--- title: "R8 Optimization: Class Reflection and Forced Inlining" url: https://daily.dev/posts/r8-optimization-class-reflection-and-forced-inlining-xiy4fj9if source_url: https://jakewharton.com/r8-optimization-class-reflection-and-forced-inlining type: article source: "Jake Wharton" published: 2026-07-05T07:13:39.866Z updated: 2026-07-05T07:15:18.539Z tags: ["java", "android"] reading_time: 6 upvotes: 0 comments: 0 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # R8 Optimization: Class Reflection and Forced Inlining **[Jake Wharton](https://daily.dev/sources/jakewharton)** · 6 min read · 0 upvotes · 0 comments ## Summary R8, Android's optimizer, can replace runtime reflection calls like `getClass().getSimpleName()` with compile-time string constants through whole-program analysis. When R8 determines a class has no subtypes, it substitutes `getClass()` with a class literal, then chains that into existing class constant optimizations to produce a plain string. For cases where the class isn't directly known at the call site — such as a library method accepting an Activity — the undocumented `-alwaysinline` directive can force inlining of the method body into each call site, making the class known at compile time and enabling the full optimization chain. The post warns that `-alwaysinline` is unsupported and may change; Kotlin's `inline` modifier is the stable alternative for Kotlin callers. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: --- Tags: [#java](https://daily.dev/tags/java), [#android](https://daily.dev/tags/android) [View this post on daily.dev](https://daily.dev/posts/r8-optimization-class-reflection-and-forced-inlining-xiy4fj9if)