A resultset is stored in memory - I'm unsure what you mean about
"offline". To get all of the columns, ask for all of the columns.

A simple resultset example:

java.sql.Connection c = DriverManager.getConnection("your driver and
path to db", "your db user id", "your db password");
Statement get = c.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
                          ResultSet.CONCUR_READ_ONLY);
ResultSet rs = get.executeQuery("your query");

//use your result set from here