If you want to download a java environment for your personal PC, you have a few options. JBuilder is an IDE that is available from Borland: http://www.borland.com/jbuilder/. I do not use an IDE, so I will only provide you with minimal assistance with respect to using JBuilder. Another option is to download the Sun Java SDK: http://java.sun.com/j2se/1.4.2/download.html. Sun's website is a little confusing, but you want to download J2SE 1.4.X. This will give you a java environment you can use to compile and run java programs from the command line. If you choose this option, you will also need to have a text editor. I like to use emacs (http://www.gnu.org/software/emacs/emacs.html) but you can use any editor you like. However, you need to make sure that you are saving your files in plain text. In other words, don't use MSWord.
By 9/15 all of you should have an account in Clapp 202. If you log into Windows, JBuilder should be available for your use. Similarly, you can use the JBuilder compiler to compile from the command line in windows. If you want help getting started with this, let me know. Alternatively, the command line java compiler should be available on the Linux partition. Again, if you want help getting started with this, let me know. (Especially during my office hours!) I would be happy to come to the lab to get you set up.