It is necessary to rename files when downloading from Cyrillic to Latin. We come to mind the use of switch / case type:
switch (ch){ case 'А': return "A"; case 'Б': return "B"; case 'В': return "V"; case 'Г': return "G"; ..... but as for me it is not a very good example, to unfold a sheet on the whole alphabet. can you tell me how to use the library, for example icu4j or is there something better?