To write your applications, you need Eclipse, java runtime environment, and the java virtual machine. I hope you have a book on java. Eclipse editor can be found through Google. The virtual machine is hard to find, but should be on the same site as the runtime environment, or JDK.
Be Careful, or you won't be happy: All this Eclipse, java runtime, and virtual machine need to be on the same command path, Once everything is installed, you must be able to find the virtualMachine, in explorer, when you first open explorer look, under the tools area, make sure the virtual machine, will open. Now open Eclipse, this is the only way to build applications.
When you see Eclipse is open, read the help area this will tell you how to write java.
You need your applet tags to see the application in html, and xml. These tags are used twice with applets, once in the application. and another time in html, xml.
If you built an html database. you can see these application, as long as they are in the same files as the JDK. It's easiest to keep everything in one fault.