Quiz Questions for APCSA Unit 7
Questions and Code Cells for the Quiz on Unit 7
Unit 7: ArrayList
How do you create an ArrayList of Strings in Java?
a) ArrayList
b) ArrayList
c) ArrayList
d) ArrayList list = new ArrayList
Answer: b) ArrayList
Which method is used to add an element to an ArrayList?
a) add()
b) insert()
c) append()
d) push()
Answer: a) add()
What is the output of the following code?
ArrayList<Integer> list = new ArrayList<>();
list.add(10);
list.add(20);
System.out.println(list.get(1));
a) 10
b) 20
c) 1
d) Compile-time error
Answer: b) 20
Unit 8: 2D Array
How do you declare a 2D array of integers in Java?
a) int[][] array;
b) int array[][];
c) int[] array[];
d) All of the above
Answer: d) All of the above
What is the output of the following code?
int[][] arr = { {1, 2}, {3, 4} };
System.out.println(arr[1][0]);
a) 1
b) 2
c) 3
d) 4
Answer: c) 3
Which of the following correctly initializes a 2D array with 3 rows and 4 columns?
a) int[][] arr = new int[3][4];
b) int[] arr = new int[3][4];
c) int[][] arr = new int[4][3];
d) int[] arr = new int[4][3];
Answer: a) int[][] arr = new int[3][4];
Unit 9: Inheritance
Which keyword is used to inherit a class in Java?
a) inherits
b) extends
c) implements
d) super
Answer: b) extends
What is the correct way to call a parent class’s constructor in a subclass?
a) super();
b) parent();
c) base();
d) this();
Answer: a) super();
Which of the following statements about inheritance is true?
a) A subclass can inherit private members of a superclass.
b) A subclass cannot override methods of a superclass.
c) A subclass can only have one superclass.
d) A subclass must have the same name as the superclass.
Answer: c) A subclass can only have one superclass.
Unit 10: Recursion
Which of the following is an example of a recursive method?
a) A method that calls itself
b) A method that calls another method
c) A method that runs indefinitely
d) A method that returns a value
Answer: a) A method that calls itself
What is the base case in a recursive method?
a) The condition under which the method stops calling itself
b) The first call to the recursive method
c) The last call to the recursive method
d) The condition under which the method calls itself
Answer: a) The condition under which the method stops calling itself
What will be the output of the following recursive method when called with factorial(3)?
public int factorial(int n) {
if (n == 0) {
return 1;
}
return n * factorial(n - 1);
}
a) 6
b) 3
c) 0
d) 1
Answer: a) 6