以下是一个简单的示例代码，演示了如何在Android平台上使用UDP打洞。

import java.io.IOException;
import java.net.*;

public class UdpHolePunching {
    public static void main(String[] args) throws IOException {
        // 创建两个UDP套接字
        DatagramSocket clientSocket1 = new DatagramSocket();
        DatagramSocket clientSocket2 = new DatagramSocket();

        // 获取本地IP地址和端口号
        InetAddress localAddress = InetAddress.getLocalHost();
        int port1 = clientSocket1.getLocalPort();
        int port2 = clientSocket2.getLocalPort();

        // 创建两个线程分别用于发送和接收UDP数据包
        Thread senderThread = new Thread(() -> {
            try {
                // 向服务器发送包含本地IP地址和端口号的数据包
                byte[] sendData = (localAddress.getHostAddress() + ":" + port1).getBytes();
                DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, InetAddress.getByName("server-ip"), 12345);
                clientSocket1.send(sendPacket);
                System.out.println("Sent packet to server: " + new String(sendData));
            } catch (IOException e) {
                e.printStackTrace();
            }
        });

        Thread receiverThread = new Thread(() -> {
            try {
                byte[] receiveData = new byte[1024];
                DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);

                // 接收服务器发送的数据包，其中包含了另一方的IP地址和端口号
                clientSocket2.receive(receivePacket);
                String receivedInfo = new String(receivePacket.getData(), 0, receivePacket.getLength());
                System.out.println("Received packet from server: " + receivedInfo);

                // 解析IP地址和端口号
                String[] info = receivedInfo.split(":");
                InetAddress remoteAddress = InetAddress.getByName(info[0]);
                int remotePort = Integer.parseInt(info[1]);

                // 向另一方发送数据包
                byte[] sendData = "Hello from client 2".getBytes();
                DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, remoteAddress, remotePort);
                clientSocket2.send(sendPacket);
                System.out.println("Sent packet to client 1: " + new String(sendData));
            } catch (IOException e) {
                e.printStackTrace();
            }
        });

        // 启动发送和接收线程
        senderThread.start();
        receiverThread.start();
    }
}

请注意，此代码只是一个简单示例，仅用于演示UDP打洞的基本概念。在实际应用中，可能需要更复杂的逻辑来处理网络连接和数据传输。