Start of Headstrong Boot Camp

I'm here at the Headstrong office, it's the second day of their boot camp. We've started conducting our completely-overhauled Java Fundamentals curriculum, where we soak them for two whole days in OOP and OOD. I just gave a quiz this morning so I'll find out if they really got the concepts. Here are some of the questions I asked:

1. (1 pt) What is the worst sin in object-oriented programming?

duplicate code

2. (1 pt) If you are experiencing “shotgun surgery”, what should you do?

• consolidate related code together
• eliminate duplicate code

3. (1 pt) If you see data clumps or are having long parameter lists, what should you do?

• consolidate the data clumps into a classes

4. (2 pts) What are the five recommended guidelines in writing a good OO program?

• The Once and Only Once Rule
• The One Responsibility Rule
• The OO Prime Directive
• The Law of Demeter
• Well-Defined Interfaces, Hidden Implementations

5. (2 pts) State the “OO Prime Directive”. Any of the three versions given will suffice.
• Never ask an object for information that you need to do something; rather, ask the object that has the information to do the work for you.”
• Ask for help, not information.
• The maintainability of a program is inversely proportional to the amount of data that flows between objects.

6. (2 pts)State the Law of Demeter in its precise form. Complete the blanks below
A method of an object should only invoke the following kinds of objects:
1. itself
2. its parameters
3. any objects it instantiates
4. its direct component objects
7. (1 pt) State the Law of Demeter in its short form:

Don’t talk to strangers .

8. (3 pts) What are the three Core Principles of OOP? Define each.
• Encapsulation
o Bundling of related data and operations
o Information hiding
• Inheritance
o Creating a class by deriving attributes and methods from another class.
• Polymorphism
o When a single data type exhibits multiple behaviors during execution.
o Dynamic binding of a data type.
o “substitutability”
o “pluggability”

9. (1 pt) In a purely Object-Oriented Language, a class is what does the work. (TRUE / FALSE)

FALSE – An object/instance does the work. A class is just a specification/design/template.