The Lab Computer

Unless you plan to type in a foreign language, you'll want to disable the Input Method software, which interferes with the keyboard focus. Close any windows you may have opened. Go to the menu in the upper left and choose System -> Preferences -> More Preferences -> Input Method -> Never Use Input Methods. Then log out and log back in again.

Your Own Computer

You may choose to do all your work on the lab machine. If so, you'll never need to install Java or DrJava, since this software has already been installed for you on the lab computers.

If you prefer to work on your own computer, here's what you'll need:

1. Java.

   If you've got a Mac, then you've already got Java, and you can move on to the next step! If you don't have a Mac, then you'll need to download and install the JDK.

   Java comes in two flavors: JRE and JDK. JRE stands for Java Runtime Environment. This is what you would need if the only thing you wanted to do was to run someone else's already-compiled Java programs. You probably already have this on your computer, but that doesn't matter to you now. What you need is the JDK, which stands for Java Development Kit. The JDK can do everything the JRE can (run compiled Java programs), and it can also compile the Java programs you write.

   Download the JDK by going here and clicking on the button that lets you download the "Java SE Development Kit (JDK) 6" (with whatever update number). The JDK is big, so make sure you've got a good Internet connection and a lot of time. Even after you've downloaded it, it may take 30 minutes just to install it. This is normal. Be glad you won't have to do this again (until you get a new computer).

2. DrJava.

   DrJava is not Java. Java is the thing that compiles your programs and runs them. The programs you write are nothing but text files full of Java code, and Java is the thing that (a) compiles those .java text files into .class files (equivalent programs written in a scary language called "Java Bytecode"), and then (b) runs your compiled code.

   All of this you can do without DrJava! But, DrJava makes this all a little easier for you, by showing you a pretty window with all your code in pretty colors and indented nicely. It also provides you with handy buttons that make it easy for you to compile your code, and with a handy interactions pane that makes it easy for you to run your code. (If Java is like the electronic circuitry inside your IPod, then DrJava is like the plastic case around it.)

   Like all software that runs on your computer, Java and DrJava are programs themselves. And DrJava is a program that was written in Java!

   Download DrJava here.