1b) Annotation your JAXB beans to enable MTOM

If you're doing code first, you need to add an annotation to your POJO to tell JAXB that the field is a candidate for MTOM optimization. Lets say we have a Picture class with has Title and ImageData fields, then it might look like this:

@XmlType
public class Picture {
   private String title;

   @XmlMimeType("application/octet-stream")
   private DataHandler imageData;

   public String getTitle() { return title; }
   public void setTitle(String title) { this.title = title; }

   public DataHandler getImageData() { return imageData; }
   public void setImageData(DataHandler imageData) 
      { this.imageData = imageData; }
}

Note the use of 'application/octet-stream'. According to the standard, you should be able to use any MIME type you like, in order to specify the actual content of the attachment. However, due to a defect in the JAX-B reference implementation, this won't work.