Enable Java Applet in Safari browser 7 and 8 on Mac OS X (Mavericks and Yosemite)

1. Make sure you have the latest Java installed, click here. In the test page, clicked on the words "Inactive Plug-In" to start the applet.
2. Go to the web page contains Java applet.
3. When you see a dialog box asking "Do you want to trust the website "xxx.org"?", click Trust to allow the plug-in to run. This is only requested once, but it will be requested for each website.
4. If the applet is self-signed, you need to explicitly allow the website in "Java Control Panel":
   • Open System Preferences, then click Java, then click reopen Java Control Panel
     
     
     
     
   • In Java control panel, activate Security tab, tick Enable Java content in browser, set security level to high, the click Edit site list... to add exception site
     
     
   • Click Add button then enter the site address. Note: the protocol is required. And the port number need to specified if it is not the standard port for the protocol.
     
     
5. If the Java applet reads/writes local files, it will not work. Because Safari blocks file i/o by default. You need to do the following to allow it:
   • In Sarafi, open Safari menu, then select Preferences..., in the dialog, select Security, allow Internet plug-ins, then click Website settings...
   • In the left column of the new dialog window, select Java; In the right column site list, select the website, click the drop-down menu button, then select Run in unsafe mode.
     

see also

• Allowing Java Web Applications