Problem 4 In Java/Swing, class JList is used to display the contents of a list. A JList is (only) responsible for displaying the contents of a list. The actual values in the list are supposed to be retrieved from a class that implements interface ListModel. JList is said to be a listener of the ListModel (i.e., it registers to ListModel), and is informed when the contents or the length of the list changes. Which architectural style is used here? Justify your answer and produce a UML object diagram representing the system using the given object names. NOTE: You can find information about UML object diagrams here: https://www. uml-diagrams. org/object.html