Post requests in java

requests.java

import java.io.*;
import java.net.*;
import javax.swing.*;

public class Requests {
    static String domain;


    static URL myurl;
    static URLConnection myurlc;
    static OutputStreamWriter osr;
    static BufferedReader br;
    static String line;
    static String resp;
    static StringBuilder sb;


    public Requests(String d) {
        domain = d;
    }

    public String sendPost(String data) {
        try {
            sb = new StringBuilder();
            myurl = new URL(domain);
            myurlc = myurl.openConnection();
            myurlc.setDoOutput(true);
            osr = new OutputStreamWriter(myurlc.getOutputStream());
            osr.write(data);
            osr.flush();

            br = new BufferedReader(new InputStreamReader(myurlc.getInputStream()));
            while((line = br.readLine()) != null)
            {
                sb.append(line);
            }
            br.close();
            osr.close();
        }
        catch(IOException e)
        {
            JOptionPane.showMessageDialog(null,"IO Error");
        }
        finally {
            return sb.toString();
        }
    }
}