@Entity
@Table(name="FileEntity")
public class FileEntity {

   private Integer id;
   private String path;
   private String name;
   private Blob data;
   private long size;
   
   public long getSize() {
      return size;
   }

   public void setSize(long size) {
      this.size = size;
   }

   public FileEntity() {}
   
   @Id
   @GeneratedValue
   public Integer getId() {
      return id;
   }

   public void setId(Integer id) {
      this.id = id;
   }

   public String getPath() {
      return path;
   }

   public void setPath(String path) {
      this.path = path;
   }

   public String getName() {
      return name;
   }

   public void setName(String name) {
      this.name = name;
   }

   @Lob
   @Basic(fetch = FetchType.LAZY)
   public Blob getData() {
      return data;
   }

   public void setData(Blob data) {
      this.data = data;
   }

   @Transient
   public InputStream getDataStream() throws SQLException {
      if (getData() == null)
         return null;

      return getData().getBinaryStream();
   }

   @Transient
   public void setDataStream(InputStream sourceStream) throws IOException {
      setData(Hibernate.createBlob(sourceStream));
   }

}

   <target name="instrument">
       <taskdef name="instrument" classname="org.hibernate.tool.instrument.javassist.InstrumentTask">
           <classpath path="bin"/>
           <classpath refid="lib.class.path"/>
       </taskdef>

       <instrument verbose="true">
           <fileset dir="bin/com/solabs/test">
               <include name="FileEntity.class"/>
           </fileset>
       </instrument>
   </target>

--- MBEANS THAT ARE THE ROOT CAUSE OF THE PROBLEM ---
ObjectName: persistence.units:jar=Alibaba2Test.jar,unitName=alibabaDS
  State: FAILED
  Reason: javax.persistence.PersistenceException: org.hibernate.MappingException
: [b]Could not determine type for: org.hibernate.bytecode.javassist.FieldHandler, f
or columns: [org.hibernate.mapping.Column(fieldHandler)][/b]
  I Depend On:
    jboss.jca:service=DataSourceBinding,name=alibabaDS
  Depends On Me:
    jboss.j2ee:jar=Alibaba2Test.jar,name=Tester,service=EJB3