Java Security settings block Applets by default now. Here's how you can allow Applets from a specific website to run in your browser.

OS X instructions
We will use http://www.turbulence.org as an example and show how to add Turbulence to your list of allowed Java sites

1. System Preferences -> Java Click Java icon at bottom.
   
   
   
2. Click Security Tab
   
   
   
3. Click Edit Site List next to the "Exception Site List" at bottom.
   A window opens entitled Exception Site List
   
   
   
4. Exception Site List, click Add and enter http://www.turbulence.org
   
   Click OK
   You will get a Security warning about HTTP. Click Continue
   
   
5. Your Java Control Panel now shows turbulence at the bottom. Click OK
   
   
   
6. Restart your browser and visit the site.

Prepared by Nick Didkovsky April 15, 2015