Improving structure with inheritance - Objects First with Java: A Practical Introduction Using BlueJ - page 301

Exercise 8.16 Go back to the lab-classes project from Chapter 1. Add instructors to the pro-
ject (every lab class can have many students and a single instructor). Use inheritance to avoid
code duplication between students and instructors (both have a name, contact details, etc.).
Exercise 8.17 Draw an inheritance hierarchy representing parts of a computer system
(processor, memory, disk drive, DVD drive, printer, scanner, keyboard, mouse, etc.).
Exercise 8.18 Look at the code below. You have four classes ( O , X , T , and M ) and a variable
of each of these.
O o;
X x;
T t;
M m;
The following assignments are all legal (assume that they all compile):
m = t;
m = x;
o = t;
The following assignments are all illegal (they cause compiler errors):
o = m;
o = x;
x = o;
What can you say about the relationships of these classes? Draw a class diagram.
Exercise 8.19 Draw an inheritance hierarchy of AbstractList and all its (direct and
indirect) subclasses as they are defined in the Java standard library.