2.18 Jb0180r review

Revised: Mon Mar 28 11:31:59 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
• Answers
• Miscellaneous

Preface

This module contains review questions and answers keyed to the module titled Jb0180: Java OOP: The main method .

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 .

Write the method signature for the main method in a Java application.

Answer 1

Question 2

Briefly explain the reason that the main method in a Java application is declared public .

Answer 2

Question 3

Explain the reason that the main method in a Java application must be declared static .

Answer 3

Question 4

Describe the purpose of the keyword void when used as the return type for the main method.

Answer 4

Question 5

True or false? If the Java application is not designed to use command-line arguments, it is not necessary to include a formal parameter for the main method.

Answer 5

Question 6

True or false? When using command-line arguments in Java, if the name of the string array is args , the args.length variable can be used by the code in the program to determine the number of arguments actually entered.

Answer 6

Question 7

True or false? The first string in the array of command-line arguments contains the name of the Java application

Answer 7

Question 8

The controlling class of every Java application must contain a main method. Can other classes in the same application also have a main method? If not, why not? If so, why might you want to do that?

Answer 8

What is the meaning of the following two images?

This image was inserted here simply to insert some space between the questions and the answers to keep them from being visible on the screen at thesame time.

The image is also an example of the kinds of things that we do in my course titled ITSE 2321, Object-Oriented Programming.

This image was also inserted for the purpose of inserting space between the questions and the answers.

Answers

Answer 8

Any and all classes in a Java application can have a main method. Only the one in the controlling class for the program being executed is actually called.

It is often desirable to provide a main method for a class that will not ultimately be the controlling class to allow the class to be tested in a stand-alone mode, independent of other classes.

Back to Question 8

Answer 7

False. Unlike C++, the first string in the array of command-line arguments in a Java application does not contain the name of the application.

Back to Question 7

Answer 6

True.

Back to Question 6

Answer 5

False. The main method in a Java program must always provide the formal argument list regardless of whether it is actually used in the program.

Back to Question 5

Answer 4

The void keyword when used as the return type for any Java method indicates that the method does not return anything.

Back to Question 4

Answer 3

The keyword static indicates that the method is a class method which can be called without the requirement to instantiate an object of theclass. This is used by the Java virtual machine to launch the program by calling the main method of the class identified in the command to start the program.

Back to Question 3

Answer 2

The keyword public indicates that the method can be called by any object.

Back to Question 2

Answer 1

Back to Question 1

Miscellaneous

This section contains a variety of miscellaneous information.

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