Do you design before you code? It used to be a best practice to do that, but now with agile development on the rise it seems less people actually do conceptual design as they rather just code as fast as possible.
One nice feature of JDeveloper is that it can make it seem like you actually did conceptual design even if you didn't do it.We can take code that you wrote and make a diagram out of it so you can pretend you modeled things - or in case you need to explain what you did to your managers.
JDeveloper is one of the more powerful free tools out there that offers UML modeling for your code. We do both conceptual modeling - which is not tied to a specific language implementation, and physical modeling of Java code. In the demo below I'm showing how easy it is to start for a set of Java classes that you coded, and transform them into a Java class diagram, then take the physical model and transform it into conceptual UML class diagram, and then take that conceptual model and transform it to another type of physical model - a database model.