Improving java file i/o performance when using a mapped network drive on Windows

We've created a java application that (among other things) uses the built-in file IO libraries to acc开发者_StackOverflow社区ess 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?

You haven't said which version of windows you're using but it's well-acknowledged that early versions of SMB have performance issues. In a nutshell: later (e.g. Windows Server 2012) = better when it comes to performance, although you need to ensure that both the client and server are working on the latest version of SMB for maximum performance.