File.separator used in a regular expression

In class org.infinispan.util.ClassFinder , method toClassName(String fileName) is using File.separator in a regular expression; on Windows this is going to be given the value "\" which is an escape character in a regular expression.
(found by findbugs, apparently nobody here is testing on Windows)
Findbugs suggest to replace it with

File.separatorChar=='
' ? "\\\\" : File.separator