Introduction of BlueJ

BlueJ is a windows based platform for Java Development Kit (JDK). It is a free Java environment started in 1999 by Michael Kolling and John Rosenberg at Monash University, Australia, as a successor to Blue. It requires to install JDK version 1.3 or more before installing BlueJ. It can be freely downloaded from its official website of BlueJ. It was developed to support learning and teaching of OOPs(object-oriented programming). The objects can be interactively created and tested. It is a simple user interface, BlueJ has a simpler interface than most professional IDEs. It offers many tools that are specific to its educational goals. There are also standard development tools available, such as an editor, compiler and runtime environment. Features of BlueJ : Some of the features of BlueJ are:

• The tasks can be performed more conveniently.
• It shows you a sample program to give a brief idea of programming.
• Debugging is easy as it indicates errors at bottom of screen.
• It is a simpler interface than any other IDE.
• It has some new features which are not seen in any other IDE.
• BlueJ can run on Windows, MacOS, Linux or any platforms which runs java.
• It allows you to interact with objects.

How to install BlueJ ? Make sure you have JDK installed first before downloading and installing BlueJ otherwise it will not work.

1. Go to official page of BlueJ, click on link based on your preference whether it is Windows, Mac Os, or Linux.
2. BueJ setup box will appear, click on Next.
3. On next page, click on Next.
4. Then click Install and Finish.

How to start BlueJ ?

1. Double click BlueJ icon available on desktop to start Java.
2. The BlueJ window will appear on your screen.
3. The screen shows ‘Project’ on top left corner. It is creation of folder that contains various BlueJ classes.
4. Click on it and select ‘New Project’ from drop-down menu.
5. Enter file name (for example, Sample) and finally click on create button.
6. The project folder created with Sample name is created and is shown on your screen.
7. Now, click ‘New Class’ suppose named ‘welcome’ and enter class name in text box.
8. Finally, click OK to create class icon. (Class name is basically program name where your program is saved on hard disk).
9. On double clicking icon, ‘welcome’, sample program is displayed
10. Then, to write your program, delete sample program available on window.
11. Then, type your program.
12. After completion of your program, click on ‘compile’ button.
13. If your program is error free then message will appear on screen at bottom pane as ‘Class Compiled- no syntax errors’. Now, you are ready to execute program.

Execution of a program :

1. After successful compilation of program, select class icon and click right-handed mouse button. A drop-down menu appears. Select and click option void main(String args[]).
2. A “Method Call” window appears on screen, click OK.
3. Then, desired output will be shown on next screen.

Supported Languages : Java and Stride both languages are supported by BlueJ. Java support has been provided in BlueJ since its inception, while Stride support was added in 2017. BlueJ now uses Java 11+, which requires 64-bit operating system which 95+% users will have. For 32-bit operating system download BlueJ 4.1.4. instead.