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Fundamentals of the Java

Programming Language,

Java SE 6

Volume I Activity Guide

SL-110-SE6 E.1 Rev E.1

D61796GC11

Edition 1.1

June 2010

D67897


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Copyright 2010, Oracle and/or its affiliates. All rights reserved.

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vCopyright 2007 SunMicrosystems, Inc. AllRightsReserved.SunServices, RevisionE.1

Table of Contents

Explaining Java Technology........................................................1-1Objectives ........................................................................................... 1-1Lab Overview ..................................................................................... 1-2Completing Review Questions ........................................................ 1-3Exercise Summary.............................................................................. 1-5

Analyzing a Problem and Designing a Solution............................2-1Objectives ........................................................................................... 2-1Lab Overview ..................................................................................... 2-2Completing Review Questions ........................................................ 2-3Exercise 1: Analyzing a Problem Domain ...................................... 2-4

Preparation................................................................................. 2-4Task Performing an Analysis ............................................... 2-4

Exercise 2: Designing a Solution...................................................... 2-6Task Producing a Design ...................................................... 2-6

Exercise Summary.............................................................................. 2-8

Developing and Testing a Java Technology Program..................3-1Objectives ........................................................................................... 3-1Lab Overview ..................................................................................... 3-2Completing Review Questions ........................................................ 3-3Exercise 1: Modifying, Compiling, and Executing a Java

Program............................................................................................ 3-4Preparation................................................................................. 3-4.Task Compiling and Executing a Java Program............... 3-4

Exercise 2: Creating, Compiling, and Executing a Java Class ..... 3-6

Task Creating a Java Class and Testing It .......................... 3-6Exercise Summary.............................................................................. 3-8

Declaring, Initializing, and Using Variables ...................................4-1Objectives ........................................................................................... 4-1Lab Overview ..................................................................................... 4-2


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vi Fundamentals of theJavaProgrammingLanguageCopyright2007 SunMicrosystems, Inc. AllRights Reserved.SunServices, RevisionE.1

Completing Review Questions ........................................................ 4-3Exercise 1: Using Primitive Type Variables in a Program ........... 4-5

Preparation................................................................................. 4-5Task Creating a Class With Variables ................................. 4-5

Exercise 2: Using Operators and Type Casting ............................. 4-6

Preparation................................................................................. 4-6Task 1 Calculating Age Using Operators ........................... 4-6Task 2 Using Casting to Prevent Data Loss ....................... 4-7Task 3 Creating a Temperature Program ...........................4-8


Creating and Using Objects............................................................ 5-1Objectives ........................................................................................... 5-1Lab Overview ..................................................................................... 5-2Completing Review Questions ........................................................ 5-3Exercise 1: Creating and Manipulating Java Technology

Objects............................................................................................... 5-4

Preparation................................................................................. 5-4Task 1 Initializing Object Instances ..................................... 5-4Task 2 Manipulating Object References.............................. 5-5

Exercise 2: Using theStringClass ................................................. 5-6Preparation................................................................................. 5-6Task Creating and UsingStringObjects .......................... 5-6

Exercise 3: Using the Java SE API Specification ........................ 5-7Task Examining the Java SE API Specification.................. 5-7


Using Operators and Decision Constructs ................................... 6-1

Objectives ........................................................................................... 6-1Lab Overview ..................................................................................... 6-2Completing Review Questions ........................................................ 6-3Exercise 1: Usingifandif/elseConstructs............................... 6-5

Preparation................................................................................. 6-5Task 1 Writing a Class That Usesif/elseStatements.... 6-5Task 2 Writing Another Class That Usesif/else

Statements ............................................................................... 6-6Exercise 2: Using theSwitch Statement......................................... 6-7

Preparation................................................................................. 6-7Task Writing a class That Uses theswitchStatement..... 6-7


Using Loop Constructs ................................................................... 7-1Objectives ........................................................................................... 7-1Lab Overview ..................................................................................... 7-2Completing Review Questions ........................................................ 7-3Exercise 1: Using thewhileLoop.................................................... 7-4

Preparation................................................................................. 7-4


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viiCopyright 2007 SunMicrosystems, Inc. AllRightsReserved.SunServices, RevisionE.1

Task 1 Writing a Class That Uses awhileLoop ............... 7-4Task 2 Writing Another Class That Uses awhileLoop .. 7-5

Exercise 2: Using theforloop ......................................................... 7-7Preparation................................................................................. 7-7Task 1 Writing a Class That Uses theforLoop................ 7-7

