Application server it sits between the network and the database, thenWhat does the application server actually do and what does it do?
The application server is the code that provides the business logic for the application. It is component-based and sits in the middle tier of a server-centric architecture.
This architecture is primarily Web-based. The middle tier is the application server where the business logic resides. The third layer, on the other hand, is the database of the transaction server. The application server acts as the interaction between the user and the database.
The application server exposes the business logic to the client's program through various protocols. It may also include a graphical user interface on a computer, web server, or other application server. The business logic is exposed through the component API. It also manages its own resources as well as enforcing security, transaction processing, resource pooling, and messaging. Related reading: what are the server application categories included?