Question 1

The capability to inherit from more than one class is called ____.
A) multiple inheritance
B) collision
C) polyinheritance
D) dynamic method binding

Accepted Answer

The capability to inherit from more than one class is called multiple inheritance. This allows a subclass to have characteristics of multiple parent classes.

Question 2

The Object class contains a(n) ____________________ method that takes a single argument, which must be the same type as the type of the invoking object.

Accepted Answer

The answer of The Object class contains a(n) ____________________ method...

Question 3

Classes, such as the String class, have their own equals() methods that overload the ____ class method.
A) Object
B) Public
C) Abstract
D) Child

Accepted Answer

The equals() method in the String class (and other classes) overloads the Object class method. This means that the String class has its own implementation of equals() that is specific to strings, but if the equals() method is called on an object of type Object (which all classes inherit from), the default implementation from the Object class will be used.

Question 4

Abstract classes and methods appear in ____ in a class diagram.
A) bold
B) all caps
C) italics
D) blue

Accepted Answer

In a class diagram, abstract classes and methods are typically represented in italics to distinguish them from concrete classes and methods.

Question 5

The ___ method is useful in debugging a program because it can be used to display and examine values.
A) finalize()
B) toString()
C) notify()
D) equals()

Accepted Answer

The toString() method is commonly used in debugging to display the values of objects in a readable format. It can help developers identify errors and track down bugs more efficiently. The other methods listed (finalize(), notify(), and equals()) are also important in Java, but they are not typically used for debugging purposes.

Question 6

When you create a class and use the implements clause to implement an interface but fail to code one of the interface's methods, the compiler error generated indicates that you must declare your class to be ____.
A) abstract
B) static
C) public
D) related

Accepted Answer

If you fail to code one of the interface's methods, the class must be declared as abstract since abstract classes cannot be instantiated and must be subclassed to implement the missing methods.

Question 7

When a class both extends and implements, by convention the ____ clause is last in the class header.
A) extends
B) new
C) implements
D) if

Accepted Answer

By convention, the keyword "extends" comes first in the class header when a class extends another class, followed by the keyword "implements" to indicate that the class is implementing one or more interfaces. Therefore, the answer is C, as the convention dictates that the "implements" clause should come last in the class header if both "extends" and "implements" are present.

Question 8

In the Java programming language, a package or class library is often delivered to users as a(n) ____________________ file.

Accepted Answer

The answer of In the Java programming language, a package...

Question 9

Which of the following is NOT true regarding abstract methods?
A) Abstract methods must be implemented in child classes.
B) Abstract methods have no body.
C) Abstract methods use the abstract keyword in declarations.
D) Abstract methods are inherited by their children.

Accepted Answer

Abstract methods are declared in parent classes but have no implementation, and must be implemented in child classes. Child classes inherit the abstract method but must implement it themselves. Therefore, option D is incorrect as abstract methods are not inherited by their children without implementation.

Question 10

A(n) ____ looks much like a class, except that all of its methods (if any) are implicitly public and abstract.
A) hash code
B) package
C) collision
D) interface

Accepted Answer

The description matches that of an interface. The methods in an interface are by default public and abstract, and an interface can be seen as a template for classes to implement. A hash code is a numeric representation of an object, a package is a way of organizing related classes, and a collision refers to the situation where two or more objects have the same hash code.

Question 11

Java's Object class contains a public method named ____ that returns an integer representing the hash code.
A) length()
B) hashCode()
C) hcode()
D) toString()

Accepted Answer

The Object class in Java contains a public method named hashCode() which returns an integer representing the hash code of the object. This method can be overridden in subclasses to provide specific implementations for hashing. Option A is incorrect because the length() method returns the length of an array or string. Option C is not a valid method in the Object class. Option D returns the string representation of the object.

Question 12

When you create a new subclass in Java, neither the superclass source code nor the superclass _____ is changed.
A) bytecode
B) object
C) argument
D) possession

Accepted Answer

When creating a new subclass in Java, the superclass source code and bytecode are not changed, therefore choice A is the correct answer. The superclass object, argument, and possession are also not affected by the creation of a new subclass.

