This gem contains everything required to write cross-platform desktop applications with JRuby and SWT.


  • Includes all the jar files needed.
  • Selects and loads the correct SWT jar for the platform.
  • Imports of many swt Java classes into a 1-1 mapped Ruby class hierarchy.
  • Examples to get you started. (For more see this SWT cookbook)

Why JRuby/SWT?

  • Fast, compatible Ruby implementation.
  • JRuby and SWT are flawlessly cross-platform.
  • SWT has native widgets (for the most part).
  • SWT powers Eclipse, so there's nothing you need that it doesn't do.
  • You don't need to touch Java! Write everything in Ruby.


require 'java'
require 'swt'

Running the Example

Linux / windows:

jruby examples/button.rb


jruby -J-XstartOnFirstThread examples/button.rb


4.6 Removed MacOS 32 bit support (SWT project doesn't seem to support it any more)