Working with Data Entities with Java API for Connected Systems

Hello,

I am working on a connected systems plugin that needs to work with the data entities and storage within Appian. I would like to know whether it is possible to create data entities automatically through the plugin if they don't exist and read the data attributes (not only values) of entities all using the Java API. It is also unclear to me from the documentation where I should even begin to look when working with the Java API, so if someone could point me in the right direction as well, that would be great!

Thanks!