Writing Java Programs using BlueJ
Writing Java Programs using BlueJ
Embedded Files
First download and install BlueJ, a java IDE, from https://bluej.org/
First download and install BlueJ, a java IDE, from https://bluej.org/
1. Create a folder/directory using your system file manager. This should be a local folder on your machine. It is recommended that you put it in your home directory. Name the folder Java Programs or something similar.
2. Start BlueJ and select Create a new project.
In BlueJ's top menu bar, select Project and New.... to get the New Project Dialog. In Look In box, find and select the folder that you created in Step 1. This may require you to go up/down the directory tree a few times. Enter the name of the project (enter "YourProjectName") in File name and click on Create. Don't use spaces in the project name.
3. The Project Display Area to the middle right should turn white, and an icon that looks like a piece of paper should appear.
4. Create a new class.
Click on the button New Class... to obtain the Create New Class Dialog. Enter "YourProjectName" in the Class Name textbox, and make sure that the Class radio button is selected. Then click on the OK button.
5. Open the editor for the class.
A yellow icon with the lable HelloWorld and diagonal lines should appear.Double click on the yellow HelloWorld icon to open the editor for that class.
6. Modify the code for the class.
When you open the Class, you will see some sample code for the class, including an instance variable x, a constructor HelloWorld, and the method named sampleMethod. This code may be interesting the first time you see it, but it is not necessarily what you need. You might have to select all of the code and delete it. Then add your code. For example, the HelloWorld program would be:
7. Compile the class.
Click on the Compile button at the top of the editor. You should get the message "Class compiled - no syntax erors."
8. Run the application.
Go back to the main BlueJ window. If you don't see it on the desktop screen, look at the bottom of the monitor screen -- there are two BlueJ windows. Then, right click on the yellow HelloWorld icon, and select void main(args) to run the main method.
You will get the Method Call Dialog. Since you don't have any command line arguments for this method, simply click on OK.
Note: If your program (or method) takes arguments and you want to enter them, type in values separated by commas.
You will get the Terminal Window with the message "Hello, world!"
You now have created a Java program on your computer's local IDE. Save your program before you close it.
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