John Coleman developed a GPA Calculator Desktop Application using Java and Java Swing, focusing on GUI development within the Michaelkelly71/Acity_CPP_Project repository. He designed and implemented the core logic for GPA calculation, integrating it seamlessly with the user interface to provide real-time results as users entered student details, course information, credit hours, and grades. John established the initial project structure and seeded the repository with foundational files to support future collaboration. He also outlined a persistence layer for saving results to a file or database, though this feature remained under construction. The work demonstrated solid foundational engineering and clear technical direction.