![]() ![]() An instance of a class is also frequently referred to as an object of that particular class.You should be presented with a drop-down menu as shown in Figure 2. For example, to create an instance of a Circle, place the cursor on the Circle class and right click. The process of creating an instance of a class is called instantiation. This will cause all the classes in the BlueJ window to be compiled. If necessary, you can compile a class by pressing the compile button on the left. Compilation is the process of transforming our computer programs' source code into Java bytecode.We will now create an instance of the Circle class.īefore proceeding, however, one should check if the rectangle representing the Circle class is hatched, which indicates compilation is required. For example, a Circle or Square class and so on. This gives a graphical representation of classes. You should be presented with a window as shown in Figure 4. Navigate to the chapter01 folder within the workspaceBlueJ folder, select and open shapes project(Figure 3). Launch BlueJ using the alias created earlier or otherwise (Figure 2).įrom the BlueJ menu chose Project | Open Project. This should create a folder chapter01 in which are located three subdirectories: lab-classes, picture and shapes.įor the remaining BlueJ labs we should, therefore, progressively build a directory structure as shown in Figure 1. Select the zip file in a file manager (example Finder or Windows Explorer) and unzip it in its present location.Save the file to the workspaceBlueJ/blueJ folder. These projects are in a file named chapter01.zip. Your code will be saved to the sessions directory with subdirectories as shown, one for each lab.ĭownload an archive of Chapter 1 sample projects provided by BlueJ, available here. We suggest you create a folder on your computer named workspaceBlueJ and use this for the entire sequence of upcoming labs.īlueJ sample code will be saved to the blueJ directory. Helpful information on working with files and folders is available here for Windows and here for Mac users. Once setup has completed you may find that creating a shortcut or alias on your desktop helps during the various lab sessions. This ought to install the missing Java infrastructure. If the launch fails this may be because the Java component has not installed properly.Ī fallback method to resolve this is to install Oracle's Netbeans IDE details for which are available here. Any feedback, help, and answers would be much appreciated.Once the installation is complete, launch BlueJ. It's saying things like Package oracle-java8-jdk is not installed. Įrrors were encountered while processing: Processing triggers for hicolor-icon-theme (0.17-2). Processing triggers for desktop-file-utils (0.26-1). Processing triggers for gnome-menus (3.36.0-1). Package libopenjfx-java is not installed.ĭpkg: error processing package bluej (-install):ĭependency problems - leaving unconfigured Package oracle-java8-installer is not installed.īluej depends on libopenjfx-java | oracle-java8-jdk | oracle-java8-installer however: Package oracle-java8-jdk is not installed. ĭpkg: dependency problems prevent configuration of bluej:īluej depends on openjdk-8-jdk | oracle-java8-jdk | oracle-java8-installer however: 205849 files and directories currently installed.) Then I ran sudo dpkg -i b and it outputs this error messages: Selecting previously unselected package bluej. I downloaded the specific version of BlueJ mentioned in the documentation. The output of javac -version is javac 1.8.0_371 indicating that I have Java 8 JDK installed. ![]() I'm using linux OS with Debian 11 distribution. ![]()
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