Hi Dan,

It seems these pointers are actually marshaled for the thread other then thread where OleMessageLoop works. To workaround this, you should use COM marshaling functions:

   // This method receives interfaces from VB code
    public void TestProfile(_DriverProfile driverProfile) {
        try {
            // Create stream to marshal interface
            IStream strm = OleFunctions.coMarshalInterThreadInterfaceInStream(new IUnknownImpl(driverProfile));
            TestDialog dlg = new TestDialog(strm); // Pass this stream to dialog
            dlg.setVisible(true);                                    
        } catch (Throwable th) {
            th.printStackTrace();
            JOptionPane.showMessageDialog(null, th.getMessage());
        }
    }

public class TestDialog extends javax.swing.JDialog {
    private IStream stream; // Stream is stored in the dialog
 
    /** Creates new form TestDialog */
    public TestDialog(IStream stream) {
        super((javax.swing.JDialog)null, true);
        initComponents();
        this.stream = stream;
    }

private void btnTestActionPerformed(java.awt.event.ActionEvent evt) {
    ComFunctions.coInitialize(); // Initialize COM
    IUnknownImpl unk = new IUnknownImpl();
    stream.seek(new Int64(0l), new StreamSeek(StreamSeek.STREAM_SEEK_SET)); // Set Stream pointer to the beginning
    OleFunctions.coUnmarshalInterface(stream, new IID(_DriverProfile.INTERFACE_IDENTIFIER), unk); // Unmarshal interface
    _DriverProfile profileProxy = new _DriverProfileImpl(unk); // Call QI
    System.out.println(profileProxy.getDriverName()); // It works now.
}

In this sample unmarshaling performed each time btnTestActionPerformed called. For performance reasons, this can be performed only once per thread, in this case unmarshaled pointer can be stored permanently (in thread local memory, for example). I did not included this in code to keep it simple.

Regards,

Vadim Ridosh