The context is a mechanism for the interchange of data between the components of the windows and the services.
The context stores to objects (data) associate to a name.
The context is shared by all the objects of a window. If from a window we go to another one, is created a new context son, who contains all the data of the previous window but he cannot modify them. If we modified a data, the change is local, and when we return to the previous window, that modification appears. If on the contrary, we go to a new window, the local information propagates to the new window.
Also we can define "listeners", that is to say, objects that are waiting for the changes of variable determining.

The context is used of automatic form, without having to do it explicitamente.
What we do is, for example, to define that a "Label" shows the value of a variable of the context (then the label remains listening to the possible changes of value). On the other hand, we defined a "text field" because its value keeps with a certain name. If we changed the value of that field, and the name that we give him is the same one that we gave the label, this one changes automatically of value.
This way we defined the interaction between the components of the windows without programming in Java, and knowing the complexities the system of Events of Swing.