public String beginDownloadConnection(
  Timestamp ts, 
  String user )
  throws java.sql.SQLException 
{  
    doSomeWork( ts, user );
    return( "CALL do_some_sql( {ml s.last_download}, {ml s.username} )" );
}

public void beginDownloadConnection(
  Timestamp ts, 
  String user )
  throws java.sql.SQLException 
{  
    doSomeWork( ts, user );
    
    Connection conn = DBConnectionContext.getConnection();
    PreparedStatement stmt = conn.prepareStatement( "CALL do_some_sql( ?,? )" );
    stmt.setTimestamp( 1, ts );
    stmt.setString( 2, user );
    stmt.executeUpdate();
}