WindowListener -> WindowAdapter
removing unused function
changing the location of line
changing class name "Elevator" to "Statement"
Change class name, "Building" to "MainPanel" and "GUI" to "MainFrame".
delete unused function
change static variable to non-static
change class name InputBuffer to JobList
removing BuildingPanel width and height variable
removing not useful elements (getWidth(), getHeight, FloorBtnPanel's ID)
removing ID
floorNumbers are Integrated with FloorBtnsPanel.java
change main And MainFrame, and delete arguments
UI error changed