Drjava  (Page 7/5)

DrJava is a lightweight pedagogical environment for Java development created by the Programming Languages Team (PLT) at Rice University. DrJava provides a way to edit and save java code with key words highlighting, curly brace matching, and an interactive environment to manipulate objects and test code without having to write the main method. It can be freely downloaded from the web. Please see the DrJava home page

Dr java tutorials

• Quick Start Guide : This guide covers the most important aspects of using DrJava, such as opening and saving files, compiling, testing, debugging and setting preferences.
• Full Documentation : This is the full documentation for DrJava, covering all aspects of the system.
• FAQ : This Frequently Asked Questions list covers many of the common issues that come up when running DrJava.
• Video Tutorials : Some short introductory Flash vidoes on installing Java and DrJava and running DrJava. This is a good place to start for beginnings to get a feel for what can be done with DrJava. Note: The videos may not run in Internet Explorer, if not, please try accessing the videos using another browser, such as Firefox.

Editing

Definitions Pane: When you run DrJava you will see a window appear. This window (GUI) consists of four subwindows. The top half of the GUI constitutes the Definitions pane. You type in all the class definitions here. After you type in some code, you need to click on the save button before you can compile your code. All the classes in the Definitions pane will be saved in a single file. There should only be one public class in the Definitions window, and the saved file should have the same name as that of the public class with the extension .java .

Compiling

Compiler Output Pane: You compile your Java code by clicking on the Compile All button in the menu bar at the top. Every time you compile your code, DrJava will display all compile error messages here. Clicking on an error message will highlight the line where the error is suspected to take place in the Definitions pane. If there is no compile error, DrJava will declare success in this pane.

Running

Interactions pane: There are several ways to run your Java code. For now, we will restrict ourselves to the Interaction pane at the bottom of the main GUI window. This is where you can type in any valid Java statement. Usually, you would type in code to instantiate objects of classes defined in the Definitions window, and call their methods to check whether or not they perform correctly. Typing a valid Java expression terminated with a semi-colon and then pressing the Return ( Enter ) key, will cause DrJava to evaluate the expression but NOT printing the result. If you want DrJava to print the value of the result in the Interactions window, you should press Return without terminating the expression with a semi-colon. There is a menu item to reset (i.e. clear) the Interactions window. Another way to clear the Interactions window is to force a re-compile by editing the Definitions pane. If your code has printing statements, the output will be displayed in the Console Output pane.