Task 2 Modifying awhileLoop to aforLoop.................7-8Exercise 3: Using thedo/whileLoop............................................. 7-9Preparation................................................................................. 7-9Task Writing a Class Using thedo/whileLoop............... 7-9

Exercise Summary............................................................................ 7-10

Developing and Using Methods......................................................8-1Objectives ........................................................................................... 8-1Lab Overview ..................................................................................... 8-2Completing Review Questions ........................................................ 8-3Exercise 1: Using Arguments and Return Values ......................... 8-4

Preparation................................................................................. 8-4

Task Writing a Method That Uses Arguments and ReturnValues ...................................................................................... 8-4

Exercise 2: Using Overloaded Methods.......................................... 8-6Preparation................................................................................. 8-6Task Developing a Class With an Overloaded Method... 8-6


Implementing Encapsulation and Constructors............................9-1Objectives ........................................................................................... 9-1Lab Overview ..................................................................................... 9-2Completing Review Questions ........................................................ 9-3

Exercise 1: Writing Encapsulated Classes ...................................... 9-4Preparation................................................................................. 9-4Task 1 Implementing Encapsulation in a Class................. 9-4Task 2 Accessing Encapsulated Attributes of a Class....... 9-5

Exercise 2: Using Constructors......................................................... 9-8Preparation................................................................................. 9-8Task 1 Creating and Using Constructors............................ 9-8Task 2 Creating Constructors to Initialize Objects............ 9-9


Creating and Using Arrays ............................................................10-1

Objectives ......................................................................................... 10-1Lab Overview ................................................................................... 10-2Completing Review Questions ...................................................... 10-3Exercise 1: Creating and Using One-Dimensional Arrays......... 10-4

Preparation............................................................................... 10-4Task 1 Creating a Class With a One-Dimensional Array of

Primitive Types .................................................................... 10-4


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viii Fundamentals of the Java Programming LanguageCopyright2007 SunMicrosystems, Inc. AllRights Reserved.SunServices, RevisionE.1

Task 2 Creating a Class With a One-Dimensional Array ofObjects.................................................................................... 10-5

Exercise 2: Using Loops and Arrays.............................................. 10-7Preparation............................................................................... 10-7Task Using a Loop to Initialize an Array.......................... 10-7

Exercise 3: Parsing theargs[]Array ........................................... 10-8Task Creating a Game Using theargs [ ]Array............10-8Exercise 4: Creating and Using Two-Dimensional Arrays ........ 10-9

Preparation............................................................................... 10-9Task 1 Creating a Class With a Two-Dimensional

Array .................................................................................... 10-10Task 2 Traversing a Two-Dimensional Array................ 10-10Task 3 Testing a Class Having a Two-Dimensional

Array .................................................................................... 10-12Exercise Summary.......................................................................... 10-13

Implementing Inheritance ............................................................. 11-1

Objectives ......................................................................................... 11-1Lab Overview ................................................................................... 11-2Completing Review Questions ...................................................... 11-3Exercise 1: Designing Superclasses and Subclasses .................... 11-4

Task 1 Identifying Superclasses and Subclasses.............. 11-4Exercise 2: Creating and Using Superclasses and Subclasses....11-6

Preparation............................................................................... 11-6Task Creating Classes.......................................................... 11-6



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1-1Copyright2007 SunMicrosystems, Inc. AllRights Reserved.SunServices,RevisionE.1

Lab 1

ExplainingJavaTechnology

Objectives

Upon completion of this lab, you should be able to complete the reviewquestions.


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Lab Overview

1-2 Fundamentals of the Java Programming LanguageCopyright2007 SunMicrosystems, Inc. AllRights Reserved.SunServices,RevisionE.1

Lab Overview

This lab does not have any exercises. You complete the review questionsin this module.


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Completing Review Questions

Explaining Java Technology 1-3Copyright2007 SunMicrosystems, Inc. AllRightsReserved. SunServices,RevisionE.1


In this section, you answer questions about the material covered inModule 1 of the Student Guide.

Complete the following questions:

1. The Java programming language is said to be platform-independent because:

a. Compiles on several platforms without modification

b. Does not allow pointers to be used to manipulate memory

c. Allows developers to create applications once that execute onseveral platforms

d. Is multithreaded

2. State whether the following statement is true or false:An application runs within an operating system.

3. The Java programming language is loosely based upon which of thefollowing languages:

a. C++

b. C

c. Machine Language

d. Fortran

4. The Java technology product group designed for developingapplications for consumer devices is _______. Choose one from thelist to fill in the blank:

a. Java SE SDK

b. Java ES SDK

c. Java EE SDK

d. Java ME SDK


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5. Which of the following is part of the Java SE SDK

a. The Java Runtime Environment

b. The Java Virtual Machine Specification

c. A C++ Compiler

d. A linker

6. In which stage of the PLC, developers create updates to theirproducts.

a. Analysis

b. Maintenance

c. EOL

d. Design

7. The implementation stage of PLC is usually synonymous with:

a. Selling your program

b. Executing your program

c. Compiling your program

d. Maintaining your program


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Exercise Summary

Explaining Java Technology 1-5Copyright2007 SunMicrosystems, Inc. AllRightsReserved. SunServices,RevisionE.1

Exercise Summary

?

