CS100M/CIS121/EAS121:
Java Resources

General Information

The primary Java programming environment used in CS100 is Dr. Java, which is a free Integrated Development Environment (IDE). DrJava was developed by Professor Corky Cartwright at Rice University. Both DrJava and a more professional IDE call Codewarrior are installed on CIT's computers.

Installation

The Java Virtual Machine

For DrJava, you need a Java Virtual Machine, v1.3 (or later) virtual machine and software development kit (SDK). If you are using a PC running a version of Windows, chances are that you don't have it yet (although a recent court ruling may change that in the future). If you have a Macintosh with Mac OS X, you almost certainly have the Java SDK installed already, and you don't have to download the SDK.

Downloading DrJava

Download DrJava by clicking this link. The page will show you several versions of DrJava. Get the latest. Warning: you may get a dialog saying something about a JAR archive security check. If you do, just right-click on the DrJava download link and select Save Link As (or the equivalent in your browser).

A common DrJava problem: finding tools.jar

Question: I downloaded Sun's J2SE SDK and DrJava. When it came to actually running DrJava, the following message kept popping up although DrJava still managed to run without me finding the file. What should I do?

Compiler not found. The file you chose did not appear to contain the compiler. Would you like to pick again? The compiler is generally located in 'tools.jar', in 'lib' subdirectory under your JDK installation director. (If you say 'No', DrJava will be unable to compile programs.)

Answer: First, make sure you installed the Java SDK, not the JRE. (See above.) Now you need to find a file called tools.jar. If you're using Windows, then when you installed the SDK, you probably put it in Program Files. The name of the Java folder is probably something like j2sdk1.4.2. Look inside that for a directory called lib, and inside lib, look for tools.jar.

Running DrJava

There are several ways to run DrJava:

• From the command line, you can type java -jar drjava-stable-version.jar.
• On many platforms, you can simply double-click the jar file to start DrJava.
• On OS X, you can download drjava-stable-version-osx from the download page. You can then run DrJava as a normal application.

For documentation, refer to DrJava on the web.