FlatLaf Demo & Theme Editor – CheerpJ + Java 17

FlatLaf Browser Demo

Java 25 via CheerpJ

Switch between the FlatLaf Demo and Theme Editor, both running unchanged JARs inside the browser via CheerpJ (Java 25).

How to use

1 Start with the Demo to explore FlatLaf look & feel options and components.
2 Switch to the Theme Editor to create or tweak themes. Save them inside the CheerpJ virtual filesystem.
3 Go back to the Demo and load your custom theme using the FlatLaf theme selection options.
Tip: A custom theme called CheerpJ Demo Theme is preloaded and can be selected from the theme list in the Demo.

This page runs the original FlatLaf JARs:
flatlaf-demo-3.7.jar and flatlaf-theme-editor-3.7.jar via cheerpjRunJar on a Java 25 runtime.

Runtime ready