!

Discussion Take a few minutes to discuss what experiences, issues, ordiscoveries you had during the lab exercises.

Experiences

Interpretations

Conclusions

Applications


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Lab 2

AnalyzingaProblemandDesigningaSolution

Objectives

Upon completion of this lab, you should be able to:

Complete Review Questions Analyze a problem using object-oriented analysis (OOA)

Design classes from which objects will be created


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Lab Overview


Lab Overview

In this lab, you complete review questions and two exercises.

The exercises are:

List the objects, attributes, and operations in a sample problemdomain

Model an object using an UML-like notation


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Analyzing a Problem and Designing a Solution 2-3Copyright2007 SunMicrosystems, Inc. AllRightsReserved. SunServices,RevisionE.1



1. Which of the following terms refers to the scope of a problem or a

system:a. The problem context

b. The problem domain

c. The system context

d. The problem area

2. Which of the following terms represents two different characteristicsof an object:

a. Methods and operations

b. The problem domain

c. Attributes and operations

d. Variables and data

3. Which of the following statements is a criteria to test the validity ofan object relative to a problem domain:

a. Relevance to the problem domain

b. Operation order

c. Attribute type

d. If a class has a super class

4. Which of the following statements are true:

a. A class is an instance of an object.

b. An object is a blueprint for a class.

c. An object and a class are exactly the same.

d. An object is an instance of a class.

e. An attribute cannot be a reference to another object.


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Exercise1: Analyzing a Problem Domain


Exercise 1: Analyzing a Problem Domain

This exercise is based on a small case study. You will identify the objects,their attributes and operations involved in the system domain.

Preparation

Read the following case study, and then model the system by choosingobjects and their attributes and operations.

Case Study

A soccer league has many players. Each year there are three seasons andthe league puts together teams for each season. Each team is comprised of15 players. The goals scored by each player during each season aretracked. The games played between the teams, their final scores, and eachteams standings based on its won and lost games are tracked.

Task Performing an Analysis

Your task is to produce an object-oriented analysis for a Java technologyapplication that tracks soccer scores. The program should track:

The list of players on each team

The number of goals that each player scores

The games played during a season, including the teams that playeach other, and the final score

The application should be able to generate statistics for teams, players,and seasons.

To finalize the analysis, complete the following steps:

1. Create a list of the potential objects.

2. Apply the rules in this module to decide if all your objects are valid.

3. Create a list of attributes and operations for each of your objects.


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Exercise 1: Analyzing a Problem Domain


Notes


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Exercise2: Designing a Solution


Exercise 2: Designing a Solution

In this exercise you will use UML notation to represent a class.

Task Producing a Design

Your task is to produce a design for each of the classes in the earliersystem for tracking soccer scores. Remember to:

Use short-hand to name your classes, attribute variables, andmethods

Identify a valid range of values for each attribute (where a range isknown)

Use the parentheses to identify methods


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Exercise 2: Designing a Solution


Notes


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Lab 3

Developing andTestingaJava TechnologyProgram

Objectives


Complete review questions Write, modify, compile, and execute Java technology classes


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Lab Overview


Lab Overview

In this lab, you complete the review questions and two exercises.

In the first exercise, you compile and execute an existing Java

technology class. In the second exercise, you write, compile, and execute your first

Java technology class.


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Developing and Testing a Java Technology Program 3-3Copyright2007 SunMicrosystems, Inc. AllRightsReserved. SunServices,RevisionE.1



1. Which of the following options is part of the class declaration syntax:

a. Class arguments

b. Method identifier

c. Modifier

d. //

2. Identify the statement below that best describes the main method:

a. Themainmethod is the starting point for all Java technologyapplets.

b. Themainmethod usually has a return type ofint.

c. Themainmethod is required in all Java classes.

d. Themainmethod is a special method that the Java VirtualMachine recognizes as the starting point for every Javatechnology program run from a command line or a prompt.

