Not really, the interface signatures need to be the same for normal Java code to work. There's only one way to write the interfaces, code would be identical eve

Not really, the interface signatures need to be the same for normal Java code to work. There's only one way to write the interfaces, code would be identical even reverse engineered. This is the same as writing an S3 compatible java client. If you want to be able to substitute one directly for another, the method signatures have to be the same even if all the implementations are different. This also mirrors how kernel interfaces work. Xen, GVisor, and many others implement the exact same kernel interfaces as Linux because they have to to work. If the API was copyrightable any contributor that designed one of these interfaces could prevent these projects from existing