The Java programming environment used in CS100 is DrJava, a free Integrated Development Environment (IDE). DrJava was developed by Professor Corky Cartwright at Rice University. Both DrJava and a professional IDE called Codewarrior are installed on computers in CIT labs in the Engineering Quad.
If you have problems, and if you have a laptop, the best thing to do is to bring it in to someone to look at.
You will need the Java software development kit (JDK) from the Sun website. If you have a Macintosh with Mac OS X, you almost certainly have the JDK installed already, so you don't have to download it. If you are using a PC running a version of Windows, chances are that you don't have the JDK yet, and you can download it here.
Several download options will be offered. Choose JDK 5.0, the J2SE Development Kit (JDK). Be sure you're getting the JDK and not just the JRE. Do not get the "bundles" that include other programming environments, such as netBeans. Once you start the download process, you will need to accept license agreements. When prompted for installation options, accept the default options, and run the .exe file. (Only customize the installation if you know your hardware well.)
The easiest thing for you to do is to download this version of DrJava: drjava-stable-20061025-1556.jar. This version should work whether you have Java 1.4.2 or Java 1.5, and we advise using it.
Alternatively, download the latest version of DrJava from this web page (by clicking the link). Choose a version of DrJava to download. The page will show you several versions of DrJava. Use the Current Stable Release (runs with JDK1.5.0, see above). On a Windows PC, click either on the jar file or on Stable Windows App. You'll be sent to select a location (mirror) from which to download DrJava. You may choose any of the mirrors.
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).
If the system tells you that it cannot find a file called tools.jar, you need to select the correct location of that file. On a PC, it is in some place like
You can also use a desktop tool to search for this file on your computer.
If you didn't set the correct path for the file tools.jar at installation time, set it after installation by going through DrJava's Preferences option. To do so, follow these menu items: Edit / Preferences / Resource Locations / Tools.jar Location. Then type or browse to the correct location.
There are several ways to run DrJava:
The demos given in class and in the demo sessions should help, if you take notes.
Second, information on using DrJava is in Appendix I of the course text and in Chapter 19 Chapter 19 of the accompanying CD ProgramLive. Watch the ProgramLive lectures! They are short and informative.
Third, here is documention on using DrJava on the web.
Do you get a message that looks like this?
It may mean that your computer has two different systems on it and is an inconsistent state. If your computer has jre5.0, then it cannot use SDK 4.7. Uninstall SDK4.7 and download JDK 5.0 and use its tools.jar.
One student reported not being able to create and use a JUnit tester; he got the error message: package junit.framework does not exist. To correct this, he did the following.
1. Downloaded file junit-4.1.jar (you can do it by clicking the link).
2. Copied it into C:\Program Files\Java\jdk1.5.0_10\lib. (If you are using a different jdk, then store it in the appropriate place.)
3. Opened DrJava, and hit Edit > Preferences > Resource Locations. In the popup window, in the field Extra Classpath, hit Add then clicked on the junit-4.1.jar file in the lib folder. Then hit Apply > OK.
There may be slight differences depending on your operating system, but this is the general idea.