How to put blob ( > 4k )  into Oracle9 using Hiberanete?

I got problem with inserting BLOB > 4k into Oracle database.

Example from http://www.hibernate.org/56.html do not works.

I use Tomcata5.5, Hibernate2.1.7, Oracle9, Java 1.5.

This line in my code:
( (oracle.sql.BLOB)atta.getData() ).putBytes(0,temp);

throws ClassCastException , why??

Is any other way to insert Blob into Oracle?

Do I have to use some other driver then oracle.thin ?
My context.xml looks like:

<Resource
    name="jdbc/test"
    auth="Container"
    type="javax.sql.DataSource"
    username="migration"
    password="***"
    driverClassName="oracle.jdbc.driver.OracleDriver"
    url="jdbc:oracle:thin:@123.123.123.123:2222:TEST"
    maxActive="100"
    maxIdle="10"
    maxWait="3000"
  />

Code is:

     session = HibetnateUtil.currentSession();
     tx = sessison.beginTransaction();
...
     atta.setData( Hibernate.createBlob("temporary".getBytes()) );
     session.save(atta);
     session.flush();
     byte[] temp = atta.getBytes();
     session.refresh( atta, LockMode.UPGRADE );
     ( (oracle.sql.BLOB)atta.getData() ).putBytes(0,temp);
     tx.commit();
     session.flush();