3. State whether the following statements are true or false:

a. Thejavacommand executes a class or bytecode file.

b. Every open curly bracket in a Java technology program musthave a corresponding closing curly brace.

c. */ is a valid starting delimiter for a comment.

d. Thejavaccommand reads class and interface definitions,written in the Java programming language, and compiles theminto bytecode class files.


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Exercise1: Modifying, Compiling, andExecuting a Java Program


Exercise 1: Modifying, Compiling, and Executing a JavaProgram

A Java technology program is already created for you. You need to open

it, examine the lines of code, modify it, compile it, and then test it byexecuting the program.

Preparation

Ensure thatQuotationTest.javaandQuotation.javafiles exist inSL110/exercises/03_getstarted/exercise1directory

.Task Compiling and Executing a Java Program

In this task, you will modify a Java Program, save, compile and test it.

Complete the following steps:

1. Open a text editor.

2. Open the Quotation.java file located atSL110/exercises/03_getstarted/exercise1directory.

3. Examine the Quotation class and identify its member variable.

4. In thedisplaymethod, write code to display the value of themember variable.

5. Save and close theQuotation.javafile.

6. Open theQuotationTest.javafile located atSL110/exercises/03_getstarted/exercise1directory andexamine itsmainmethod. The main method creates an instance ofthe Quotation class and executes thedisplaymethod ofQuotation.Close the file.

7. Open the terminal window and navigate to the directorySL110/exercises/03_getstarted/exercise1

.8. CompileQuotation.javafile usingjavac. Foe example:

javac Quotation.java


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Exercise 1: Modifying, Compiling, andExecuting a Java Program


9. If required, modify theQuotation.javafile to correct anycompilation errors generated by the previous step. Save the file andrecompile it.

10. CompileQuotationTest.javafile usingjavac. For example:javac QuotationTest.java

11. Examine theSL110/exercises/03_getstarted/exercise1directory to verify if the compilation steps has created the followingclass files:

Quotation.class

QuotationTest.class.

12. ExecuteQuotationTest.class file using java and verify the output.For example: java QuotationTest

13. OpenQuotation.java file, modify the default value of the member

variable inQuotation.javafile to your own favourite quotation,and save the file.

14. CompileQuotation.javafile.

15. ExecuteQuotationTest.classfile and verify the changed output.


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Exercise2: Creating, Compiling, and Executing a Java Class


Exercise 2: Creating, Compiling, and Executing a JavaClass

In this exercise you will create a Java class, and compile it. You will also

create another Java class to test the previous class.

Task Creating a Java Class and Testing It

In this task, you will create two classes and compile them. You willexecute one class file.


1. Go to theSL110/exercises/03_getstarted/exercise2directory.

2. Open an editor, and enter in the Java technology syntax for theShirtclass shown inCode 3-1 on page 3-8of this module of theStudent Guide.

3. Save and close the file.

4. Open an editor, and enter theShirtTest class shown inCode 3-2 onpage 3-14this module of the Student Guide.

5. Save and close the file.

6. Open a terminal window and navigate to the directory for thismodule.

7. Type the command to compile theShirtclass into an executablebytecode file. For example:javac Shirt.java

8. Verify that the fileShirt.classis created in theSL110/exercises/03_getstarted/exercise2directory.

9. Type the command to compile theShirtTest class into anexecutable bytecode file.javac ShirtTest.java

10. Verify that the fileShirtTest.class

is created in theSL110/exercises/03_getstarted/exercise2directory.

11. Type the command to run theShirtTest.classfile and examinethe output of the program.java ShirtTest

12. Open theShirt.javafile in the editor again.

13. Modify the values of theShirtID andpricemember variables.
http://../SL110_IG/mod03_getstartedjava.pdfhttp://../SL110_IG/mod03_getstartedjava.pdfhttp://../SL110_IG/mod03_getstartedjava.pdfhttp://../SL110_IG/mod03_getstartedjava.pdfhttp://../SL110_IG/mod03_getstartedjava.pdfhttp://../SL110_IG/mod03_getstartedjava.pdf


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Exercise 2: Creating, Compiling, andExecuting a Java Class


14. Save and close theShirt.javafile.

15. RecompileShirt.javafile at the terminal window.javac Shirt.java

16. Run theShirtTest.classfile at the terminal window.java Shirt

17. Examine the output of the program and verify if the output is differsfrom the output as seen in Step 9.


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Exercise Summary


Exercise Summary

?

!


Experiences

Interpretations

Conclusions

Applications


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Lab 4

Declaring, Initializing,andUsingVariables

Objectives


Complete review questions

Perform variable declarations in a class

Perform type casting and use operators in a Java technologyprogram


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Lab Overview


Lab Overview

In this lab, you complete review questions and two exercises.

