Head First Kotlin

Sat, 26 Sep 2026 21:05:00 -0400

Better than initially assessed: Chapter 2 introduces collections, good variance coverage (with a Pet hierarchy), covers extensions and their role in the stdlib, two lambda/HOF chapters. Unusual ordering: generics before lambdas. map/filter/fold deferred to lambda chapters. Coroutines appendix exists but dated.

Head First Kotlin uses the usual Head First spiral approach - introduce a concept lightly, let it sit, circle back with depth later - which meant it deferred anything not strictly load-bearing to the appendices. Labeled breaks and enum classes, both things I’d consider core language features, got pushed all the way to Appendix C rather than covered in the main chapters. That appendix is even honest about it in the title: “The Top Ten Things (We Didn’t Cover)” - ten separate topics, including packages, visibility modifiers, sealed classes, and object declarations, that never made it into the twelve main chapters at all.

Kotlin from Scratch

Sat, 26 Sep 2026 21:00:00 -0400

Brief summary: math/computational projects (Euclid, Sieve, Fibonacci, physics sims, fractals, sorting, A*), no extension functions, limited language features in intro chapters, good for drilling val instincts. Not idiomatic Kotlin.

Good typing practice and some genuinely interesting math/algorithms, but disappointing as a source of good Kotlin code. Chapters 1-2 covered language fundamentals in almost as much depth as all of Head First Kotlin, but that depth never returned. Nothing past chapter 2 touches generics, sealed classes, delegation, or coroutines. Chapter 3 was a whole detour into JavaFX I didn’t ask for and won’t need for Android/Swift, though I don’t regret typing it (the Stage/Scene boilerplate turned into a genuinely cool spiral, and the Gradle multi-module setup fights taught me more about the build system than the book itself did).

kotlin on Senior Software Engineer Learns Functional Programming

Head First Kotlin

Kotlin from Scratch