Programs enabling conversion of the file:
If your objective is to convert the file from ARJ to the file 7-Z, you can use any of the applications listed. ARJ to 7-Z conversion process in every program intended for this purpose (so-called converters) is very intuitive and everyone is able to manage converting a file.
However, bear in mind that the list may also include programs to support and work with the indicated extensions ARJ and 7-Z - and not only converters. In such a case, you need to open the source file ARJ and from the options available in the program, choose ”Save as... 7-Z" or "Export to 7-Z".