BlueJ: a very quick introduction Adapted from notes by D. Matuszek, Upenn

BlueJ BlueJ is an IDE IDE = (Interactive|Integrated) Development Environment It includes an editor, which you use to write your programs a debugger, to help you find your mistakes a viewer, to see the parts of your program an easy way to run Java programs and program components an easy way to view documentation http://bluej.org/

(Iteractive|Integrated) Development Environments Most IDEs are language specific, tho some basic ones can be used with multiple languages. There are IDEs for most popular languages (Java, C++, C, Lisp, Smalltalk, Prolog, …) There are dozens of IDEs for Java Java’s capabilities for reflection makes it easy to write Reflection allows a program to examine or "introspect”, seeing it’s own components and (even) code. IDEs tend to be large, complicated and difficult to learn

BlueJ at UMBC Your best bet is to download and install BlueJ on your own computer. There are specific versions for Windows and MAC OS X There is a generic Java version that can be run on most any machine with Java (e.g., Linux, Solaris, …) BlueJ is installed on O:\BlueJ\ on the UMBC OIT PC servers You may need to show it where the java programs are

Open BlueJ, choose New Project

Name the project, click Create

Create and name a new Class or Applet The name of the class should begin with a capital letter

Double-click the new class to edit it The stripes show that the class "Drawing" is not compiled (ready to run)

Edit your class, then Compile it BlueJ starts you with a simple class or a simple applet. You can modify what BlueJ gives you, or just replace it with your own program.

If it's an applet: Right-click the class and choose Run Applet

If applet: choose how to run it, and what size it should be

Here's the running applet!

If application: right-click and choose void main(args)

Application: Just click Ok

Application results

Viewing classes BlueJ’s main display shows all of the classes in your package and the relationships between them

Viewing classes and instances You can interactively create Instances and call methods Attached to any class

Final notes You don't have to Save your work—BlueJ does that automatically for you when you compile If you quit BlueJ and come back later, use Open Project to continue where you left off This quick introduction does not replace working through the tutorial!

The End