We've created a java application that (among other things) uses the built-in file IO libraries to access a list of files inside a particular folder on a network share. When the folder is specified as a local file (e.g., c:\foobar), performance is fine. However, if we map a network drive to the folder, even if the folder is on the same machine (e.g., z:\ -> c:\foobar), performance goes through the floor. Any ideas on what might be causing the problem? More importantly, any suggestions on how to improve the situation?