Select element and its descendants - xpath

Question

I'm trying to select an folder and its descendants from a JCR with XPath. I can select the folder easily enough:
//content/documents/folder-name
I can select its descendants too:
//content/documents/folder-name//*
However, I can't figure out how to get both. I've tried several things. These select nothing:
//content/documents/folder-name | //content/documents/folder-name//*
//content/documents/folder-name(. | *)
//content/documents/folder-name/(. | *)
//content/documents/folder-name/descendant-or-self
//content/documents/folder-name/descendant-or-self::node()
These both throw a javax.jcr.query.InvalidQueryException:
//content/documents/folder-name[. | *]
//content/documents/folder-name/[. | *]
Obviously I'm terrible at XPath. Please help.
Edit: I was using the // prefix because I didn't realize I could use /jcr:root/content instead. I have the same problem with that, however.

Answer 1

You can combine two XPaths using the union operator:
xpath1 | xpath2
However, your first XPath,
//content/documents/folder-name
does select the folder-name element(s), which includes the descendants of the element.
If you want the folder-name elements to be first in a list, followed by their descendants, you could combine as follows:
//content/documents/folder-name | //content/documents/folder-name//*

Answer 2

//content/documents/folder-name/descendant-or-self::node() looks correct to me (without seeing your XML input), though //content/documents/folder-name/descendant-or-self::* is probably better.
Certainly if //content/documents/folder-name selects something then ``//content/documents/folder-name/descendant-or-self::*` should also select something.
In XPath 2.0 you can do //content/documents/folder-name/(.|descendant::*) but although it's shorter, it seems clumsier to me than using the descendant-or-self axis.