In the first exercise, you create a Java class containing variable

declarations. In the second exercise, you write a Java technology program in

which you use operators and perform type casting.


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Declaring, Initializing, and Using Variables 4-3Copyright2007 SunMicrosystems, Inc. AllRightsReserved. SunServices,RevisionE.1




a. There are eight primitive types built into the Java programminglanguage.

b. In the Java programming language, the variable namesintgradeandintGradeare the same.

c. byte, short, int and long are the four integral primitive types inthe Java programming language.

d. A boolean type variable holds true, false and nil.

2. Which answer best describes the following variable declaration:final double PI = 3.14159;

a. This is the value assignment for an integral primitive type.

b. The name of the variable is a Java programming languagekeyword.

c. The variable is a constant.

d. The variable is incorrectly named, according to the namingguidelines.

3. Which of the following operations correctly illustrate operatorprecedence in the following calculation

X = 1 + 2 * 5 -8 +6 / 7 * 4;a. (1 + 2) * (5 - 8) + (6 / (7 * 4))

b. 1 + (2 * 5) - 8 + ((6 / 7) * 4)

c. (1 + 2) * (5 - ((8 + 6) / (7 * 4)))

d. 1 + (2 * (5 - 8)) + ((6 / 7) * 4)


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4. Examine the following code, and select the correct output afterexecution:int a = 5;

int b = ++a;System.out.println("a = "+ a + "and b = "+ b);

a. a = 5andb = 5

b. a = 5andb = 6

c. a = 6andb = 6

d. a = 6andb = 5


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Exercise 1: Using Primitive Type Variables in a Program


Exercise 1: Using Primitive Type Variables in a Program

In this exercise, you create a class containing variable declarations.

Preparation

Ensure thatCustomerTest.javafiles exists in theSL110/exercises/04_variables/exercise1directory.

Task Creating a Class With Variables

In this task, you compile and execute aCustomerclass with severalvariables.

Complete the following steps to create yourCustomerclass:.

1. Go to theSL110/exercises/04_variables/exercise1directory.

2. Open a text editor, and create a file in this directory calledCustomer.java.

3. In theCustomer.java file, write a class calledCustomer that createsand assigns default values to the variables for the followinginformation (use constants if appropriate):

A customer ID The customer status of N for new or O for old

Total purchases for the year

4. Create a method within the class calleddisplayCustomerInfothatuses theSystem.out.printlnmethod to print each value to thescreen with a corresponding label (such as"Purchases are: ").

5. Compile and run the program using the providedCustomerTestclass file.

Note All of the examples and exercises in this course require a test class.In most situations, the test class is provided. However, in some situations,you will create the class.

6. Check the output to be sure that it contains the values you assigned


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Exercise2: Using Operators and Type Casting


Exercise 2: Using Operators and Type Casting

The objective of this exercise is to give you practice using operators andtype casting.

This exercise has three tasks. In each of the tasks you create one Javatechnology program, compile it, and test it.

This exercise consists of the following tasks:

Task 1 Calculating Age Using Operators

Task 2 Using Casting to Prevent Data Loss

Task 3 Creating a Temperature Program

Preparation

Ensure that thePersonTest.java, OrderTest.java, andTemperatureTest.javafiles exists in theSL110/exercises/04_variables/exercise2directory.

Task 1 Calculating Age Using Operators

In this task, you use operators to calculate age in minutes and

milliseconds.

Follow these steps to create aPersonclass that calculates various ages:

1. Open a terminal window and go to theSL110/exercises/04_variables/exercisedirectory.

2. Open a text editor and create aPersonclass in a file.

3. Add the following code to yourPersonclass:

a. Create member variables to store age in years, days, minutes,seconds, and milliseconds.

b. Set an initial value of 1 to the variable which stores the age inyears.


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Exercise 2: Using Operators and Type Casting


Note Ensure that you assign the correct data types for each variable andprovide meaningful names to all the variables.

c. Create acalculateAgemethod in thePersonclass.

d. In the method, calculate the age in days, minutes, seconds, andmilliseconds and assign the new values to the correspondingmember variables.

e. In the method, print out all the ages in various units, each in aseparate line with an appropriate message. For example: Youare 31536000 seconds old.

f. Save and close thePerson.javafile.

g. Compile the Person.javaand PersonTest.javafiles. Removethe compilation errors if any and recompile.

h. Test the program using thePersonTestclass.i. Perform tests, by setting the value of age as 1, 24, and 80 in the

Personclass.

