Maildir is not visible

OK, this is probably another newbie question, but let me try.
I have this testing program to copy all messages from one mbox
folder to another maildir one:

import java.util.Properties;
import javax.mail.*;
import gnu.mail.providers.maildir.*;

public class CopyFolder {

    /**
     * @param args
     * @throws Exception
     */
    public static void main(String[] args) throws Exception {
        // TODO Auto-generated method stub
        String urlStr = "/home/matej/.eclipse/workspace"+
            "/kmail2tbfolders/examples/";
        Session session = Session.getInstance(new Properties());
        session.setDebug(true);
        URLName storeURL = new URLName("mbox://"+urlStr);
        Store mboxStore = session.getStore(storeURL);
        mboxStore.connect();
        Folder mboxFolder = mboxStore.getDefaultFolder();
        mboxFolder = mboxStore.getFolder("test");
        mboxFolder.open(Folder.READ_WRITE);
        
        URLName store2URL = new URLName("maildir://"+urlStr+"/output/");
        Store maildirStore = session.getStore(store2URL);
        Folder targetFolder = new MaildirFolder(maildirStore, "target");
        if (targetFolder.create(Folder.HOLDS_MESSAGES)) {
            targetFolder.open(Folder.READ_WRITE);
            Message[] messages = mboxFolder.getMessages();
            Message[] messagesToGo;
            for (int i=0;i<messages.length;i++) {
                boolean success = messagesToGo.add(messages[i]);
            }
            targetFolder.appendMessages(messagesToGo);
        }
        mboxStore.close();
        maildirStore.close();
    }

}

When I try to compile this with gcj (4.1.1. compatible with Java
1.4) I get these error messages:

[matej@chelcicky kmail2tbfolders]$ javac CopyFolder.java
----------
1. ERROR in CopyFolder.java (at line 25)
        Folder targetFolder = new MaildirFolder(maildirStore, "target");
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The constructor MaildirFolder(Store, String) is not visible
----------
2. ERROR in CopyFolder.java (at line 31)
        boolean success = messagesToGo.add(messages[i]);
                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Cannot invoke add(Message) on the array type Message[]
----------
2 problems (2 errors)[matej@chelcicky kmail2tbfolders]$

Does anybody have any idea, what's going on here? There is
MaildirFolder imported above, so it should be available (and
apparently eclipse doesn't have any problems with the idea), but
it isn't. The second is how can I add messages to the final
Message[] array which could be then sent to appendMessages?

Thanks,

Matej Cepl