ICSI 213: chapter 10 - inheritance (interface and polymorphism)

If a subclass constructor does not explicitly call a superclass constructor

Java will automatically call the superclass's default or no-arg constructor just before the code in the subclass's constructor executes

In an inheritance relationship

The superclass constructor always executes before the subclass constructor

In UML diagrams, inheritance is shown

With a line that has an open arrowhead at one end that points to the superclass

If a class contains an abstract method

You cannot create an instance of the class, the method will have only a header, but not a body, and end with a semicolon and the method must be overridden in subclasses

If ClassC extends ClassB, which extends ClassA, this would be an example of

a chain of inheritance

When an "is a" relationship exists between objects, it means that the specialized object has

all the characteristics of the general object, plus additional characteristics

All fields declared in an interface

are final and static

Like a family tree, a ________ shows the inheritance relationship between classes

class hierarchy

An anonymous inner class must

implement an interface or extend another class

In a class hierarchy:

the more general classes are toward the top of the tree and the more specialized are toward the bottom

If a superclass does not have a default constructor or a no-arg constructor

then a class that inherits from it, must call one of the constructors that the superclass does have

What is required for an interface method that has a body

The method header must begin with the key word default

If you do not provide an access specifier for a class member, the class member is given ________ by default.

package

A subclass may call an overridden superclass method by

prefixing its name with the super key word and a dot (.)

Which of the following is TRUE about protected access? A) Protected members may be accessed by methods in the same package or in a subclass, even when the subclass is in a different package. B) Protected members may be accessed by methods in the same package or in a subclass, but only if the subclass is in the same package. C) Protected members cannot be accessed by methods in any other classes. D) Protected members are actually named constants.

A) Protected members may be accessed by methods in the same package or in a subclass, even when the subclass is in a different package

When a subclass overloads a superclass method:

Both methods may be called with a subclass object

In the following statement, which is the subclass? public class ClassA extends ClassB implements ClassC

ClassA

In the following statement, which is the superclass? public class ClassA extends ClassB implements ClassC

ClassB

In the following statement, which is the interface? public class ClassA extends ClassB implements ClassC

ClassC

If a method in a subclass has the same signature as a method in the superclass, the subclass method overloads the superclass method

FALSE

If two methods in the same class have the same name but different signatures, the second overrides the first.

FALSE

In an inheritance relationship, the subclass constructor always executes before the superclass constructor.

FALSE

Inheritance involves a subclass, which is the general class, and a superclass, which is the specialized class.

FALSE

When an interface variable references an object, you can use the interface variable to call any and all of the methods in the class implementing the interface.

FALSE

Replacing inadequate superclass methods with more suitable subclass methods is known as what

Method overriding

Protected members are

Not quite private and not quite public

A subclass can directly access

Only public and protected members of the superclass

If ClassA extends ClassB, then

Public members in ClassB are public in ClassA, but private members in ClassB cannot be directly accessed in ClassA

When declaring class data members, it is best to declare them a

private members

In an interface all methods have

public access

Which of the following statements correctly specifies three interfaces

public class ClassA implements Interface1, Interface2, Interface3

Which of the following statements declares Salaried as a subclass of PayType

public class Salaried extends PayType

What key word can you use to call a superclass constructor explicitly

super

When one object is a specialized version of another object, there is this type of relationship between them

"is a"

Protected class members are denoted in a UML diagram with the symbol

#

This annotation tells the Java compiler that a method is meant to override a method in the superclass

@Override

All methods in an abstract class must also be declared abstract

FALSE

An abstract class is not instantiated, but serves as a superclass for other classes

TRUE

Every class has a toString method and an equals method inherited from the Object class.

TRUE

Every class is either directly or indirectly derived from the Object class

TRUE

It is not possible for a superclass to call a subclass's method

TRUE

Private members of the superclass cannot be accessed by the subclass

TRUE

When a subclass extends a superclass, the public members of the superclass become public members of the subclass

TRUE

When a method is declared with the ________ modifier, it cannot be overridden in a subclass

final

A protected member of a class may be directly accessed by

methods of the same class, methods of a subclass, and methods in the same package

The super statement that calls the superclass constructor

must be the first statement in the subclass's constructor

If two methods have the same name but different signatures, they are

overloaded

If a class contains an abstract method

The method will have only a header, but not a body, and end with a semicolon