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Sep 19, 2024 · Note: BlueJ now uses Java 11+, which requires a 64-bit operating system, which 95+% of users will have. For 32-bit operating systems, download BlueJ 4.1.4 instead. Download previous versions or old source code archives. The source code for BlueJ is now available on Github.
- Extensions
This extension gives the BlueJ user a handy way to quickly...
- About Bluej
In the late nineties, Michael Kölling developed a...
- Technical Support
Submission. Important: Before you proceed, please check the...
- Teacher Support
The Blueroom is a forum for educators using BlueJ.. For more...
- Chapter Sequence
Chapter 2 opens up class definitions and investigates how...
- Raspberry PI
BlueJ is an Integrated Development Environment (IDE) written...
- Resources
Text input/output in Java, again straight from the source:...
- Blackbox
The exact rate at which data will be sent is dependent on...
- Extensions
Sep 16, 2024 · BlueJ is one of the most popular Java IDEs for students and beginners who wish to learn Java programming. The program comes with quick installation , and lets you set up the application within seconds.
Sep 19, 2024 · Projects can be pure-Java (as in BlueJ 3 and earlier), pure Stride or a mix of Java and Stride. Support is providing for converting between Java and Stride. BlueJ 4 adds support for the Git version control system (and retains support for Subversion).
- 1.1 About BlueJ
- 1.2 Scope and audience
- 1.3 Copyright, licensing and redistribution
- 1.4 Feedback
- 2.4 Installation problems
- 3.1 Starting BlueJ
- 3.2 Opening a project
- 3.3 Creating objects
- 3.4 Execution
- 3.6 Compilation
- 3.7 Help with compiler errors
- 4 Doing a bit more...
- 4.1 Inspection
- 4.2 Passing objects as parameters
- 5 Creating a new project
- 5.1 Creating the project directory
- 5.2 Creating classes
- 5.3 Creating dependencies
- 5.4 Removing elements
- 6 Using the code pad
- 6.4 Inspecting objects
- 6.8 Command history
- 7 Debugging
- 7.2 Stepping through the code
- 7.3 Inspecting variables
- 7.4 Halt and terminate
- 8 Creating stand-alone applications
- 9.1 Running an applet
- 9.2 Creating an applet
- 9.3 Testing the applet
- 10.1 Opening non-BlueJ packages in BlueJ
- 10.2 Adding existing classes to your project
- 10.3 Calling main and other static methods
- 10.4 Generating documentation
- 10.5 Working with libraries
- 10.6 Creating objects from library classes
- GeneratedCaptionsTabForHeroSec
This tutorial is an introduction to using the BlueJ programming environment. BlueJ is a JavaTM development environment specifically designed for teaching at an introductory level. It was designed and implemented by the BlueJ team at Deakin University, Melbourne, Australia, and the University of Kent at Canterbury, UK. More information about BlueJ i...
This tutorial is aimed at people wanting to familiarize themselves with the capabilities of the environment. It does not explain design decisions underlying the construction of the environment or the research issues behind it. This tutorial is not intended to teach Java. Beginners of Java programming are advised to also study an introductory Java t...
The BlueJ system and this tutorial are available 'as is', free of charge to anyone for use and non-commercial re-distribution. Disassembly of the system is prohibited. No part of the BlueJ system or its documentation may be sold for profit or included in a package that is sold for profit without written authorisation of the authors. The copyright ...
Comments, questions, corrections, criticisms and any other kind concerning the BlueJ system or this tutorial are very welcome encouraged. Please mail to Michael Kölling (mik@mip.sdu.dk). of and feedback actively
If you have any problems, check the Frequently Asked Questions (FAQ) on the BlueJ web site (http://www.bluej.org/help/faq.html) and read the How To Ask For Help section (http://www.bluej.org/help/ask-help.html).
On Windows and MacOS, a program named BlueJ is installed. Run it. On Unix systems the installer installs a script named bluej in the installation directory. From a GUI interface, just double-click the file. From a command line you can start BlueJ with or without a project as an argument: $ bluej or $ bluej examples/people Figure 1: The BlueJ main w...
Summary: To open a project, select Open from the Project menu. BlueJ projects, like standard Java packages, are directories containing the files included in the project. After starting BlueJ, use the Project – Open... menu command to select and open a project. Some example projects are included with the standard BlueJ distribution in the examples...
Summary: To create an object, select a constructor from the class popup menu. One of the fundamental characteristics of BlueJ is that you cannot only execute a complete application, but you can also directly interact with single objects of any class and execute their public methods. An execution in BlueJ is usually done by creating an object and th...
Summary: To execute a method, select it from the object popup menu. Now that you have created an object, you can execute its public operations. (Java calls the operations methods.) Click with the right mouse button on the object and a menu with object operations will pop up (Figure 5). The menu shows the methods available for this object and two sp...
Summary: To compile a class, click the Compile button in the editor. To compile a project, click the Compile button in the project window. After inserting the text (before you do anything else), check the project overview (the main window). You will notice that the class icon for the Staff class has changed: it is striped now. The striped appearanc...
Summary: To get help for a compiler error message, click the question mark next to the error message. Very frequently, beginning students have difficulty understanding the compiler error messages. We try to provide some help. Open the editor again, introduce an error in the source file, and compile. An error message should be displayed in the edito...
In this section, we will go through a few more things you can do in the environment. Things which are not essential, but very commonly used.
