https://www.google.com.ua/search?q=java+app+for+ap...
stackoverflow.com/questions/3997867/does-mac-app-s...
The Good News
Yes, you can submit a Java app to the Mac App Store. Not true in the past, but it is true at least as of now in 2013.
One example is the successful MoneyDance personal finance app currently available for sale in the Mac App Store.
The Bad News
Preparing and submitting your app is neither simple nor easy. You have to jump through some hoops.