Serializing Deserializing Object EOFexception

Question

Im getting this exception while deserializing an object:

Output on the console

sending request: GET_OBJS
java.io.EOFException
receiving response
at java.io.ObjectInputStream$PeekInputStream.readFully(Unknown Source)
at java.io.ObjectInputStream$BlockDataInputStream.readUTFBody(Unknown Source)
at java.io.ObjectInputStream$BlockDataInputStream.readUTF(Unknown Source)
at java.io.ObjectInputStream.readUTF(Unknown Source)
at java.io.ObjectStreamClass.readNonProxy(Unknown Source)
at java.io.ObjectInputStream.readClassDescriptor(Unknown Source)
at java.io.ObjectInputStream.readNonProxyDesc(Unknown Source)
at java.io.ObjectInputStream.readClassDesc(Unknown Source)
at java.io.ObjectInputStream.readOrdinaryObject(Unknown Source)
at java.io.ObjectInputStream.readObject0(Unknown Source)
at java.io.ObjectInputStream.readObject(Unknown Source)
at thesis.bot.wab.applet.DApplet.extracted(DApplet.java:218)

I'm trying to deserialize an object without using a file. The object is sent using a DatagramSocket.

From a java applet i call:

sendPacket("GET_OBJS");                 
[...]
input=new ObjectInputStream(new ByteArrayInputStream(receivedPacket.getData()));
objs=extracted(input);
toWrite=Integer.toString(objs.size());
input.close();
sendPacket("PRINT_"+toWrite);
[...]

private LinkedList<Objects> extracted(ObjectInputStream obj)
        throws IOException, ClassNotFoundException {
    return (LinkedList<Objects>) obj.readObject();
}

private void sendPacket(String msg) throws IOException{
        System.out.println("sending request: "+msg);
        buf=msg.getBytes();
        DatagramPacket tosend=new DatagramPacket(buf,buf.length,addr,9999);
        socket.send(tosend);
}

on the other side:

else if(req.compareTo("GET_OBJS")==0){
        Environement env=(Environement) ctx.getService(ctx.getServiceReference(Environement.class.getName()));
        ByteArrayOutputStream baos=new ByteArrayOutputStream();
        ObjectOutputStream out=new ObjectOutputStream(baos); 
        out.writeObject(env.getObjects());
        out.close();
        buf=baos.toByteArray();

        resp="buffer_ready";
    }

where env.getObjects() return a LinkedList of "Objects and Objects is a Serializable class.

What's the problem?

Answer 1

I've modified the code to use tcp socket and Now Im not getting exceptions.

Modified code:

From a java applet i call:

sendPacket("GET_OBJS");                 
[...]
    ObjectInputStream ois=new ObjectInputStream(socket.getInputStream());
    objs=extracted(ois);
    System.out.println(objs.size());
[...]

private LinkedList<Objects> extracted(ObjectInputStream ois)
        throws IOException, ClassNotFoundException {
    return (LinkedList<Objects>) ois.readObject();
}

private void sendPacket(String msg) throws IOException{
    bw.write(msg);
    bw.newLine();
    bw.flush();
    System.out.println("Message sent");
}

on the other side:

else if(req.compareTo("GET_OBJS")==0){
        Environement env=(Environement) ctx.getService(ctx.getServiceReference(Environement.class.getName()));
        ObjectOutputStream out=new ObjectOutputStream(clientSock.getOutputStream());
        out.flush();              
        out.writeObject(env.getObjects());
        out.flush();
        resp="buffer_ready";
    }

Now it works! Thank u for the help!

PS: is necessary that the ObjectOutputStream calls flush() before starting write.