When passed a File for something with a UNC path (e.g. \\127.0.0.1\shared), FileSystemContext.getFileURI() return a URI like "file://127.0.0.1/shared" (which is what Windows itself uses) rather than "file:////127.0.0.1/shared" (which Java uses, and converts for OS calls). This will cause JBoss to fail to deploy things if they are located on an unmapped UNC location.

I'm attaching a test case for this. To use it, you need to run it on a Windows system and have access to a something with a UNC path. The code as written expects there to be a SMB share called "shared" on the machine it is run on, but it can easily be change to point elsewhere.