Java client on local machine update database on server

Hi,

I'm doing a project where I will have a java GUI on a clients machine and I
want it to have the ability to receive input from a user and then update a
postgresql database (but wouldn't have to be straight away). I can currently
think of two ways of doing this:

Firstly turn the user input to a set of SQL statements and save into a text
file and then create a transaction that will connect to the database on the
server and execute them all.

Probably an easier way would be to have a copy of the database on the
clients machine and copy the database to the server every night or so.

Would either of these ideas work? Which seems less crazy? Is there an easier
way?

Thanks in advance for the help. Apologies in advance for being such a
novice.

Kieran Tarestad