can't parse dd/mm/yyyy in Italy locale with java 9 or above

Steps to Reproduce

1. run keikai with Java 9 or above
2. load a blank sheet in a browser in *Italy* language
3. enter 20/2/2020 , format dd/mm/yyyy

Current Result

keikai doesn't turn it into a date value, it's still a text

Expected Result

keikai turns it into a date value

Debug Information

1. if you run keikai in Java 8, keikai works as expected
2. zss doesn't have this issue
3. DateInputMask.getDate41() return different result between Java 8 and java 9 or above
4. even run Java 9 or above with -Djava.locale.providers=COMPAT still can work under Italy locale
5. happened after fixing KEIKAI-379

Workaround

run in Java 8