eclipse Collections Categorically: Level up your programming game” existed when I first use Eclipse Collections. n the preface, Don compares Clipper, Smalltalk and Java (pre Java 8) to give a feel for the differences in syntax. Eclipse Collections was invented before Java supported lambdas so this is helpful in understanding the environment it was created in. There's also an appendix with more on Smalltalk which I found interesting. Speaking of history, Don goes briefly explains 20 years of this library evolving from Caramel to Gs Collections to Eclipse collections.
The bulk of the book is going through the features of the library with annotated examples. There are useful comparison throughout like to Streams. Things not available in the JDK like using of() with a SortedSet are highlighted. I especially liked the feature compare collect() in JDK streams vs Eclipse Collections.
Concepts are well explained like eager vs lazy. The code examples are fun and there are some running themes like United States Presidents are used in a bunch of examples.
Chapter 11 was great by pulling together concepts from earlier in the book. I hadn't picked up on the term “fused methods” earlier on.
Also, the book is in color which is great for some of the diagrams (like class/interface diagrams) and makes the code feel very much like an IDE. Speaking of code examples, most of them have a “cost” visual showing how easy or hard they are to read. And there's a table early on in the book showing how that cost is calculated if curious. You don't need to remember that though. The cost is comparative so ones with a lower cost are definitely easier to read.
Chapters end with a table summarizing the APIs covered. With over 200 code examples and over 50 reference tables, this book is great for learning the library, deepening your understanding of it or even appreciating it more. (This matches the target audience of Java devs who have or haven't used Eclipse collection along with library designers.) Thanks Don!