Using IntelliJ IDEA Community Edition with unfamiliar, complex Java CodeI

I'm new to both Java & IntelliJ & recently inherited some very old, complex Java code. Does IntelliJ have a flowcharting feature? I really need some way to get an overview of the code. Or is there a plug-in or some other (preferably free) software that could help me see how the pieces of code relate to each other? I would appreciate any suggestions that you might have.