Inheritance

Question 1

What does a child class inherit from a parent class?

Answer 1

All fields and methods except constructors and final fields

Question 2

How can a child class create a new instantiation within the abstract parent class?

Answer 2

childConstructor( ){
super( )
}

Question 3

What is the rule about a child’s constructor calling a parents constructor using “super( )”

Answer 3

It must be the first statement in the child class’s constructor method

Question 4

If a parent class has constructor with argument but no constructor without argument, and a child class with argument is instantiated does this result in a compilation error?

Answer 4

Usually, unless the child with argument explicitly calls the parent with argument using super(argument)

Question 5

How can a parent access its child’s fields

Answer 5

It must be casted down to the child

Question 6

What types of methods cannot be overridden?

Answer 6

private, final or static

Question 7

where can a public member be accessed from?

Answer 7

within the same class, same package, a child class, or even from a different package

Question 8

where can a protected member be accessed from?

Answer 8

within the same class, same package, from a child class, NOT from a different package

Question 9

where can a default member be accessed from?

Answer 9

within the same class and the same package, but NOT from a child class or from a different package

Question 10

where can a private member be accessed from?

Answer 10

private can be accessed from within the same class only. NOT from within the same package, subclass or an different package

Question 11

Can abstract classes be instantiated?

Answer 11

No

Question 12

Can we make a reference variable of an abstract class?

Answer 12

Yes, to instantiate child classes from the parent abstract class

Question 13

What modifiers to abstract class constructors have?

Answer 13

Protected Modifier

Question 14

Can abstract classes contain both abstract and non-abstract methods?

Answer 14

Yes

Question 15

How do you declare an abstract method in an abstract class?

Answer 15

just the header followed by a semicolon
ex: public abstract abstractMethod( );