Facade pattern is very common in object-oriented programming has been used widely. Façade name itself is through analogy is an architectural facade. By definition facade pattern is object which provides simplified interface client to larger body of programing for example java API class library. Below are some points which façade can do:
Because of common task and convenient method it makes software library easy to use, understand and perform test.
It also makes class library more readable with same explanation.
It reduces dependencies between outside coding and inner workings of library because if most code uses facade pattern means it allows more flexibility to developing the system.
It wraps up poorly designed collection of APIs with single good designed API according to need of the tasks.
Below is example will show you implementation of façade pattern using ordering pizza? Whenever you go to pizza restaurant there you call waiter give your choice of pizza order and wait for it. Basically here waiter is acting as facade which takes your order and use helper class to prepare pizza and finally deliver your order and you are unaware of process of making pizza.