You have to know the basics principles of Graphics on Java to understand what is happening and can use the libraries like: JFrame, JPanel and methods and attributes of this components. and controlling ...
☕ The Definitive Advanced Java & Spring Enterprise Master Suite: Interactive Web IDE, 153+ runnable source files, and blueprints covering Swing, Applets, JDBC, Sockets, Java NIO, Servlets, RMI, JSP, ...