JUnit & JDBC problem

[Paul Ramsden]

I am trying to test some classes which use JDBC connections. The first TestCase to run is able to get a connection for each test it runs, but all later TestCases exit with 'SQLException - No suitable driver'. The tests are being run in batch mode using ANT.
I guess it has something to do with class loading. Perhaps a new class loader for each test?
My test code run in 2 successive Junit tests
reproduces the problem.

public void connect()
{
  try
  {
    log.debug("Connecting..");
    Class c = Class.forName( "COM.ibm.db2.jdbc.app.DB2Driver");
    if(c == null)
      log.error("Class not loaded");
    else
      log.debug("Class loaded");

    StringBuffer sb = new StringBuffer();
    for(Enumeration e = DriverManager.getDrivers(); e.hasMoreElements() ;) 
    {
      Driver d = (Driver)e.nextElement();
      sb.append(d.getClass().getName());
      sb.append(",");
    }
    log.debug("Drivers: " + sb.toString());

    Connection connection =
      DriverManager.getConnection(
        "jdbc :D b2:MVSDB2T",
        "user",
        "pwd");
    log.debug("Connected");
    connection.close();
    connection = null;
    log.debug("Disconnected");
    return;
  }
  catch (ClassNotFoundException e)
  {log.error("", e);}
  catch (SQLException e)
  {log.error("", e);}
  fail("Could not make connection");
}

Does anyone have any ideas?
Paul
[ July 15, 2003: Message edited by: Paul Ramsden ]

[Paul Ramsden]

I have found a way around the problem.
I added fork="yes" to the junit task in ANT.
In spite of that, I would be glad to hear from anyone with insight into class loading in Junit.
Paul

[Simon Brown]

Which test runner are you using? I know people often have problems with the GUI version...

[Paul Ramsden]

ANT is running in text mode, the JUnit task is too.

[Barry Hawkins]

I, too, am experiencing this problem, and setting fork="yes" in my <junit> task is what resolved the issue. I also happen to be using the IBM DB2 Connect JDBC Type 2 driver like you are in the code above. As you know, Type 2 drivers interface heavily with native code on the client. You may find that the "net" driver for DB2 (Type 4, IIRC) works without the fork setting on the <junit> task, as it does not interface with native code libraries. The issue appears to be related to Apache Bug Report #19275: <junit> fails when test classes load native code. Hope this helps some other folks.