IBM MQ Java read msg Format incorrect

I want to read data from queue of MQ.
When I browse queue in MQExplorer I find messages with Format=MQSTR.

But when I read them, Format is MQHRF2 !!
My MQ server is MQ7.5 and use com.ibm.mq.allclient maven library.

MQMessage getMessage = new MQMessage();
getMessage.clearMessage();
MQGetMessageOptions mqGetMessageOptions = new MQGetMessageOptions();
queue.get(getMessage, mqGetMessageOptions);
String format = getMessage.format.trim();

I tried my source on other server and queue and works well (get MQSTR).

You need to understand the big picture then the coding will make sense.

A JMS message is actually an MQRFH2 message to IBM MQ internally. So, IBM allows the client application to receive the JMS message in 1 of 2 formats. i.e. JMS message or MQRFH2 message.

• A JMS message means that the message MQMD.Format will be 'MQSTR' and it will have Named Properties (aka Message Properties).
• An MQRFH2 message means that the message MQMD.Format will be 'MQHRF2' and it will have an embedded MQHRF2 structure that will contain the Named Properties (aka Message Properties).

Therefore, if you want the client application to receive a JMS message then you can code the following:

MQGetMessageOptions gmo = new MQGetMessageOptions();
gmo.options = CMQC.MQGMO_PROPERTIES_IN_HANDLE + CMQC.MQGMO_FAIL_IF_QUIESCING;
MQMessage getMsg = new MQMessage();
inQ.get(getMsg, gmo);

On the other hand, if you want the client application to receive an MQRFH2 message then you can code the following:

MQGetMessageOptions gmo = new MQGetMessageOptions();
gmo.options = CMQC.MQGMO_PROPERTIES_FORCE_MQRFH2 + CMQC.MQGMO_FAIL_IF_QUIESCING;
MQMessage getMsg = new MQMessage();
inQ.get(getMsg, gmo);

If you go with the MQRFH2 message, you can still get access to the Named Properties in the message's payload by using the MQRFH class. Note: User/application properties are stored in the 'usr' folder.

MQRFH2 rfh2 = new MQRFH2(getMsg);
String value = rfh2.getStringFieldValue ("usr", "MyProp");

Finally, for MQ APIs calls like MQOPEN, MQGET, MQPUT or MQPUT1, it is MQ Best Practises to use/code the 'Fail if Quiescing' option.

i.e.

int openOptions  = CMQC.MQOO_INPUT_AS_Q_DEF + CMQC.MQOO_FAIL_IF_QUIESCING;
MQQueue inQ = qMgr.accessQueue(inputQName, openOptions);
MQGetMessageOptions gmo = new MQGetMessageOptions();
gmo.options = CMQC.MQGMO_PROPERTIES_IN_HANDLE + CMQC.MQGMO_FAIL_IF_QUIESCING;
MQMessage getMsg = new MQMessage();
inQ.get(getMsg, gmo);

And:

int openOptions = CMQC.MQOO_OUTPUT + CMQC.MQOO_FAIL_IF_QUIESCING;
MQQueue outQ = qMgr.accessQueue(outputQName, openOptions);
MQPutMessageOptions pmo = new MQPutMessageOptions();
pmo.options = CMQC.MQPMO_FAIL_IF_QUIESCING;
MQMessage putMsg = new MQMessage();
putMsg.writeString("This is a test message.");
outQ.put(putMsg, pmo);