September 2019
Intermediate to advanced
462 pages
11h 3m
English
Content preview from Programming KotlinBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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Generics: Variance and Constraints of Parametric Types
The desire to reuse code shouldn’t come at a cost of compromising type safety. Generics bring a nice balance to this issue. With generics you can create code that can be reused for different types. At the same time, the compiler will verify that a generic class or a function isn’t used with unintended types. We’ve enjoyed a fairly good amount of type safety with generics in Java. So, you may wonder, what could Kotlin possibly provide to improve? It turns out, quite a bit.
By default, in Java, generics impose type invariance—that is, if a generic function expects a parametric type T, you’re not allowed to substitute a base type of T or a derived type of T; the type has to be exactly the expected ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.