Answer the correct option.

Question 5

What can an abstract class contain?

Question 5 options:

	constructors, instance variables, instance methods, abstract methods, static methods, static variables
	constructors, instance variables, instance methods, abstract methods,
	abstract methods, static methods, static variables
	instance variables, instance methods, abstract method

Question 6

What is the use of the keyword super in a subclass?

Question 6 options:

	It provides access to the constructor of the superclass.
	It provides access to an instance method of the superclass.
	It provides access to a public instance variable of the superclass.
	All of the above.
	None of the above

Question 7

What is the purpose of a constructor in a subclass.

Question 7 options:

	To initialize value of the subclasses' private and public instance variable through assignment statements (eg. this.x = 1)
	To initialize the value of the subclasses' public and private instance variables and the superclasses' private and public instance variables through assignment statements. (super.x = 1; this.y = 2)
	To use a super constructor to initialize the value of the superclasses' instance variables.
	To initialize value of the subclasses' private and public instance variable through assignment statements (eg. this.x = 1) and use a super constructor to initialize the value of the superclasses' instance variables.

Question 8

Abstract classes can not be instantiated.

Question 8 options:

	True
	False

Question 9

Which of the following is a correct implementation of polymorphism. Note, object B extends object A.

Question 9 options:

	B obj1 = new A();
	A ob1 = new A();
	B obj1 = new B();
	A obj1 = new B();

Question 10

Interfaces differ from Abstract class because:

Question 10 options:

	a class can implement many interfaces, but can only extend one abstract class
	abstract classes create a hierarchy but interfaces do not
	interfaces can only contain abstract methods and no implementations
	all of the above

Question 11

Given this code snippet,

public class Person { public String name; public Person(String name) { System.out.println(name); this.name = name; } public void printName() { System.out.println(this.name); } } public class Miner extends Person { public Miner(String name) { super(name); } }

what will this program print?

Person somePerson = new Person("Bob"); Miner mikeTheMiner = new Miner("Mike"); mikeTheMiner.printName();

Question 11 options:

	This code causes an error.
	Mike Mike Bob
	Bob Mike Mike
	Bob
	Bob Mike Bob

Question 12

Based on this code snippet

public class Shape { public String getShapeName() { return "Shape"; } } public class Rectangle extends Shape {} public class Square extends Rectangle {} public class Oval extends Shape { public String getShapeName() { return "Oval"; } } public class Circle extends Oval { public String getShapeName() { return "Circle"; } }

what does this program output?

Shape shape1 = new Shape(); Shape shape2 = new Rectangle(); Shape shape3 = new Square(); Shape shape4 = new Circle(); System.out.println(shape1.getShapeName()); System.out.println(shape2.getShapeName()); System.out.println(shape3.getShapeName()); System.out.println(shape4.getShapeName());

Question 12 options:

	Shape Rectangle Rectangle Circle
	Shape Shape Shape Shape
	Shape Shape Shape Circle
	This code will error
	Shape Rectangle Square Circle
	Shape Rectangle Rectangle Oval