要实现Android和Java的Ping/Pong网络套接字功能，可以使用Java的Socket类和Android的AsyncTask类来实现。

首先，创建一个名为PingPongServer的Java类，用于创建服务器套接字并监听来自客户端的Ping请求。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class PingPongServer {
    private ServerSocket serverSocket;
    private Socket clientSocket;
    private BufferedReader in;
    private PrintWriter out;

    public void start(int port) {
        try {
            serverSocket = new ServerSocket(port);
            clientSocket = serverSocket.accept();

            in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
            out = new PrintWriter(clientSocket.getOutputStream(), true);

            String inputLine;
            while ((inputLine = in.readLine()) != null) {
                if (inputLine.equals("Ping")) {
                    out.println("Pong");
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                in.close();
                out.close();
                clientSocket.close();
                serverSocket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        PingPongServer server = new PingPongServer();
        server.start(1234);
    }
}

接下来，创建一个名为PingPongClient的Java类，用于创建客户端套接字并发送Ping请求。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

public class PingPongClient {
    private Socket socket;
    private BufferedReader in;
    private PrintWriter out;

    public void start(String ip, int port) {
        try {
            socket = new Socket(ip, port);

            in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            out = new PrintWriter(socket.getOutputStream(), true);

            out.println("Ping"); // 发送Ping请求

            String response = in.readLine();
            System.out.println("Response: " + response); // 打印Pong响应

            in.close();
            out.close();
            socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        PingPongClient client = new PingPongClient();
        client.start("localhost", 1234);
    }
}

在Android项目中，创建一个名为PingPongTask的AsyncTask类，用于在后台线程中执行Ping请求。

import android.os.AsyncTask;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

public class PingPongTask extends AsyncTask {
    private String ipAddress;
    private int port;

    public PingPongTask(String ipAddress, int port) {
        this.ipAddress = ipAddress;
        this.port = port;
    }

    @Override
    protected String doInBackground(Void... voids) {
        try {
            Socket socket = new Socket(ipAddress, port);

            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);

            out.println("Ping"); // 发送Ping请求

            String response = in.readLine();

            in.close();
            out.close();
            socket.close();

            return response;
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
    }

    @Override
    protected void onPostExecute(String response) {
        if (response != null) {
            // 处理Pong响应
        } else {
            // 处理错误情况
        }
    }
}

要在Android应用程序中使用PingPongTask类，可以在某个地方调用它的execute方法。

PingPongTask task = new PingPongTask("localhost", 1234);
task.execute();

以上就是实现Android和Java的Ping/Pong网络套接字功能的解决方法，其中包含了相关代码示例。