Explain the structure of a JMS message.
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Explain the structure of a JMS message.
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A JMS message has three parts – A header, properties and a body.
- A JMS message header contains a number of predefined fields like JMSDestination, JMSMessageID, JMSPriority etc. that contain values used by both clients and providers to identify and route messages.
- Message properties can be used if we want to send values in addition to those provided by header fields.
- The JMS API defines five message body types which helps in sending and receiving data in different forms:
- TextMessage – Message body contains a text message an object of java.lang.String.
- MapMessage – Message body contains a set of name-value pairs, with names as String objects and values as primitive types.
- BytesMessage – Message body contains a stream of uninterpreted bytes which is used for literally encoding a body to match an existing message format.
- StreamMessage – Message body contains a stream of primitive values, filled and read sequentially.
- ObjectMessage – Message body contains a Serializable Java object.
- Message – Message body contains nothing. This is composed of header fields and properties only. This message type is useful when a message body is not required.
