How do I update a TIMESTAMP column of a MYSQL table with the current date and time in Java

I am trying to update a TIMESTAMP column of a MYSQL table with the current date and time in Java code.

String sqlString = "SELECT * FROM table WHERE ..." ;
        Statement st = con.createStatement( ResultSet.TYPE_SCROLL_INSENSITIVE,
                ResultSet.CONCUR_UPDATABLE ) ;
        ResultSet rs = st.executeQuery(sqlString) ;
        rs.first();
        rs.updateInt("status", STATUS_OPTED_OUT) ;
???---what would go here for a column "update_time" ?
        rs.updateRow();

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