jodd-mail/src/main/java/jodd/mail/ReceiveMailSession.java
public Folder getFolder(final String folder) {
		try {
			return getService().getFolder(folder);
		} catch (MessagingException e) {
			throw new MailException("Folder not found: " + folder, e);
		}
	}
public Folder getFolder(final String folder) {
		try {
			return getService().getFolder(folder);
		} catch (MessagingException e) {
			throw new MailException("Folder not found: " + folder, e);
		}
	}
Just returns a folder, w/o opening.