An iOS or Android update can change a screen you shipped without you changing a line of code. If your app builds its UI from UIKit, SwiftUI, Compose, or Material widgets, Apple or Google owns those widget implementations. Codename One does something different. It statically links our lightweight component implementation into your native app. The UI you test is the UI your users keep after the next OS update. An update can still break a platform API or permission contract, but it cannot swap our button implementation for a new one.
What is Codename One? Codename One is an open-source framework for building native iOS, Android, desktop, and web apps from a single Java or Kotlin codebase. Learn more at codenameone.com.
Lightweight does not mean a Java paint loop limping behind the platform. On iOS, components paint through our Metal pipeline. The moving Liquid Glass tab lens in this post is a Metal shader on the frame's existing command buffer, with no transfer of pixels back to the CPU. At the same time, last week's ParparVM work brought our ahead-of-time VM to geomean parity with warmed Java 25 across ten benchmarks. Six finished at or ahead of HotSpot.
The tradeoff is that our UI does not inherit Apple's or Google's latest redesign for free. We have to study it, reproduce the parts that make sense, and test the result. That is work we take on so you can work on your app instead of working for the Apple and Google design teams. You decide when your app adopts a new look. The OS does not decide for you on upgrade day.
