Hi -

I use Hibernate 2.1.2, Tomcat 4.1.29, mysql 4 and mapped a
blob to byte[] as descibed in http://www.hibernate.org/73.html using a UserType.
In my application I have 2 blob columns in the database. I read the first column (a thumbnail), convert it and try to write it back to the second column.
However, I get an exception in method nullSafeSet of the UserType when
the session is flushed:
net.sf.hibernate.lob.BlobImpl.excep(BlobImpl.java:95)
at net.sf.hibernate.lob.BlobImpl.getBytes(BlobImpl.java:48)
at com.mysql.jdbc.PreparedStatement.setBlob(PreparedStatement.java:358)
at org.apache.commons.dbcp.DelegatingPreparedStatement.setBlob(DelegatingPreparedStatement.java:260)
at MyBinaryBlob.nullSafeSet(BinaryBlob.java:57)


For nullSafeSet I tried

public void nullSafeSet(PreparedStatement st, Object value, int index)
throws HibernateException, SQLException
{
if (value!=null) {
Blob b=new BlobImpl((byte[])value);
st.setBlob(index, b);
}
}


and alternatively
st.setBlob(index, Hibernate.createBlob((byte[]) value));

isMutable() returns true.

Thank you for any solution hint -
Christian

sorry, I forgot the message of the exception:

java.lang.UnsupportedOperationException: Blob may not be manipulated from creating session

Hello! I am running into this exact problem. Do you recall how you solved it? Many thanks!!

FYI to any who might happen to stumble upon this thread in the future: I fixed the problem by changing setBlob to setBytes, and everything now works!