Learn CODENAME-ONE with Real Code Examples

Codename One enables writing apps in Java or Kotlin that compile to native binaries across multiple platforms.

It provides a lightweight abstraction layer for native UI, device APIs, and system integration.

Ideal for Java developers who want to target mobile, desktop, and web from a single codebase.

Lightweight UI framework with cross-platform widgets

Native device API access (camera, GPS, storage, sensors)

Codename One build server for generating native binaries

MVC-based app structure

Push notifications and offline storage support

UI is built using Codename One components and layouts

Event handling is managed with listeners and callbacks

App lifecycle is controlled via Codename One lifecycle methods

Native device APIs are accessed through Codename One wrappers

App can be packaged and built for multiple platforms from a single project

src/ - Java/Kotlin source code

lib/ - external libraries and extensions

theme/ - UI themes and styles

build/ - output from build server

codenameone_settings.properties - project configuration

Design UI using Codename One visual designer or code

Implement app logic in Java/Kotlin

Test locally on simulator

Use build server to generate native binaries

Deploy to app stores or distribute internally

Beginner: simple mobile app with static UI

Intermediate: apps with device API integration

Advanced: apps with complex UI and offline storage

Expert: optimize performance and use native extensions

Community: contribute to Codename One libraries or plugins

Codename One vs Flutter: Flutter uses Dart and native rendering, Codename One uses Java/Kotlin

Codename One vs React Native: React Native uses JS, Codename One uses Java; build server generates native binaries

Codename One vs Native Android/iOS: Codename One is cross-platform, native apps need platform-specific code

Codename One is ideal for Java shops and rapid multi-platform deployment

Performance depends on UI complexity and use of native extensions

2012 – Initial release

2013–2015 – Core features and IDE integration developed

2016–2018 – Build server and extensions improved

2019–2022 – Expanded platform support and documentation

2023–2025 – Performance optimizations and new UI components

Codename One: cross-platform mobile framework using Java/Kotlin

Form: main UI container

Component: UI element like Button, Label, TextField

Build server: cloud service for generating platform binaries

Display: singleton for app instance and device access