I want to start off by saying I do have information about each of these questions in a text book I was given but like most text books the examples they give are a lot easier to see how they are solved then actually solving the problems they give. But I gave each one a shot.
In question 1 I was supposed to figure out whether or not each action was legal.

1.
Suppose the class Sandwich implements the Edible interface, and you are given the variable definitions
Sandwich sub = new Sandwich();
Rectangle cerealBox = new Rectangle(5, 10, 20, 30);
Edible e = null;
Which of the following assignment statements are legal?
a. e = sub;
b. sub = e;
c. sub = (Sandwich) e;
d. sub = (Sandwich) cerealBox;
e. e = cerealBox;
f. e = (Edible) cerealBox;
g. e = (Rectangle) cerealBox;
h. e = (Rectangle) null

My answers are below with reasoning.

a. e = sub; is not legal because not everything that is edible is going to be a sub
b. sub = e; is legal because every sub is edible
c. sub = (Sandwich) e; is legal because each sub is going to be a sandwich which is edible
d. sub = (Sandwich) cerealBox; is not legal because a sub does not make a sandwich that is in class cerealBox
(From here on is where I started to get confused)
e. e = cerealBox; is not legal because cerealBox is not edible
f. e = (Edible) cerealBox; is legal because in this case cerealBox is edible
g. e = (Rectangle) cerealBox; is not legal becuase a rectangular cerealBox is not edible
h. e = (Rectangle) null; is legal because edible is whatever class null is going to be legal

Note: For my assignment I do not need the reasoning why one is legal or not but wanted to show that I at least attempted to use reasoning on why one was legal or not. Once again if you think my reasoning makes no sense it most likely won't the examples I was given didn't really give me any help so I'm trying to figure out exactly how this would work.

2.
Suppose r contains a reference to a new Rectangle(5, 10, 20, 30). Which of the following assignments is legal?
a. Rectangle a = r; legal because this is just stating that their is a rectangle called Rectangle a and it has the same coordinates as the new Rectangle
b. Shape b = r; legal because Rectangle is under the Shape hierarchy
c. String c = r; legal because the String would have the same values as Rectangle r
d. ActionListener d = r; I could not find anything about ActionListener but I'm guessing not legal?
e. Measurable e = r; not legal I'm pretty sure that measureable refers to text?
f. Serializable f = r; I was looking the the java.sun website and I think from what I saw that this would be legal
g. Object g = r; legal because Rectangle is under the hierarchy of class Object

3.
Classes such as Rectangle2D.Double, Ellipse2D.Double and Line2D.Double implement the Shape interface. The Shape interface has a method
Rectangle getBounds()
that returns a rectangle completely enclosing the shape. Consider the method call:
Shape s = . . .;
Rectangle r = s.getBounds();
Explain why this is an example of polymorphism.

I think this is an example of polymorphism because it allows the values of shape s, rectangle r. , and s.getBounds to be handled using a
single interface.

egjactly!!!