Question 13

____ compress the data they store, which reduces the size of archived class files.
A) Dynamic method bindings
B) JAR files
C) Type-import-on-demand declarations
D) Interfaces

Accepted Answer

JAR files are Java Archive files that act as a container for storing related class, image, and sound files. These files often use compression to reduce the size of archived class files, making them easier to transfer and store.

Question 14

The Object class equals() method returns a(n) ____ value indicating whether the objects are equal.
A) int
B) equals
C) null
D) boolean

Accepted Answer

The Object class equals() method returns a boolean value indicating whether the objects are equal.

Question 15

If you do not specify a package for a class, it is placed in an unnamed ____ package.
A) system
B) language
C) default
D) general

Accepted Answer

In Java, if you do not specify a package for a class, it is placed in the default package.

Question 16

When you create a number of classes that inherit from each other, as well as multiple interfaces that you want to implement with these classes, you often will find it convenient to place these related classes in a(n) ____________________.

Accepted Answer

The answer of When you create a number of classes...

Question 17

If Java did not allow you to ____ classes, you would need to create every part of a program from scratch.
A) extend
B) override
C) abstract
D) import

Accepted Answer

If Java did not allow you to extend classes, you would not be able to inherit properties and methods from existing classes, requiring the creation of every part of a program from scratch. Overriding, abstracting, and importing classes are not essential for this purpose.

Question 18

In other programming languages, such as C++, abstract classes are known as ____________________ classes.

Accepted Answer

The answer of In other programming languages, such as C++,...

Question 19

If you provide an empty method within an abstract class, the method is an abstract method even if you do not explicitly use the keyword ____________________ when defining the method.

Accepted Answer

The answer of If you provide an empty method within...

Question 20

____ provides a calculated hexadecimal number that is used to identify an object.
A) Method binding
B) A hash code
C) Implicit conversion
D) Ad-hoc polymorphism

Accepted Answer

A hash code is a calculated hexadecimal number that is used to identify an object. It is often used in hash tables and other data structures for efficient retrieval and storage of objects. Method binding refers to the process of associating a method with an object or class, while implicit conversion involves the automatic conversion of one data type to another. Ad-hoc polymorphism refers to the ability of a function or operator to behave differently depending on the types of arguments it is given.

Quiz 11: Advanced Inheritance Concepts

The capability to inherit from more than one class is called ____.

The Object class contains a(n) ____________________ method that takes a single argument, which must be the same type as the type of the invoking object.

Classes, such as the String class, have their own equals() methods that overload the ____ class method.

Abstract classes and methods appear in ____ in a class diagram.

The ___ method is useful in debugging a program because it can be used to display and examine values.

When you create a class and use the implements clause to implement an interface but fail to code one of the interface's methods, the compiler error generated indicates that you must declare your class to be ____.

When a class both extends and implements, by convention the ____ clause is last in the class header.

In the Java programming language, a package or class library is often delivered to users as a(n) ____________________ file.

Which of the following is NOT true regarding abstract methods?

A(n) ____ looks much like a class, except that all of its methods (if any) are implicitly public and abstract.

Java's Object class contains a public method named ____ that returns an integer representing the hash code.

When you create a new subclass in Java, neither the superclass source code nor the superclass _____ is changed.

____ compress the data they store, which reduces the size of archived class files.

The Object class equals() method returns a(n) ____ value indicating whether the objects are equal.

If you do not specify a package for a class, it is placed in an unnamed ____ package.

When you create a number of classes that inherit from each other, as well as multiple interfaces that you want to implement with these classes, you often will find it convenient to place these related classes in a(n) ____________________.

If Java did not allow you to ____ classes, you would need to create every part of a program from scratch.

In other programming languages, such as C++, abstract classes are known as ____________________ classes.

If you provide an empty method within an abstract class, the method is an abstract method even if you do not explicitly use the keyword ____________________ when defining the method.

____ provides a calculated hexadecimal number that is used to identify an object.