https://afanasev.net/categories/kotlin-library/Recent content in Kotlin-Library on afanasev.netHugoen-USTue, 13 Aug 2019 14:18:12 +0700https://afanasev.net/kotlin-library/2019/08/13/sekret.htmlTue, 13 Aug 2019 14:18:12 +0700https://afanasev.net/kotlin-library/2019/08/13/sekret.html<h2 id="problem">Problem</h2> <p>One of Kotlin&rsquo;s most appreciated features is the data class. With a single keyword, the compiler automatically generates <code>equals</code>, <code>hashCode</code>, <code>copy</code>, <code>componentN</code>, and <code>toString</code> — eliminating an entire category of boilerplate that Java developers had to write and maintain by hand. For domain objects, value types, and state containers, data classes are the obvious choice.</p> <p>The <code>toString</code> function, in particular, is invaluable for debugging. When you log a data class instance, you get a complete, readable snapshot of its state: every field name and value, formatted cleanly. This is exactly what you want during development.</p>https://afanasev.net/kotlin-library/2019/08/12/kson.htmlMon, 12 Aug 2019 14:18:12 +0700https://afanasev.net/kotlin-library/2019/08/12/kson.html<p>Kotlin data classes are an ideal fit for API response models. They are concise, immutable by default, and come with auto-generated <code>equals</code>, <code>hashCode</code>, <code>copy</code>, and <code>toString</code> — everything you need from a value object representing a network payload. Pairing them with GSON is natural and widely practiced across the Android ecosystem.</p> <p>However, there is a subtle but serious trap hiding in that combination — one that silently violates Kotlin&rsquo;s type safety guarantees and can cause crashes that are difficult to reproduce and frustrating to diagnose.</p>