I was wondering about the way the data are transferred between the layers of a n-tier architecture ? For example, in spring web mvc, under which format do they move from one layer to another ?
In a n-tier architecture, the format of the data is generally defined by the tier. If you are communicating between a database tier and a business logic tier, it will probably be JDBC. If it is between a business-logic tier and a web tier it will probably be either a service protocol (JSON, SOAP, etc), or a remoting protocol (RMI, etc). If it is between the client (web browser) and the web tier, it's probably HTML or JSON.