Note For one year, the results should be: You are 365 days old. You are31536000 seconds old. You are 525600 minutes old. You are 31536000000milliseconds old. For 24 years, the results should be: You are 8760 daysold. You are 756864000 seconds old. You are 12614400 minutes old. Youare 756864000000 milliseconds old.

Task 2 Using Casting to Prevent Data Loss

In this task, you use casting to ensure that data loss does not occur in yourprograms.

Perform the following steps:

1. Create a class called Order that contains three member variables asfollows:

a. long orderValue=0

b. int itemQuantity=10000000

c. int itemPrice=555500

2. Create acalculateTotalmethod that will calculate the total ordervalue and print it. Ensure that you type cast the result of themultiplication before storing it in order value.


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Exercise2: Using Operators and Type Casting


3. Save and close theOrder.javafile.

4. CompileOrder.javaandOrderTest.javafile.

5. Test the program by runningOrderTest.classfile. Verify theresult oforderValueby performing the calculation in a calculator.

6. OpenOrder.javaand remove and type casting done in thecalculateTotalmethod. Save and close the file.

7. RecompileOrder.javafile and run theOrderTestclass again.

8. Compare the current result oforderValuewith the one obtained inStep 5.

9. Test the program by replacing the value of the integer membervariables ofOrderclass by:

a. One-digitinttypes

b. Five-digitinttypes

c. Nine-digitinttypesEnsure that you get the same result with the program as you dowhen doing each calculation using a calculator.

Task 3 Creating a Temperature Program

In this task, you write a program to convert temperature from fahrenheitto Celsius.

Write code to complete the following steps:

1. Create aTemperature class with a member variable which stores thetemperature in fahrenheit. Declare the variable with an appropriatedata type, such as int, float, or double.

2. Create acalculateCelsius method.

3. In thecalculateCelsiusmethod, use the following information toconvert the temperature value from fahrenheit to Celsius.

To convert from Fahrenheit to Celsius, subtract 32, multiply by

5, and divide by 9.4. Test the program using theTemperatureTestclass.

5. Ensure that you get the same result with the program as you dowhen doing the calculation using a calculator.

6. Test the program using several values of temperature.


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Exercise Summary


Exercise Summary

?

!


Experiences

Interpretations

Conclusions

Applications


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Lab 5

CreatingandUsingObjects

Objectives



Create and manipulate objects

Use theStringclass

Use the Java SE API


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Lab Overview


Lab Overview

In this lab, you complete review questions and three exercises.

In the first exercise, you create and manipulate Java technology

objects. In the second exercise, you create and use String objects.

in the third exercise, you get familiar with the Java API specification.


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Creating and Using Objects 5-3Copyright2007 SunMicrosystems, Inc. AllRightsReserved. SunServices,RevisionE.1


Complete the following questions

1. Which of the following lines of code instantiates aBoatobject and

assigns it to asailBoatobject reference?a. Boat sailBoat = new Boat();

b. Boat sailBoat;

c. Boat = new Boat()

d. Boat sailBoat = Boat();

2. Read the following code and identify the result from the optionsgiven below:

Clothing myHat = new Hat();

Clothing mySock = new Sock();myHat = mySock;

a. ThemyHatvariable now contains aSockobject.

b. ThemyHatvariable contains the same address as themySockvariable.

c. TheSockandHatvariables are the same.

d. ThemyHatvariable remains unchanged.

3. Which of the following statements are true?

a. The dot (.) operator creates a new object instance.

b. TheStringclass provides you with the ability to store asequence of characters.

c. The Java API specification contains documentation for all of theclasses in a Java technology product.

d. Stringtypes are unique because they are the only class thatallows you to build objects without using thenewkeyword.


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Exercise1: Creating andManipulating Java Technology Objects


Exercise 1: Creating and Manipulating Java TechnologyObjects

In this exercise, you create instances of a class and manipulate these

instances in several ways.

This exercise consists of the following tasks:

Task 1 Initializing Object Instances

Task 2 Manipulating Object References

Preparation

Ensure thatCustomer.javafiles exists in theSL110/exercises/05_objects/exercise1directory.

Task 1 Initializing Object Instances

You have been provided with theCustomer class. In this task, you create,compile, and execute aCustomerTestclass. In theCustomerTestclass,you create objects of theCustomerclass and set values to its membervariables.


1. Go to theSL110/exercises/05_objects/exercise1 directory andopen theCustomer.javafile.

2. Examine theCustomerclass, its member variables and its method.

3. Create new classCustomerTest and save it asCustomerTest.java.

4. Create the main method in theCustomerTestclass.

5. In the main method, perform the following:

a. Declare two instances ofCustomerclass.

b. Initialize the two instances of theCustomerclass using thenewoperator.