Summary: Object inspection allows some simple debugging by showing an object’s internal state. When you executed methods of an object, you might have noticed the Inspect operation which is available on objects in addition to user defined methods (Figure 5). This operation allows checking of the state of the instance variables (“fields”) of objects....
Summary: An object can be passed as a parameter to a method call by clicking on the object icon. Objects can be passed as parameters to methods of other objects. Let us try an example. Create an object of class Database. (You will notice that the Database class has only one constructor which takes no parameters, so construction of an object is stra...
This chapter takes you to a quick tour of setting up a new project.
Summary: To create a project, select New... from the Project menu. To create a new project, select Project – New... from the menu. A file selection dialogue opens that lets you specify a name and location for the new project. Try that now. You can choose any name for your project. After you click OK, a directory will be created with the name you sp...
Summary: To create a class, click the New Class button and specify the class name. You can now create your classes by clicking the New Class button on the project tool bar. You will be asked to supply a name for the class - this name has to be a valid Java identifier. You can also choose from four types of classes: abstract, interface, applet or “s...
Summary: To create an arrow, click the arrow button and drag the arrow in the diagram, or just write the source code in the editor. The class diagram shows dependencies between classes in the form of arrows. Inheritance relations (“extends” or “implements”) are shown as arrows with a hollow arrow head; “uses” relations are shown as dashed arrows wi...
Summary: To remove a class or an arrow, select the remove function from its popup menu. To remove a class from the diagram, select the class and then select Remove from the Edit menu. You can also select Remove from the class’s popup menu. Both options work for arrows as well: You can either first select the arrow and then select Remove from the me...
The BlueJ code pad allows quick and easy evaluation of arbitrary snippets of Java code (expressions and statements). Thus, the code pad can be used to investigate details of Java semantics and to illustrate and experiment with Java syntax.
Summary: To inspect result objects in the code pad, double-click the small object icon. If you want to inspect an object that was returned as a result from a code pad expression, you can do this without placing it onto the object bench: you can just double-click the object's icon to open the usual object inspector.
Summary: Use up-arrow and down-arrow keys to make use of the input history. The code pad keeps a history of your previously used inputs. Using the up or down arrow keys, you can easily recall previous input lines, which can be edited before being reused.
This section introduces the most important aspects of the debugging functionality in BlueJ. In talking to computing teachers, we have very often heard the comment that using a debugger in first year teaching would be nice, but there is just no time to introduce it. Students struggle with the editor, compiler and execution; there is no time left to ...
Summary: To single-step through your code, use the Step and Step Into buttons in the debugger. Now that we have stopped the execution (which convinces us that the method really does get executed and this point in the code really does get reached), we can single-step through the code and see how the execution progresses. To do this, repeatedly click...
Summary: Inspecting variables is easy – they are automatically displayed in the debugger. When you debug your code, it is important to be able to inspect the state of your objects (local variables and instance variables). Doing it is trivial – most of it you have seen already. You do not need special commands to inspect variables; static variables,...
Summary: Halt and Terminate can be used to halt an execution temporarily or permanently. Sometimes a program is running for a long time, and you wonder whether everything is okay. Maybe there is an infinite loop, maybe is just takes this long. Well, we can check. Call the method longloop() from the Demo class. This one runs a while. Now we want to ...
Learn how to use BlueJ, a Java programming environment designed for teaching at an introductory level. This tutorial covers installation, editing, execution, debugging, applets, libraries and more.
Learn how to use BlueJ, a Java programming environment designed for teaching at an introductory level. This tutorial covers installation, editing, execution, debugging, applets, libraries and more.
Learn how to use BlueJ, a Java programming environment designed for teaching at an introductory level. This tutorial covers installation, editing, execution, debugging, applets, libraries and more.
Learn how to use BlueJ, a Java programming environment designed for teaching at an introductory level. This tutorial covers installation, editing, execution, debugging, applets, libraries and more.
Learn how to use BlueJ, a Java programming environment designed for teaching at an introductory level. This tutorial covers installation, editing, execution, debugging, applets, libraries and more.
Learn how to use BlueJ, a Java programming environment designed for teaching at an introductory level. This tutorial covers installation, editing, execution, debugging, applets, libraries and more.
Learn how to use BlueJ, a Java programming environment designed for teaching at an introductory level. This tutorial covers installation, editing, execution, debugging, applets, libraries and more.
Learn how to use BlueJ, a Java programming environment designed for teaching at an introductory level. This tutorial covers installation, editing, execution, debugging, applets, libraries and more.
Learn how to use BlueJ, a Java programming environment designed for teaching at an introductory level. This tutorial covers installation, editing, execution, debugging, applets, libraries and more.
Learn how to use BlueJ, a Java programming environment designed for teaching at an introductory level. This tutorial covers installation, editing, execution, debugging, applets, libraries and more.
Learn how to use BlueJ, a Java programming environment designed for teaching at an introductory level. This tutorial covers installation, editing, execution, debugging, applets, libraries and more.
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BlueJ is a free Java IDE for teaching object orientation in Java. It helps students learn and transition to a world IDE (NetBeans) with interactive and exploratory features.
Feb 26, 2020 · BlueJ is an open source tool that helps beginners get started with Java programming. It uses color coding, templates, and error tracing to make the language more accessible and understandable.
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BlueJ is a cross-platform IDE for Java and Stride, designed for educational purposes and small-scale software development. It shows the class structure and objects graphically, and allows easy experimentation with object-oriented concepts.
