Use the new DateTimeFormatter to parse and format YearMonth directly and use Locale to set the locale you need.
Don't use SimpleDateFormat. That is part of the old Date API.
Try running the code to see if this is what you want in Codiva online compiler IDE.
YearMonth yearMonth = YearMonth.of(2016, 7);
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy MMMM",
new Locale("it", "IT"));
System.out.println(yearMonth.format(formatter));
Full working code in Codiva.