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Exercise 1: Creating and Manipulating Java Technology Objects


c. Assign values to the member variables of theCustomerinstance. Repeat the same for the secondCustomerobject butwith different values. For example:cObject1.customerID=1;

d. Invoke thedisplayCustomerInfomethod for each of the

Customerobjects

6. Save, compile and run the program.

7. Check the output to be sure that eachCustomerobject displays thedistinct values you assigned.

Task 2 Manipulating Object References

In this task, you assign the value of one object reference to another object

reference. Complete the following steps:1. OpenCustomerTest.java file, that you created and executed in the

previous task.

2. In themainmethod, go to the line where you invoke thedisplayCustomerInfomethod for both theCustomerinstances.

3. Assign one object reference to another object reference, before youcall thedisplayCustomerInfomethod for both the instances. Forexample:cObject2=cObject1. Assuming thatcObject1andcObject2are the two instances of theCustomerclass.

4. Save, compile and run the program.5. Check the output of thedisplayCustomerInfo methods for both

the objects.


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Exercise 2: Using the StringClass


Exercise 2: Using the StringClass

The objective of this exercise is to create and initializeString objects andto print their contents.

Preparation

Ensure that thePersonTwoTest.javafile exists in theSL110/exercises/05_objects/exercise2directory. This is yourworking directory.

Task Creating and UsingStringObjects

In this task, you write a class calledPersonTwo that creates and initializestwoStringvariables and displays their values. Follow these steps tocreate your class:

1. Go to the working directory.

2. Create a class calledPersonTwothat creates and initializes twovariables:

The first variable stores a quotation.

The second variable stores the name of the person who said thequotation.

3. Use a method calleddisplayQuote to display the quotation and thename of the person to the screen.

4. Compile your class.

5. Execute your class using the providedPersonTwoTestclass.


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Exercise 3: Using the Java SE API Specification


Exercise 3: Using the Java SE API Specification

The objective of this exercise is to allow you to become familiar with theJava SE API specification.

Task Examining the Java SE API Specification

Note The intent of this exercise is to become familiar with thedocumentation and how you look up classes and methods. You are notexpected to understand everything you look at. As you progress throughthis course, the Java API documentation should make more sense.

To view the Java API 6.0 specification:

1. Go to the following URL:

http://java.sun.com/javase/6/docs/

2. From the site listed, find the API specification.

3. Using the API specification, complete the following:

a. Find theMathclass under thejava.langpackage. How manymethods are there in this class?

b. What class does every class refer to at the top of the page?Hint: What class is the superclass to all classes?

4. Find theStringclass. Identify the methods ofStringclass, whichwill enable you to compare two strings.


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Exercise Summary


Exercise Summary

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!


Experiences

Interpretations

Conclusions

Applications


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Lab 6

UsingOperatorsand DecisionConstructs

Objectives



Useifandif/elseconstructs in a Java program

Useswitchconstruct in a Java program


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Lab Overview


Lab Overview


In the first exercise, you create if and if/else constructs.

In the second exercise, you createswitchconstructs


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Using Operators and Decision Constructs 6-3Copyright2007 SunMicrosystems, Inc. AllRightsReserved. SunServices,RevisionE.1



1. What is the purpose of the else block in an if-else statement?

a. To contain the remainder of the code for a method.

b. To contain code that is executed when the expression in anifstatement isfalse.

c. To test whether an expression isfalse.

2. Which of the following sentences is suitable for testing a value in aswitchconstruct?

a. Theswitchconstruct tests whether values are greater than orless than a single value.

b. Theswitchconstruct tests against a single variable.c. Theswitchconstruct tests the value of a float, double, or

boolean data type.

3. What relational operators and conditional operators are mentionedin the following paragraph?If the time is 8:00 a.m., then it is time for work and time for coffee. Ifthe time is greater than 12:00 p.m., it is time for lunch or time for tea.If the time is 5:00 p.m. or later, it is time to go home.

a. ==,>,=>

b. ==,&&,

d. ==,||,>


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4. Read the following code snippet and identify the correct options:1 String clothing1;2 String clothing2;3 clothing1 = "socks";

4 clothing2 = "pants";

5 if (clothing1 == clothing2)a. Line 5 tests if the String literals pointed to by theclothing1

andclothing2references are equal

b. Line 5 tests the String objects' references in memory, not theircontents.

c. By replacing Line 5 with theif (clothing1.equals(clothing2)) statement, the stringliterals referenced byclothing1andclothing2are equal.

d. Line 5 always returnstrue


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Exercise 1: Usingifand if/elseConstructs


Exercise 1: Using ifand if/elseConstructs

The objective of this exercise is to create classes that useifandif/elseconstructs.

