Sending messages back and forth is at the core of instant messaging. Although individual messages can be sent and received as packets, it's generally easier to treat the string of messages as a chat using the org.jivesoftware.smack.Chat class.

Chat

// Assume we've created an XMPPConnection name "connection". 
ChatManager chatmanager = connection.getChatManager();
Chat newChat = chatmanager.createChat("jsmith@jivesoftware.com", new MessageListener() {

    public void processMessage(Chat chat, Message message) {
        System.out.println("Received message: " + message); 
    } 
}); 
try {
    chat.sendMessage("Howdy!"); 
} catch (XMPPException e) {
    System.out.println("Error Delivering block");
}

The Chat.sendMessage(String) method is a convenience method that creates a Message object, sets the body using the String parameter, then sends the message. In the case that you wish to set additional values on a Message before sending it, use the Chat.createMessage() and Chat.sendMessage(Message) methods, as in the following code snippet:

Message newMessage = newChat.createMessage();
newMessage.setBody("Howdy!");
message.setProperty("favoriteColor", "red");
newChat.sendMessage(newMessage);

You'll also notice in the example above that we specified a MessageListener when creating a chat. The listener is notified any time a new message arrives from the other user in the chat. The following code snippet uses the listener as a parrot-bot -- it echoes back everything the other user types.

 // Assume a MessageListener we've setup with a chat.

    public void processMessage(Chat chat, Message message) {
        // Send back the same text the other user sent us.
        chat.sendMessage(message.getBody());
    }