Bytebuffer to byte array and Object streams

Hello

I am trying to send objects through a bytebuffer and have a server
that uses NIO for this, and a threaded client.

The clients sents the object ok, but the server throws this exception:

java.io.StreamCorruptedException: invalid stream header

In the function that calls the method to read the object sent.

Dato dato = new Dato();

ByteBuffer bb = ByteBuffer.allocate(TAMANYO_BUFFER);
....
 dato = leerDeBytes(aArray(bb));

The class sent is an object of type Dato, wich is my custom object.
This is the class:

/*
 * Dato.java
 *
 */

package hiperia.Browser3d;

import java.io.Serializable;

public class Dato implements Serializable {
    public String textoChat = null;
    public float f = 0.0f;
    // constructor of class Dato
    public Dato() {
    }

}

And these are the functions called in the server that send the
exception:

public static byte [] convertirABytes (Object objeto) throws
IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ObjectOutputStream os = new ObjectOutputStream(baos);
        os.writeObject (objeto);
        os.flush();
        os.close();

        byte [] array = baos.toByteArray();
        baos.close();
                return array;
    }

     private byte[] toArray(ByteBuffer buffer) {

        byte[] array = new byte[buffer.limit() - buffer.position()];

        if (buffer.hasArray()) {
            int offset = buffer.arrayOffset();
            byte[] bufferArray = buffer.array();
            System.arraycopy(bufferArray, offset, array, 0, array.length);

            return array;
        } else {
            buffer.get(array);
            return array;
        }
    }

     private byte[] aArray(ByteBuffer buffer) {

    // Retrieve all bytes in the buffer
    buffer.clear();
    byte[] bytes = new byte[buffer.capacity()];
    buffer.get(bytes, 0, bytes.length);
    return bytes;
     }

     public static Dato leerDeBytes(byte[] bytes) throws IOException,
ClassNotFoundException {
        ByteArrayInputStream bs= new ByteArrayInputStream(bytes); //
bytes es el byte[]
        ObjectInputStream is = new ObjectInputStream(bs);
        Dato objeto = (Dato)is.readObject();
        is.close();
        bs.close();

        return objeto;
    }

Can someone help with this?