PRO192_part6

22. Suppose you are writing a class that will provide custom deserialization. The class implements java.io.Serializable (not java.io.Externalizable). What access mode should the readObject() method have?

• A. public

• B. protected

• C. default

• D. private

31. Suppose threads aThread and bThread are both accessing a shared object named sharedOb, and aThread has just executed:
sharedOb.wait();

What code can bThread execute in order to get aThread out of the waiting state, no matter what other conditions prevail?

• A. aThread.notify();

• B. aThread.notifyAll();

• C. aThread.interrupt();

• D. sharedOb.notify();

• E. sharedOb.notifyAll();

39. What relationship does the extends keyword represent?

• A. "is a"

• B. "has a"

• C. Polymorphism

• D. Multivariance

• E. Overloading

38. Given the following code:
1. class Xyz {
2. float f;
3. Xyz() {
4. ??? // What goes here?
5. }
6. Xyz(float f) {
7. this.f = f;
8. }
9. }

What code at line 4 results in a class that compiles?

• A. super();

• B. this(1.23f);

• C. this(1.23f); super();

• D. super(1.23f); this(1.23f);

37. What happens when you try to compile the following code and run the Zebra application?
class Animal { float weight; Animal(float weight) {
this.weight = weight;
}
}

class Zebra extends Animal {
public static void main(String[] args) { Animal a = new Animal(222.2f);
Zebra z = new Zebra();
}
}

• A. Class Animal generates a compiler error.

• B. Class Zebra generates a compiler error.

• C. The code compiles without error. The application throws an exception when the Animal
  constructor is called.

• D. The code compiles without error. The application throws an exception when the Zebra
  constructor is called.

• E. The code compiles and runs without error.

36. Suppose class aaa.Aaa has a method called callMe(). Suppose class bbb.Bbb, which extends aaa.AAA, wants to override callMe(). Which access modes for callMe() in aaa.AAA will allow this?

• A. public

• B. protected

• C. default

• D. private

35. Suppose classes Lemon and Grapefruit extend class Citrus. Which statements are true regard- ing the following code?
1. Grapefruit g = new Grapefruit();
2. Citrus c = (Citrus)g;
3. Lemon lem = (Lemon)c;

• A. The cast in line 2 is not necessary.

• B. Line 3 causes a compiler error.

• C. The code compiles, and throws an exception at line 3.

• D. The code compiles and runs without throwing any exceptions.

34. Suppose class Lemon extends class Citrus. Given the following code:
Lemon lem = new Lemon(); Citrus cit = new Citrus();
Which lines compile without error? (Choose all that apply.)

• A. lem = cit;

• B. cit = lem;

• C. lem = (Lemon)cit;

• D. cit = (Citrus)lem;

• E. cit = (Object)lem;

33. Suppose class Home has methods chopWood() and carryWater(); it also has a method called chopWoodAndCarryWater(), which just calls the other two methods. Which statements are true? (Choose all that apply.)

• A. chopWoodAndCarryWater() is an example of appropriate cohesion.

• B. chopWoodAndCarryWater() is an example of inappropriate cohesion.

• C. chopWoodAndCarryWater() is an example of appropriate coupling.

• D. chopWoodAndCarryWater() is an example of inappropriate coupling.

32. Suppose class Car has public variables forceOnGasPedal and forceOnBrakePedal, and a public method respondToPedalChanges(). Class Driver manipulates an instance of Car by changing the variables and then calling the method. Which statements are true? (Choose all that apply.)

• A. The Car and Driver classes are loosely coupled.

• B. The Car and Driver classes are tightly coupled.

• C. This degree of coupling is desirable.

• D. This degree of coupling is undesirable.