OS : Win xp
Seam 1.2.1 GA @ JBOSS 4.2.2 GA
I tried both
private InputStream picturedata;
or
private byte[] picturedata;[]

i am getting following error

23:09:06,203 WARN [lifecycle] javax.el.ELException: /private/profile/profile.xhtml @43,5 data="#{privatePerson.picturedata}": Error writing 'picturedata' on type org.javassist.tmp.java.lang.Object_$$_javassist_15
javax.faces.el.EvaluationException: javax.el.ELException: /private/profile/profile.xhtml @43,5 data="#{privatePerson.picturedata}": Error writing 'picturedata' on type org.javassist.tmp.java.lang.Object_$$_javassist_15
 at javax.faces.component.ValueBindingValueExpressionAdapter.setValue(ValueBindingValueExpressionAdapter.java:147)
 at org.jboss.seam.ui.UIFileUpload.decode(UIFileUpload.java:57)

I am using this interface and implemented all methods.

public interface PrivatePersonService {
 public String updatePerson();
 public InputStream getPicturedata();
 public void setPicturedata(InputStream data) ;
 public String getContentType() ;
 public void setContentType(String contentType);
 public String getFileName();
 public void setFileName(String fileName);
 public String getTitle() ;
 public void setTitle(String title);
}

@Stateless
@Name("privatePerson")
public class PrivatePerson implements PrivatePersonService {
 @In
 @Out
 User user;
 @In
 EntityManager entityManager;
 @In
 FacesMessages facesMessages;
 @In
 FacesContext facesContext;
 @Logger
 Log log;
 private String contentType;
 private String fileName;
 private String title;
 private InputStream picturedata;
 public String updatePerson() {
 try {
 entityManager.merge(user.getPerson());
 if (getPicturedata() != null) {
 //....
 }

 } catch (Exception e) {

 }
 return "";
 }

 /**
 * @return the data
 */
 public InputStream getPicturedata() {
 return picturedata;
 }

 /**
 * @param data
 * the data to set
 */
 public void setPicturedata(InputStream picturedata) {
 this.picturedata = picturedata;
 }

 /**
 * @return the contentType
 */
 public String getContentType() {
 return contentType;
 }

 /**
 * @param contentType
 * the contentType to set
 */
 public void setContentType(String contentType) {
 this.contentType = contentType;
 }

 /**
 * @return the fileName
 */
 public String getFileName() {
 return fileName;
 }

 /**
 * @param fileName
 * the fileName to set
 */
 public void setFileName(String fileName) {
 this.fileName = fileName;
 }

 /**
 * @return the title
 */
 public String getTitle() {
 return title;
 }

 /**
 * @param title
 * the title to set
 */
 public void setTitle(String title) {
 this.title = title;
 }

}

i configured web.xml

<filter>
 <filter-name>Seam Filter</filter-name>
 <filter-class>org.jboss.seam.web.SeamFilter</filter-class>
 </filter>
 <filter-mapping>
 <filter-name>Seam Filter</filter-name>
 <url-pattern>/*</url-pattern>
 </filter-mapping>

component.xml file

<component class="org.jboss.seam.web.MultipartFilter">
 <property name="createTempFiles">true</property>
 <property name="maxRequestSize">1000000</property>
 </component>

Server log show multipart component is intalled.