Deck 13: Interfaces and Inner Classes

Question 1

In Java,a derived class can have ________ base classes).

A)one
B)two
C)three
D)there is no limit

Answer 1

A

Question 2

An interface is a type.

Answer 2

True

Question 3

The Comparable interface is in the ______________ package.

A)java.util
B)java.io
C)java.awt
D)java.lang

Answer 3

D

Question 4

A class that implements an interface but only gives definitions for some of the method headings given in the interface is called a/an:

A)concrete class
B)abstract class
C)discrete class
D)friendly class

Question 5

If an inner class contains non static members,then the class name must be modified by the keyword:

A)Final
B)Static
C)Void
D)Protected

Question 6

The method that must be implemented in a class using the Comparable interface is:

A)public Object compareToObject other)
B)public Boolean compareToObject other)
C)public int compareToObject other)
D)none of the above

Question 7

An interface and all of its method headings are normally declared to be:

A)public
B)private
C)protected
D)package access

Question 8

An interface specifies the headings and definitions for methods that must be defined in any class that implements the interface.

Question 9

Any constant variables defined in an interface must be defined as:

A)public
B)private
C)protected
D)package access

Question 10

You can not derive an interface from a base interface.

Question 11

A class may only implement one interface.

Question 12

Java interfaces are a way of simulating multiple inheritance.

Question 13

Inner classes available outside the scope of their outer class are modified by the keyword:

A)Public
B)Private
C)Protected
D)Package access

Question 14

An interface may contain:

A)instance variables
B)primitive variables
C)constant variables
D)all of the above

Question 15

When defining an inner class to be a helper class for an outer class,the inner classes access should be marked as:

A)Public
B)Private
C)Protected
D)Package access

Question 16

A class that uses an interface must use the keyword:

A)Extends
B)Inherits
C)Super
D)Implements

Question 17

The compareTo method should return _____________ if the calling object equals the parameter.

A)A negative number
B)Zero
C)A positive number
D)Null

Question 18

When using the clone method from an inherited base class you should account for a _________ exception.

A)CloneNotFoundException
B)CloneEmptyException
C)CloneNotSupportedException
D)CloneNotEmptyException

Question 19

A common use of inner classes is :

A)clean up
B)set up
C)helper
D)all of the above

Question 20

A Java interface is an example of:

A)encapsulation
B)abstraction
C)polymorphism
D)all of the above

Question 21

What are the semantics of the Comparable interface?

Question 22

An interface can contain defined constants as well as method headings or instead of method headings.

Question 23

Java source code that contains a class with an inner class,when compiled,will produce a separate .class file for the inner class.

Question 24

What are the rules of total ordering?

Question 25

Why does Java only allow the inheritance of only one base class?

Question 26

Inner and outer classes do not have access to each other's private members.

Question 27

The Serializable interface is like all the other Java interfaces in that it contains defined constants and method headings.

Question 28

The compiler and the run-time system enforces semantics on the Comparable interface.

Question 29

What are two advantages to using inner classes?

Question 30

An inner class definition is local to the outer class definition.

Question 31

What is an anonymous class?

Question 32

What are the obligations of a class that implements a specific interface?