Azure service bus with Java

Data is transferred between different applications and services using messages. A message is a container decorated with metadata, and contains data. The data can be any kind of information, including structured data encoded with the common formats such as the following ones: JSON, XML, Apache Avro, Plain Text.

Some common messaging scenarios are:

• Messaging. Transfer business data, such as sales or purchase orders, journals, or inventory movements.

• Decouple applications. Improve reliability and scalability of applications and services. Producer and consumer don't have to be online or readily available at the same time. The load is leveled such that traffic spikes don't overtax a service.

• Load balancing. Allow for multiple competing consumers to read from a queue at the same time, each safely obtaining exclusive ownership to specific messages.

• Topics and subscriptions. Enable 1:n relationships between publishers and subscribers, allowing subscribers to select particular messages from a published message stream.

• Transactions. Allows you to do several operations, all in the scope of an atomic transaction. For example, the following operations can be done in the scope of a transaction.

  1. Obtain a message from one queue.

  2. Post results of processing to one or more different queues.

  3. Move the input message from the original queue.

  The results become visible to downstream consumers only upon success, including the successful settlement of input message, allowing for once-only processing semantics. This transaction model is a robust foundation for the compensating transactions pattern in the greater solution context.

• Message sessions. Implement high-scale coordination of workflows and multiplexed transfers that require strict message ordering or message deferral.

If you're familiar with other message brokers like Apache ActiveMQ, Service Bus concepts are similar to what you know. As Service Bus is a platform-as-a-service (PaaS) offering, a key difference is that you don't need to worry about the following actions. Azure takes care of those chores for you.

• Worrying about hardware failures

• Keeping the operating systems or the products patched

• Placing logs and managing disk space

• Handling backups

• Failing over to a reserve machine