The ESB can be used as the intermediary integration layer between two or more disparate systems and services. The ESB can be placed between the JSON-based mobile application and the SOAP-based web service. Without writing any code, you can configure the ESB to do the message format conversion. If the business use case needs to be extended further to include another service, you can integrate that service to the ESB, and rather than having point-to-point links, all three systems can be connected through the unified ESB integration layer.
You can imagine with out ESB, any application need an point-to-point integration and it will become out-of-control if number of applications is huge.
But with ESB any connections of any method is centralized at ESB.
ESB can be used in government system or any complicated system that number of applications need to connected is large and you want to make an centralization to deal with kind of massive connection. This make life for easier.
