StreamCorruptedException: trying to transmit objects per bytearray (UDP)

Question

Hello Community,
For a school project I'm trying to send Objects over a UDP package, but every time I try to do so the following error occures:
"StreamCorruptedException: invalid stream header: 53617420 (in java.io.ObjectInputStream)"
The code for "UDP_OUTGOING":
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.*;
import java.util.*;
import java.io.*;
class UDP_OUTGOING implements Serializable
    byte[] raw;
    public void transformToBytes(HERO hero) throws IOException, InterruptedException
        ByteArrayOutputStream buffer = new ByteArrayOutputStream();
        ObjectOutputStream out = new ObjectOutputStream(buffer);
        out.writeObject(hero);
        out.close();
        buffer.close();
        raw = buffer.toByteArray();
    public void sendData (String address) throws IOException, InterruptedException
        InetAddress ia = InetAddress.getByName( address );
      String s = new Date().toString();
      byte[] raw = s.getBytes();
      DatagramPacket packet = new DatagramPacket( raw, raw.length, ia, 4711 );
      DatagramSocket dSocket = new DatagramSocket();
      dSocket.send( packet );
      System.out.println( "Package sent!" );
} And here is the code for "UDP_INCOMING":
import java.io.IOException;
import java.net.*;
import java.io.Serializable;
import java.io.ByteArrayInputStream;
import java.io.ObjectInputStream;
public class UDP_INCOMING implements Serializable
    private boolean check = true;
    HERO hero;
    public HERO getData() throws IOException, ClassNotFoundException
        DatagramSocket socket = new DatagramSocket( 4711 );
        while ( check )
            // WAITING FOR PACKAGE
            DatagramPacket packet = new DatagramPacket( new byte[1024], 1024 ); //1024...Is this the problem maybe?
            socket.receive( packet );
            // READING PACKAGE
            byte[]      data    = packet.getData();
            ByteArrayInputStream bis = new ByteArrayInputStream(data);
            ObjectInputStream ois = new ObjectInputStream(bis);
            hero = (HERO) ois.readObject();
            ois.close();
            check = false;
        return hero;
  public void pauseGetData()
      check = false;
  public void startGetData()throws IOException, ClassNotFoundException
      check = true;
      this.getData();
} I hope you can help me,
Regards,
Karl

Answer 1

Your code using ObjectOutputStream is correct but you aren't using it. You're sending Date.toString() and you're trying to read it with an ObjectInputStream. Send the date with ObjectOutputStream.writeObject().