This week's book giveaway is in the Spring forum. We're giving away four copies of Pro Spring MVC with WebFlux: Web Development in Spring Framework 5 and Spring Boot 2 and have Marten Deinum & Iuliana Cosmina on-line! See this thread for details.
This example shows how an X/Y chart with two curves can be created using the JFreeChart package. It is both saved to a file and displayed in a window. The part that's commented out creates a bar chart instead.