Unable to re-use entity resolver

[Wong Kok Wai]

When I parse two documents that uses the same DTD consecutively, and I
use the same instance of my implementation of EntityResolver, a "stream
closed" exception is thrown. The workaround is to create a new instance
for each document. This is rather inefficient as the same DTD is used
and one instance of entity resolver implementation is sufficient IMHO.
Is this a feature or a bug?