When Redcar first runs, it downloads the xulrunner dist file [1] to somewhere, and uses the rubyzip [2] gem to unzip it.
Then the JRuby to create a browser instance looks like this, which should be readily translateable to Java or whatever since the JRuby Swt API is auto-translated from the Java API. The xulrunner directory is the result of unzipping the .zip file.
if Redcar.platform == :windows
xulrunner_path = (Redcar.root + "/vendor/xulrunner").gsub("/", "\\")
java.lang.System.setProperty(