Hibernate version:
2.1.6

Mapping documents:
<class
name="com.xxx.bean.Email"
table="EMAILS"
dynamic-update="true"
dynamic-insert="true"
>
<id
name="emailId"
type="long"
column="EMAIL_ID"
length="22"
>
<generator class="native"/>
</id>

<property
name="emailattachment"
type="java.lang.Object"
update="false" insert="false" >
<column name="EMAIL_ID" />
<column name="EMAILATTACHMENT"/>
</property>

Code between sessionFactory.openSession() and session.close():
InputStream is = new FileInputStream((File)email.getEmailattachment());
byte[] data = new byte[is.available()];
is.read(data);
is.close();

email.setEmailattachment((Object)Hibernate.createBlob(byte[1]));
getHibernateTemplate().save(o);
getHibernateTemplate().flush();
getHibernateTemplate().refresh(o, LockMode.UPGRADE);
writeBlob(data,(Blob)email.getEmailattachment());

protected final void writeBlob(byte[] data, Blob l_blob) throws Exception {
OutputStream out = ((oracle.sql.BLOB) l_blob).getBinaryOutputStream();
out.write(data);
out.close();
}


Full stack trace of any exception that occurs:
java.lang.RuntimeException: java.lang.RuntimeException: org.springframework.orm.hibernate.HibernateSystemException: No persister for: net.sf.hibernate.lob.BlobImpl; nested exception is net.sf.hibernate.MappingException: No persister for: net.sf.hibernate.lob.BlobImpl
Name and version of the database you are using:
Oracle 9

Debug level Hibernate log excerpt:

Post the code for Email class

Below is the code for email class:

public class Email implements Serializable {

/** identifier field */
private long emailId;

/** identifier field */
private Object emailattachment;

/** full constructor */
public Email(long emailId Object emailattachment) {
this.emailId = emailId;
this.emailattachment = emailattachment;
}

/** default constructor */
public Email() {
}

public long getEmailId() {
return this.emailId;
}

public void setEmailId(long emailId) {
this.emailId = emailId;
}

public Object getEmailattachment() {
return this.emailattachment;
}

public void setEmailattachment(Object emailattachment) {
this.emailattachment = emailattachment;
}


public String toString() {
return new ToStringBuilder(this)
.append("emailId", getEmailId())
.append("emailattachment", getEmailattachment())
.toString();
}

public boolean equals(Object other) {
if ( (this == other ) ) return true;
if ( !(other instanceof Email) ) return false;
Email castOther = (Email) other;
return new EqualsBuilder()
.append(this.getEmailId(), castOther.getEmailId())
.append(this.getEmailattachment(), castOther.getEmailattachment())
.isEquals();
}

public int hashCode() {
return new HashCodeBuilder()
.append(getEmailId())
.append(getEmailattachment())
.toHashCode();
}

}

can you declare "java.sql.Blob" or blob instead of object.

I know it works when I declare it as java.sql.Blob but I want to declare it as an Object and cast it as a Blob or File as per the requirements..

Is this possible or am trying to be insane?

If column is of type BLOB on the database side ( assuming Oracle database), I believe hibernate blob type would get picked up and used for transaction. I think thats why hibernate its using default imp of blob that comes with it.

yes, it is defined as a Blob in the database but as an Object in the mapping files and the persistence class.
so, why am I getting this error? Is it looking for a Blob?

i am no expert .. this is my theory and correct me if i am wrong..

even if its declared as Object, it needs some type of behaviour or characteristics. And when you declare as object, the default mapping to column type BLOB is BlobImpl ( in hibernate).

Do some system out and find whats the instance class behind it.