JavaWiz

JavaWiz is a visualization VSCode plugin for Java programs targeted at programming beginners. Users can step through the program line by line and follow the execution in the visualization panel. At the moment it provides two visualizations:

• The "desk test" displaying the changes from line to line, which is useful for understanding simple algorithms, and
• a simplified stack and heap visualization, which helps to understand how program memory works.

JavaWiz is developed and maintained by the Institute for System Software, Johannes Kepler University Linz, Austria.

How to use

The extension requires at least JDK 17 to run. After installing JavaWiz from the VSCode marketplace and opening a .java file, the tool can be started by:

• clicking Run in JavaWiz above the main method,
• using the shortcut CTRL + SHIFT + J, or
• right click into the opened editor and selecting Run in JavaWiz from the context menu.

The left/right arrow buttons in the visualization panel can then be used to navigate through the program and the yellow arrow will restart the program. It is possible to step back and repeat parts of the program, so there's no need to restart if the user has gone too far, but input will be not repeated. The current status ("live" or "replay") is also displayed in the toolbar. A similar explanation of the user interface can be accessed by clicking on the Help/question mark button.

Please note that the tool is targeted at beginners and still under development, so not all language features of Java might be supported. For didactic reasons, certain code completion features are deactivated - they can be reactivated in the VS Code settings.