NIO question: Path.toFile()

[Jonathan Gibbons]

NIO folk,

java.nio.file.Path.toFile() is specified to throw 
UnsupportedOperationException if this Path is not associated with the 
default provider.

UOE seems a somewhat strange choice here. IllegalStateException or a 
custom exception might be seen as more obvious alternatives. (It's also 
somewhat weird that UOE is explicitly documented as being a member of 
the Java Collections Framework.)

So, if there any background rationale of why UOE was chosen here? I'm 
not looking to change the spec for Path.toFile() in any way, but I am 
looking to design a higher level API that may encounter the same 
underlying problem, that a Path may not be associated with the default 
provider.   At my higher level, I need to decide whether to go with UOE, 
just because that is what Path.toFile() does, or whether to convert it 
into some other exception.

-- Jon