Java SDK in Textpad wont show.?

I have installed JDK onto my Windows 7 computer and I have then installed Textpad to my computer and now that I am trying to get the SDK tools onto my computer i go to "Configure > Preferences" then I go to the tools bar and then I click add but the SDK is not showing up under the window? How can i get this to work. I am trying to get the Java compiler and the Java run applet.