post twitter through proxy using single java program

package neoe;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Authenticator;
import java.net.PasswordAuthentication;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;

import sun.misc.BASE64Encoder;

public class TwitterPost {
public static class httpAuthenticateProxy extends Authenticator {
protected PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication("proxyuser","proxypass".toCharArray());
}
}
public static void main(String[] args) throws IOException {
Authenticator.setDefault( new httpAuthenticateProxy());
String msg="test message";
String user="twitterUser";
String pass="twitterPass";
URL url = new URL("http://twitter.com/statuses/update.json");
URLConnection conn=url.openConnection();
conn.setDoOutput(true);
conn.setDoInput(true);
conn.setRequestProperty("Authorization", "Basic "+new BASE64Encoder().encode((user+":"+pass).getBytes()));
OutputStream out=conn.getOutputStream();
out.write(("status=" + URLEncoder.encode(msg, "UTF-8")).getBytes());
out.flush();
InputStream in =conn.getInputStream();
int c;
System.out.println("response begin---");
while((c=in.read())!=-1){
System.out.print((char)c);
}
System.out.println("\nresponse end---");

}

}

run with param
-Dhttp.proxyHost=yourproxyhost -Dhttp.proxyPort=yourproxyport