sun.nio.fs.WindowsPath::getPathForWin32Calls synchronizes on 'path' field, which is a String object:

        if (type != WindowsPathType.DRIVE_RELATIVE) {
            synchronized (path) {
                pathForWin32Calls = new WeakReference<String>(resolved);
            }
        }

this might lead to a deadlock, this code should synchronize on "this".