The calls to getConnection, createStatement and executeQuery can all
throw an SQLException, yet your code does not enclose them in a
try-catch block nor does the method which calls them declare that it
throws an SQLException itself.

Actually, I'm not sure that it's permitted to have the "main" method
declare that it throws exceptions, so your only option is to enclose the
calls to JDBC methods inside a try-catch block:

  try {
    Connection conn = DriverManager.getConnection(DBURL);

    Statement st = conn.createStatement();
    String qry = "select * from aparaty ";
    ResultSet rs = st.executeQuery(qry);
  }
  catch (SQLException sqle) {
    // This code will execute if any of your JDBC methods throws
    // a SQLException.

    // This is *not* the way to handle such an event in production
    // code!
    sqle.printStackTrace();
    System.exit(1);
  }

In production code, you would enclose each JDBC call inside its own
try-catch block, so that your applet can fail in a manner that is both
graceful and appropriate to the error that has occurred.

David Harper
Cambridge, England

"Anna Kubiak" wrote...

Apart from the error you got, I would say there's many more things wrong...
;-)

That error refers to the calls to "rs.next()" and "rs.getString(1)" inside
the method "paint".

And the error says it all.

Either you must enclose those calls in try-catch-block that catches
SQLException, or the method itself must be declared to throw SQLExceptions.

However, you should think more about what actually happens in your code. If
you really want to run it as an applet, you should structure the code to do
what you want in another way than to make use of the "main" method. Even if
you want to run it as an application, you should think again about what it's
supposed to do.

But back to the "erroprs". One rule of thumb I have, is to separate the
calls to the DB from what you do with the data in the application.

As a ResultSet is "connected" to the database, you'll probably run into
several problems when the app leaves the "main" method, with dangling
connections, just because you haven't closed them or the ResultSet.

A simple suggestion to start off with:

Think of the data as "disconnected" from the DB.

Instead of using the ResultSet as an instance field, use another type of
collection, which you populate with the data you want to use.

Then use that collection and its data in the paint-method, instead of using
the ResultSet in it.

// Bjorn A