1a) Disagree. The constructor for X should be used to initialize the fields
    of X.
    
1b) X objects are created as subobjects of Y and Z objects (i.e., every
    Y and Z object has an X object inside of it).
    
1c) Any weaker precondition is acceptable; e.g., aIn > -1

1d) Any stronger precondition is acceptable; e.g., returns aIn + 1


2a) An alias of t is just another name for t:

    List<Date> alias = t;

    0 ArrayList objects will be created
    0 Date objects will be created
    
2b) A shallow copy of t makes a new list, but does not make new elements of
    the list:

    List<Date> shallow = new ArrayList<Date>(t);
    
    1 ArrayList objects will be created
    0 Date objects will be created
    
2c) A deep copy of t makes a new list, and makes new elements for the new
    the list:

    List<Date> shallow = new ArrayList<Date>(t);
    
    1 ArrayList objects will be created
    2 Date objects will be created
    
2d) A shallow copy.

2e) You must make a new HashMap<String, Date>
    For each key (keys are String references), you must make a deep copy
    of the corresponding value (values are Date references). You do not
    need to create new keys because String is immutable.
    

3a) The Controller must invoke View methods.

3b) The Controller must invoke Model methods.

3c) The View creates the JButton.

3d) The JButton has a reference to the Controller because the JButton must
    invoke the ActionPerformed method in the Controller.