java get object size

class Memory {

  /**
   * Function that get the size of an object.
   * 
   * @param object
   * @return Size in bytes of the object or -1 if the object
   * is null.
   * @throws IOException
   */
  public static final int sizeOf(Object object) throws IOException {
    
    if (object == null)
      return -1;
    
    // Special output stream use to write the content
    // of an output stream to an internal byte array.
    ByteArrayOutputStream byteArrayOutputStream =
      new ByteArrayOutputStream();
    
    // Output stream that can write object
    ObjectOutputStream objectOutputStream =
      new ObjectOutputStream(byteArrayOutputStream);
    
    // Write object and close the output stream
    objectOutputStream.writeObject(object);
    objectOutputStream.flush();
    objectOutputStream.close();
    
    // Get the byte array
    byte[] byteArray = byteArrayOutputStream.toByteArray();
    
    // TODO can the toByteArray() method return a
    // null array ?
    return byteArray == null ? 0 : byteArray.length;
    
    
  }

}