Why we should develop a multilayer application ?

One can ask why going into difficulties by multiplying the code layers. The answer might be quiet simple; it’s to make your life easier. We are at a time of great technological revolution where applications can no more live for themselves. Whether we face needs internal to a company or we are developing for a software editor we will need to share or to expose our code to other applications at one time or another. Our need can evolve in a great set of needs and future informations would have to be shared between layers of codes already written. If our application has been implemented as a monolithic block of code it could be very difficult to adapt it, and the only options would be to break the code that has been written so painfully or to write a brand new application. That’s why it is necessary to take good habits even if it can be a difficult process at the very beginning.