move (copy) IMAPMessage to another folder on the mail server

        List<Message> tempList = new ArrayList<>();
        tempList.add(myImapMsg);
        Message[] tempMessageArray = tempList.toArray(new Message[tempList.size()]);
        fromFolder.copyMessages(tempMessageArray, destFolder);

It is a bad idea to move a message with methods like copyMessages(), addMessages() or appendMessage() and removing the old message, because these methods generates a new message. The new message have an different Message-ID in the header. If you response on the new message, the receiver cannot relate the response to his sent mail, because he does not know the new Message-ID. You have to cast the folder to a IMAPFolder. IMAPFolder has the method moveMessages(Message[] msgs, Folder targetFolder) to move messages without tampering the header Message-ID.

Presumably you're already using a com.sun.mail.imap.IMAPFolder?

That class has the method addMessages(Message[] msgs). Use it to add a Message to the new folder.

Alternatively, as mentioned by @gospodin, there's a copyMessages(Message[] msgs, Folder destinationFolder) method, which provides a shortcut for copying messages from their original folder to a new one.