file.hidden — Is the file hidden?
Return 1 if the file is "hidden". To quote from the relevant Java documentation:
The exact definition of hidden is system-dependent. For example, on UNIX systems a file is considered to be hidden if its name begins with a period character ('.'). On Win32 and FAT file systems, a file is considered to be hidden if it has been marked as such in the file's attributes. If hidden files are not supported on the referenced file system, this method always returns false.