Answer Happy

Question 12 Consider the following Java code. Integer x = calculateValue(); if (x) { System.out.println("correct"); } int y = x + 3; Which of the following statements are true? Select all that apply. This code uses the principle of unboxing. □ If x is not zero, the message correct will be printed. If x is null, the message correct will not be printed. This code will cause a runtime error. This code will cause a compilation error. Question 13 2 pts Which of the following statements regarding event driven programming are correct? You may select more than one answer. An event is usually generated due to a state change. A listener can handle events only from one component. Multiple listeners can respond to the same event. Event driven design results in better encapsulation. Event driven design decreases coupling between components. 2 pts

Question 16 Which of the following statements about encapsulation are true? Select all that apply. If all instance variables are marked private, encapsulation has been achieved. Encapsulation is a method of abstraction that hides implementation details from the user of a class. Encapsulation means that an attribute cannot be modified after creation. Encapsulation helps developers write reusable and maintainable code. ☐ Encapsulation means that an object can take on several forms. For example, a Lion is both a Feline and an Animal, Question 17 2 pts Consider the following class: 1 public class IntervalTimer { 2 public int elapsed = 0; public final int interval; 6 public IntervalTimer (int interval) { 7 this.elapsed = 0; 8 this.interval= interval; 9 } 10 11 public void tick () { 12 if (++elapsed EE interval) { 13 14 15 } 16 } 17 } Select all statements that are true: The class violated the principle of information hiding. The class uses delegation. Line 12 is logically incorrect. No statement is correct. This is a complete Java application. 3 4 5 2 pts System.out.println("Interval elapsed"); elapsed = 0;

Question 20 2 pts Which one of the following statements is NOT true about abstract classes: Abstract classes cannot have static attributes. Abstract classes can contain non-abstract methods. Abstract classes can have a constructor. O Methods defined in concrete classes have priority over methods in parent classes with the same method signature.