Java JMS和NIO是Java語言中兩種不同的網絡編程模型。Java JMS是Java消息服務的簡稱，是基于消息隊列機制實現的一種分布式通信模式，常用于系統間的異步通信。NIO（Non-blocking I/O）是一種Java I/O操作模型，主要解決傳統阻塞I/O模型在高并發下效率低的問題。

// Java JMS示例代碼
ConnectionFactory connectionFactory = new ActiveMQConnectionFactory("tcp://localhost:61616");
Connection connection = connectionFactory.createConnection();
connection.start();
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
Destination destination = session.createQueue("TEST.QUEUE");
MessageProducer producer = session.createProducer(destination);
TextMessage message = session.createTextMessage("Hello World!");
producer.send(message);
session.close();
connection.close();

在Java JMS中，我們使用Connection、Session、Producer等對象來發送和接收消息。消息發送方將消息發布在Queue或者Topic上，消息接收方從Queue或者Topic上訂閱消息。Java JMS通過這種發布/訂閱機制實現高效的異步通信。

// Java NIO示例代碼
ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
serverSocketChannel.configureBlocking(false);
serverSocketChannel.bind(new InetSocketAddress(8080));
Selector selector = Selector.open();
serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
while (true) {
int readyChannels = selector.select();
if (readyChannels == 0) {
continue;
}
SetselectedKeys = selector.selectedKeys();
IteratorkeyIterator = selectedKeys.iterator();
while (keyIterator.hasNext()) {
SelectionKey key = keyIterator.next();
if (key.isAcceptable()) {
ServerSocketChannel serverSocketChannel = (ServerSocketChannel) key.channel();
SocketChannel socketChannel = serverSocketChannel.accept();
socketChannel.configureBlocking(false);
socketChannel.register(selector, SelectionKey.OP_READ);
} else if (key.isReadable()) {
SocketChannel socketChannel = (SocketChannel) key.channel();
ByteBuffer buffer = ByteBuffer.allocate(1024);
socketChannel.read(buffer);
String request = new String(buffer.array()).trim();
ByteBuffer writeBuffer = ByteBuffer.wrap(("Hello, " + request).getBytes());
socketChannel.write(writeBuffer);
}
keyIterator.remove();
}
}

在Java NIO中，我們使用SocketChannel、ServerSocketChannel、Selector等對象來實現非阻塞I/O操作。其中，Selector是NIO的核心組件，可以將多個通道注冊到一個Selector上，通過監聽Selector上的事件來實現高效的多路復用。

總體來說，Java JMS適用于異步通信場景，具有較好的可靠性和穩定性；Java NIO適用于高并發網絡編程場景，具有更高的I/O效率和處理能力。