JAVAMAIL marks all my inbox new messages as open/read

Question

All my new messages in the INBOX (a Domino POP3) are open (or marked as Read) by the following codes:

  props.put("mail.smtp.host", host);
  Session session1 = Session.getInstance(props, null);
  Store store = session1.getStore("pop3");
  store.connect(host,u,p);
  Folder folder = store.getFolder("INBOX");
  folder.open(Folder.READ_ONLY);
  SearchTerm st = new SubjectTerm("Test Javamail");
  Message msg[] = folder.search(st);

  if (1==1) return;

Is it by design?