In this thread on derby-dev, http://email@example.com%3e,
it was mentioned that RAFContainer4 calls padFile() when creating a container. Since padFile() uses old I/O calls and the rest of RAFContainer4 uses NIO, it could possibly cause similar issues as those seen in
DERBY-3347. Although we haven't verified that this is a problem, we should try to avoid mixing old I/O and NIO to be on the safe side.