Re: JAVA_OBJECT Problem with byte[64] and byte[0] array

Thanks.  I wrote a test case for this and was able to reproduce the error.

This is actually a design flaw in the way the Mckoi JDBC driver sends 
and receives Java byte[] objects.  When serializing a Java object, Mckoi 
wraps the serialized data form in a ByteLongObject (which is basically 
just a byte[] array).  Unfortunately, Mckoi also uses a ByteLongObject 
to represent byte[] objects.  When using 'getObject', Mckoi 
automatically assumes the ByteLongObject is a serialized Java object and 
attempts to deserialize it.  When it's a byte[] array, this fails.

An easy workaround for you would be to wrap all byte[] objects that you 
give to 'setObject' with a custom Serializable class.  eg.

class AByteArray implements java.io.Serializable {
   byte[] byte_arr;
}

So all byte[] objects read with 'getObject' would become AByteArray 
objects instead.

Unfortunately this kind of fix can't be implemented in the JDBC driver 
code because getObject has to work for byte[] array data that has been 
written to the database in other ways.

Hope this helps and thanks for the bug report,
Toby.


Klaus, Gerd wrote:

> Sorry, I forgot the Mckoi Version. I am using Mckoi 1.0.3.
> 
> Best Regards,
> Gerd 
> 
> 
>>-----Original Message-----
>>From: [email protected] [mailto:[email protected]] On Behalf 
>>Of Klaus, Gerd
>>Sent: Thursday, February 09, 2006 3:09 PM
>>To: [email protected]
>>Subject: JAVA_OBJECT Problem with byte[64] and byte[0] array
>>
>>Hi All,
>>
>>Table definition:
>>
>>CREATE TABLE IF NOT EXISTS xyz (
>>    identifier  INTEGER NOT NULL PRIMARY KEY,
>>    parameter   JAVA_OBJECT);
>>
>>Data in Table:
>> identifier | parameter
>> -----------+-------------
>>     1      | boolean[64]
>>     2      | byte[64]
>>     3      | int[64]
>>     4      | int[64]
>>     5      | boolean[64]
>>     6      | int[1]
>>     7      | byte[0][0]
>>     8      | byte[0]
>>     9      | int[0]
>>    10      | int[0]
>>    11      | boolean[0]
>>    12      | boolean[1]
>>    13      | boolean[1]
>>
>>INSERT and UPDATE works fine with all 13 identifier.
>>
>>READING data with "SELECT identifier,parameter FROM xyz ORDER BY
>>identifier ASC;" also. But if I try to read the 'parameter' 
>>column with
>>"ResultSet.getObject(2)" after a the SELECT, an exception at
>>'identifier' 2 and 8 is thrown:
>>
>>Exception at identifier 2:
>>Exception in thread "main" java.lang.Error: De-serialization error:
>>invalid stream header
>>   at
>>com.mckoi.database.global.ObjectTranslator.deserialize(ObjectT
>>ranslator.
>>java:107)
>>   at
>>com.mckoi.database.jdbc.MResultSet.getRawColumn(MResultSet.java:592)
>>   at 
>>com.mckoi.database.jdbc.MResultSet.getObject(MResultSet.java:1105)
>>   at
>>mmr.DB.statements.DbAlarmBrdSer.getParameters(DbAlarmBrdSer.java:97)
>>   at mmr.MIDAS.loadAlarmBrdDat(MIDAS.java:1052)
>>   at mmr.MIDAS.main(MIDAS.java:692)
>>        
>>Exception at identifier 8:
>>Exception in thread "main" java.lang.Error: De-serialization 
>>error: null
>>   at
>>com.mckoi.database.global.ObjectTranslator.deserialize(ObjectT
>>ranslator.
>>java:107)
>>   at
>>com.mckoi.database.jdbc.MResultSet.getRawColumn(MResultSet.java:592)
>>   at 
>>com.mckoi.database.jdbc.MResultSet.getObject(MResultSet.java:1105)
>>   at
>>mmr.DB.statements.DbAlarmBrdSer.getParameters(DbAlarmBrdSer.java:102)
>>   at mmr.MIDAS.loadAlarmBrdDat(MIDAS.java:1052)
>>   at mmr.MIDAS.main(MIDAS.java:692)
>>
>>Any ideas why the exceptions are thrown?
>>
>>
>>Best regards,
>>
>>Gerd
> 
> 
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