Problem enqueuing with SYS.AQ$_JMS_TEXT_MESSAGE payload

Question

We are trying to enqueue a message into a SYS.AQ$_JMS_TEXT_MESSAGE AQ from java using the standard AQjmsQueueSender. The message arrives onto the queue but the USER_DATA is always 'oracle.sql.STRUCT@5a41ec' instead of the actual message. When we enqueue from PL/SQL the USER_DATA contains the actual message. Any help would be greatly appreciated. Thanks.
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi
PL/SQL Release 10.2.0.4.0 - Production
"CORE     10.2.0.4.0     Production"
TNS for Linux: Version 10.2.0.4.0 - Production
NLSRTL Version 10.2.0.4.0 - Production
QUEUE DETAILS
OWNER:     EIMGR
QUEUE_TABLE:     AQ_VENDORS_IN_TABLE
TYPE: OBJECT
OBJECT_TYPE:     SYS.AQ$_JMS_TEXT_MESSAGE
SORT_ORDER:     ENQUEUE_TIME
RECIPIENTS:     SINGLE
MESSAGE_GROUPING:     NONE
COMPATIBLE: 8.1.3
PRIMARY_INSTANCE: 0
SECONDARY_INSTANCE:     0
OWNER_INSTANCE:     1
USER_COMMENT: EI_QUEUE
SECURE:     NO
CREATED:     09-09-03
LAST_DDL_TIME: 09-09-03
-------------------------------------------------------------------------------------

Answer 1

We've discovered with PL/SQL that setting any headers on messages causes the same problem that we're seeing from JAVA. There is no option in JAVA to send messages without headers (it's part of the JMS spec). This can be seen with the following PL/SQL script (use null instead of HEADER in the message constructor to see it work):
DECLARE
Enqueue_options DBMS_AQ.enqueue_options_t;
Message_properties DBMS_AQ.message_properties_t;
Message_handle RAW(16);
User_prop_array SYS.AQ$_JMS_USERPROPARRAY;
Agent SYS.AQ$_AGENT;
Header SYS.AQ$_JMS_HEADER;
Message SYS.AQ$_JMS_TEXT_MESSAGE;
Message_text VARCHAR2(500);
BEGIN
Agent := SYS.AQ$_AGENT('',NULL,0);
User_prop_array := SYS.AQ$_JMS_USERPROPARRAY();
Header := SYS.AQ$_JMS_HEADER( Agent, '', 'dave', '', '', '', User_prop_array);
Message_text := 'Message from PL/SQL created at '|| TO_CHAR(SYSDATE, 'mm/dd/yyyy hh24:mi:ss');
Message := SYS.AQ$_JMS_TEXT_MESSAGE(Header, LENGTH(Message_text), Message_text, NULL);
DBMS_AQ.ENQUEUE(queue_name => 'AQ_VENDORS_IN',
Enqueue_options => enqueue_options,
Message_properties => message_properties,
Payload => message,
Msgid => message_handle);
COMMIT;
END;