public JDBCXYDataset(String url,String driverName,String user,String password) throws SQLException, ClassNotFoundException {
  this();
  Class.forName(driverName);
  this.connection=DriverManager.getConnection(url,user,password);
}

public JDBCXYDataset ( String url , String driverName , String user , String password ) throws SQLException , ClassNotFoundException { this ( ) ; Class . forName ( driverName ) ; this . connection = DriverManager . getConnection ( url , user , password ) ; }
creates a new dataset ( initially empty ) and establishes a new database connection .
