This class worked for me however I was facing a class cast exception 
when I used the nullSafeSet method with

st.setClob(index, Hibernate.createClob((String) value));

I had to modify it to the following

 public void nullSafeSet(PreparedStatement st, Object value, int index)
	        throws HibernateException, SQLException
	    {
	    	if (value != null) {
	             StringReader((String)value );
		  st.setString(index, (String)value);	
	    } else {

		  st.setNull(index, sqlTypes()[0]);
	    }

	    }

It works for me now