Many thanks Martin!  I downloaded mstor and with the little program below
was able to successfully browse through my emails.  the jars mbox.jar,
activation.jar and mail.jar are needed.  This code runs on my sun box, which
is running SunOS 5.9.  I am off and running - thanks!

package com.xxx.yyy.mstore;
import java.io.*;
import java.util.*;
import javax.mail.*;
public class Mstor {
   public static void main(String[] args) {
       Session session = Session.getDefaultInstance(new Properties());
       try {
           Store store = session.getStore(new URLName("mstor:/var/mail"));
           store.connect();
           //
           // read messages from Inbox..
           Folder inbox = store.getDefaultFolder().getFolder("user01");
           inbox.open(Folder.READ_ONLY);
           Message[] messages = inbox.getMessages();
           System.out.println(messages.length);
           try {
               for (int i=0, n=messages.length; i<n; i++){
                   System.out.println(i + ": " + messages[i].getFrom()[0] +
"\t" + messages[i].getSubject());
                   messages[i].writeTo(System.out);
               }
           } catch (IOException ioe) {
               ioe.printStackTrace();
           }
           inbox.close(false); // expunges all deleted messages if this
flag is true
           store.close();
       } catch (MessagingException me) {
           me.printStackTrace();
       }
   }
}