Ans)

A BLOB (Binary Large OBject) is essentially an array of bytes (byte[]), stored in the database. You extract the data in two steps:

    Call the getBlob method of the PreparedStatement class to retrieve a java.sql.Blob object
    Call either getBinaryStream or getBytes in the extracted Blob object to retrieve the java byte[] which is the Blob object.
 
         PreparedStatement stmnt = conn.prepareStatement("select aBlob from BlobTable");
         // Execute
         ResultSet rs = stmnt.executeQuery();
         while(rs.next())
         {
            try
            {
               // Get as a BLOB
               Blob aBlob = rs.getBlob(1);
               byte[] allBytesInBlob = aBlob.getBytes(1, (int) aBlob.length());
            }
            catch(Exception ex)
            {
            }
         }
       rs.close();
       stmnt.close();

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