Question

We are building an application that will have clients installed in many sites. Each client work on its own, has its own database and workflows. However, each client has to submit some data to the main application installed at a central position. The application at a central location must receive updates (e.g stock levels) from the distributed units. All applications are done in Java. Which is the best way/technology of sending the updates from the distributed units to the central application? JMS, jdbc, …?

Answer 1

I’m going to assume that the servers at client sites have network access, and that you are able to configure the central server so that other clients can connect to it. This could either be over the internet or an internal WAN.

In this case, it’s simply a case of finding a mechanism to submit some correctly formatted data, which is received and handled by the central server. This gives you a large number of options, I’m going to list just a few:

• Create a web service with something like Apache Axis
• Use an ESB – something like Mule or JBoss
• Use a simple web Servlet on the server, and submit data using HTTP POST. You could use a simple embeddable Java web server like Jetty to do this.
• Use a messaging protocol like Kryonet or Google’s protocol buffers
• Use a more general network application framework such as Netty

All of these will work, so it really depends on working out which is the best fit for your architecture. I suspect the simplest would be something like Kryonet, the most comprehensive would probably be something like a full JBoss ESB/application server stack.