Java CH 6

Java allows you to create objects of this class in the same way you would create primitive variables.

String

Instance methods do not have the key word static in their headers.

T

Which of the following are classes from the Java API?

a. Scanner b. Random c. PrintWriter

Look at the following statement. import java.util.Scanner; This is an example of

an explicit import

A class's responsibilities include:

both A and B

It is common practice in object-oriented programming to make all of a class's

fields private

A constructor:

has the same name as the class

Quite often you have to use this statement to make a group of classes available to a program

import

When an object is created, the attributes associated with the object are called:

instance fields

Methods that operate on an object's fields are called:

instance methods

The following package is automatically imported into all Java programs.

java.lang

A UML diagram does not contain:

object names

Most programming languages that are in use today are:

object-oriented

This is a group of related classes.

package

When you are working with a ____________, you are using a storage location that holds a piece of data.

primitive variable

The scope of a private instance field is:

the instance methods of the same class

When an object is passed as an argument to a method, what is passed into the method's parameter variable?

the object's memory address

Two or more methods in a class may have the same name as long as:

they have different parameter lists

What does the following UML diagram entry mean? + setHeight(h : double) : void

this is a public method with a parameter of data type double and does not return a value

In UML diagrams, this symbol indicates that a member is public.

+

In UML diagrams, this symbol indicates that a member is private:

-

What is stored by a reference variable?

A memory address

The java.lang package is automatically imported into all Java programs.

T

You should not define a class field that is dependent upon the values of other class fields:

in order to avoid having stale data

Instance methods do not have this key word in their headers:

static

Given the following code, what will be the value of finalAmount when it is displayed? public class Order { private int orderNum; private double orderAmount; private double orderDiscount; public Order(int orderNumber, double orderAmt, { double orderDisc) { orderNum = orderNumber; orderAmount = orderAmt; orderDiscount = orderDisc; } public double finalOrderTotal() { return orderAmount - orderAmount * orderDiscount; } } public class CustomerOrder { public static void main(String[] args) { Order order; int orderNumber = 1234; double orderAmt = 580.00; double orderDisc = .1; order = new Order(orderNumber, orderAmt, orderDisc); double finalAmount = order.finalOrderTotal(); System.out.println("Final order amount = $" + } } finalAmount); } }

522.00

This refers to the combining of data and code into a single object.

Encapsulation

Instance methods should be declared static.

F

The term "default constructor" is applied to the first constructor written by the author of a class.

F

Which of the following statements will create a reference, str, to the string, "Hello, world"? String str = new String("Hello, world"); String str = "Hello, world";

1 and 2

A method that gets a value from a class's field but does not change it is known as a mutator method.

F

The public access specifier for a field indicates that the attribute may not be accessed by statements outside the class.

F

When a local variable in an instance method has the same name as an instance field, the instance field hides the local variable.

F

Which of the following statements will create a reference, str, to the String, "Hello, World"?

String str = "Hello, World";

A class in not an object, but a description of an object.

T

A constructor is a method that is automatically called when an object is created.

T

A method that stores a value in a class's field or in some other way changes the value of a field is known as a mutator method.

T

An access specifier indicates how the class may be accessed.

T

An object can store data.

T

Shadowing is the term used to describe where the field name is hidden by the name of a local or parameter variable.

T

The term "no-arg constructor" is applied to any constructor that does not accept arguments.

T

Which of the following is not involved in finding the classes when developing an object-oriented application?

Write the code.

Look at the following statement. import java.util.*; This is an example of:

a wildcard import

After the header, the body of the method appears inside a set of:

braces, {}

One or more objects may be created from a(n):

class

A class specifies the ________ and ________ that a particular type of object has.

fields; methods

Overloading means multiple methods in the same class

have the same name, but different parameter lists

Another term for an object of a class is

instance

Class objects normally have __________ that perform useful operations on their data, but primitive variables do not.

methods

A constructor is a method that:

performs initialization or setup operations.

The scope of a public instance field is:

the instance methods and methods outside the class

In a UML diagram to indicate the data type of a variable enter:

the variable name followed by a colon and the data type

Data hiding, which means that critical data stored inside the object is protected from code outside the object, is accomplished in Java by:

using the private access specifier on the class fields

For the following code, which statement is not true? public class Circle { private double radius; public double x; private double y; }

y is available to code that is written outside the Circle class.

For the following code, which statement is not true? public class Sphere { private double radius; public double x; private double y; private double z; }

z is available to code that is written outside the circle class.

In your textbook the general layout of a UML diagram is a box that is divided into three sections. The top section has the _______; the middle section holds _______; the bottom section holds _______.

class name; attributes or fields; methods

In the cookie cutter metaphor, think of the ________ as a cookie cutter and ________ as the cookies.

class; objects