2.20 Jb0190r: review

Revised: Mon Mar 28 11:58:41 CDT 2016

This page is included in the following Books:

• Programming Fundamentals with Java
• Object-Oriented Programming (OOP) with Java

Table of contents

• Preface
• Questions
  • 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18
• Answers
• Miscellaneous

Preface

This module contains review questions and answers keyed to the module titled Jb0190: Java OOP: Using the System and PrintStream Classes .

The questions and the answers are connected by hyperlinks to make it easy for you to navigate from the question to the answer and back again.

Questions

Question 1 .

True or false? The main method in the controlling class of a Java application controls the flow of the program.

Answer 1

Question 2

True or false? The main method cannot access the variables and methods of objects instantiated from other classes.

Answer 2

Question 3

True or false? The main method must instantiate objects of other classes in order for the program to execute.

Answer 3

Question 4

True or false? In order to be useful, the System class must be used to instantiate objects in a Java application.

Answer 4

Question 5

True or false? Class variables such as the out variable of the System class must be of some specific type.

Answer 5

Question 6

True or false? Class variables must be of a primitive type such as int or float .

Answer 6

Question 7

True or false? The out variable in the System class is of a primitive type.

Answer 7

Question 8

What does the following code fragment access?

Answer 8

Question 9

True or false? An object of type PrintStream is automatically instantiated when the System class is loaded into an application.

Answer 9

Question 10

True or false? The out variable in the System class refers to an instance of what class?

Answer 10

Question 11

True or false? The println method is an instance method of what class?

Answer 11

Question 12

What is the primary behavior of the println method?

Answer 12

Question 13

How can the println method be accessed?

Answer 13

Question 14

Assuming that the standard output device has not been redirected, write a code fragment that will cause your name to be displayed onthe screen.

Answer 14

Question 15

Explain how your code fragment in Answer 14 produces the desired result.

Answer 15

Question 16

If you have a class named MyClass that has a class variable named myClassVariable that requires four bytes of memory and you instantiate ten objects of type MyClass , how much total memory will be allocated to contain the allocated variables (assume that the class definition contains no other class, instance, or local variables) .

Answer 16

Question 17

How many actual instances of the variable named out are allocated in memory by the following code fragment?

Answer 17

Question 18

If you have a class named MyClass that has an instance variable named myInstanceVariable that requires four bytes of memory and you instantiate ten objects of type MyClass , how much total memory will be allocated to contain the allocated variables (assume that the class definition contains no other class, instance, or local variables) .