We should add @Override here, because it now implements abstract method.
Oh, thanks, I forgot this.
I think we use the same FileDescriptor, so we also don't need to close the slices?
Slices are just like clones. So for example CFSDirectory holds an input over the entire .cfs file, and when you ask to open a "file" within the cfs it returns a slice (clone) of it. when you close the cfs it closes the real one.
In ByteBufferIndexInput.slice() the return value is a package-protected class, so we should change this to the general IndexInput like in the abstract base class, otherwise the Javadocs will be look broken.
What javadocs? This is not a public class