SCJP Practice Question

Question

I'm working through the McGraw Hill SCJP study guide for Java 5, and I don't much care for the following question:
(page 159)
5. Select the two statements that best indicate a situation whit low coupling. (Choose two.)
A. The attributes of the class are all private.
B. The class refers to a small number of other objects.
C. The object contains only a small number of variables.
D. The object is referred to using an anonymous variable, not directly.
E. The reference variable is declared for an interface type, not a class. The interface provides a small number of methods.
F. It is unlikely that changes made to one class will require any changes in another.
Answer:
E and F are correct. Only having access to a small number of methods implies limited coupling. If the access is via a reference of interface type, it may be argued that there is even less opportunity for coupling as the class type itself is not visible. Stating that changes in one part of a program are unlikely to cause consequences in another part is really the essence of low coupling. There is no such thing as an anonymous variable. Referring to only a small number of other objects might imply low coupling, but if each object has many methods, and all are used, then coupling is high. Variables (attributes) in a class should usually be private, but this describes encapsulation, rather than low coupling. Of course, good encapsulation tends to reduce coupling as a consequence.
I would have thought A and E were the answers here. If the attributes of a class are all private, you're going to have to use accessors and mutators to get to them, which is a prime example of loosely coupled code. I disagree that "F. It is unlikely that changes made to one class will require any changes in another." is a proper answer because although it does cut right to the heart of the matter, it does not describe the mechanism through which this feat has been accomplished and leads me to believe that perhaps the class has been designed with likely future changes in mind such that they will have a low impact but other unforseen changes may cause problems.
Am I out of line here?
If so, please enlighten me!
If not, ... yarrrgh! If there are questions like this on the exam, I expect to have problems with them. Any suggestions? How can I get my reasoning to line up with the test, at least for the day of the exam? ;)
Thank you in advance for any assistance!

Answer 1

I think you're making a general mistake you have to come to terms with before you attempt the exam. You're reading stuff into the statements that aren't there. You must learn to consider the statements just as they stand and don't modify them in your mind.
For example,
If the attributes of a class are all
private, you're going to have to use accessors and
mutators to get to them,That's not what the statement says. It says all attributes are private, nothing else.
it does cut right to the heart of the
matter, it does not describe the mechanism through
which this feat has been accomplishedWho said mechanisms must be provided? The statement cuts right to the heart of the matter as it stands.