What is Java Message Service (JMS) for?

Question

I am currently evaluating JMS and I don\'t get what I could use it for.

Currently, I believe this would be a Usecase: I want to create a SalesInvoice PDF and print it w

Answer 1

Messaging is usually used to interconnect different systems and send requests/commands asynchronously. A common example is a bank client application requesting an approval for a transaction. The server is located in another bank's system. Both systems are connected in an Enterprise Service Bus. The request goes into the messaging bus, which instantly acknowledges the reception of the message. The client can go on with processing. Whenever the server system becomes available, the bus forwards the message to it. Of course there needs to be a second path, for the server to inform the client that the transaction executed successfully or failed. This again can be implemented with JMS.

Please note that the two systems need not to implement JMS. One can use JMS and the other one MSMQ. The bus will take care of the interconnection.