"tom abcdefghi", a little formality: Please change your displayed name to conform with our JavaRanch Naming Policy. We prefer you to use your real name in the form <first name><space><family name>. We usually lock out the accounts with non-conforming displayed names.
Weird but not 100% ilogical. Days and years are numeric, but months are not. Months are an ordered list of names, so we have Jan, Feb and so on, but we end up using their order as well. Since indexes and everything in Java is zero based, so should be the indexes of the months.