Preparation

Ensure thatDateTwoTest.javaandClockTest.javafiles exists in theSL110/exercises/06_decision/exercise1directory. This is yourworking directory.

This exercise has two tasks. In each task you create a class and use theif/else statements where ever applicable. The tasks are:

Task 1 Writing a Class That Usesif/elseStatements Task 2 Writing Another Class That Usesif/elseStatements

Task 1 Writing a Class That Usesif/elseStatements

In this task, you write a class calledDateTwothat usesif/elsestatements to display the day of the week based on the value of a variable.Follow these steps to write your class:

1. Go to your working directory. Create a class calledDateTwowithone member variable calleddayNumber. Assign a value todayNumber between 1 and 7 where:

The number 1 represents Monday (beginning of the week).

The number 7 represents Sunday (end of the week).

2. In theDateTwo class, create adisplayDaymethod that usesif/elseconstructs to inspect the value of the dayNumber and displays thecorresponding day of the week. ThedisplayDaymethod shouldalso display an error message if an invalid number is found.

3. Save, compile, and execute your class using the providedDateTwoTestclass file.

4. Repeat Step 3 several times by assigning different values to theDateTwomember variabledayNumber in theDateTwoTest.java file.


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Exercise1: Using ifand if/elseConstructs


Task 2 Writing Another Class That Usesif/elseStatements

In this task, you write a class calledClockthat usesif/elsestatements

to display the part of day depending on the time of day. Use the followingtable as a guideline.

Follow these steps to write your class:

1. Go to your working directory.

2. Create a class calledClockwith a variable calledcurrentTimethatcontains the hour of day.

3. In theClockclass, create adisplayPartOfDaymethod that usesif/else constructs to display the part of the day associated with thevalue of thecurrentTimevariable. For example, if the value of thecurrentTime variable is equal to 1504, your program would display

Afternoon.

4. Compile and execute your program using theClockTestclass file.

5. Repeat Step 4 several times by assigning different values to the Clockmember variablecurrentTimein theClockTest.javafile.

Note A leading zero indicates an octal value. Therefore, the programdoes not compile if you setcurrentTimeto 0800. You need to specifycurrentTime as 800 for 8:00 AM to successfully compile the program. Notests have been done for values that lie outside the range of 100 and 2400.

Time of Day Part of Day

8:01 to 12:00 Morning

12:01 to 17:00 Afternoon

17:01 to 24:00 Evening

0:01 to 8:00 Early Morning


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Exercise 2: Using the SwitchStatement


Exercise 2: Using the SwitchStatement

The objective of this exercise is to practice using theswitchconstruct indecision-making programs. In this exercise, you create a program thatdisplays the name of the month based on the month number.

Preparation

Ensure that theMonthTest.java file exists in theSL110/exercises/06_decision/exercise2directory. The is yourworking directory.

Task Writing a class That Uses theswitchStatement

In this task you create a class calledMonththat uses switch statements todisplay the name of the month based on the numeric value of a variable.

Complete the following steps

1. In your working directory, create a class calledMonthand save thefile asMonth.java.

2. In theMonthclass, create a variable calledmonthNumber. Assign avalue to the variable that is between 1 and 12, where the number 1

represents the month of January and the number 12 represents themonth of December.

3. In theMonthclass, create adisplayMonthmethod that uses aswitchconstruct to inspect the value of themonthNumbervariableand displays the corresponding name of the month. ThedisplayMonthmethod should also display an error message if aninvalid number is used.

4. Save and compile the file.

5. Execute the program by running the MonthTest class file.

6. Repeat Step 5 several times assigning different values to the Monthmember variablemonthNumberin theMonthTest.javafile.


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Exercise Summary


Exercise Summary

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Experiences

Interpretations

Conclusions

Applications


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Lab 7

UsingLoopConstructs

Objectives



Usewhileanddo/whileloops in a Java program

Useforloops in a Java program


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Lab Overview


Lab Overview

In this lab, you complete the review questions and three exercises.

In the first exercise, you createwhileloop constructs.

In the second exercise, you createforloop constructs.

In the third exercise, you createdo/whileloop constructs.


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Using Loop Constructs 7-3Copyright2007 SunMicrosystems, Inc. AllRightsReserved. SunServices,RevisionE.1



1. Fill in the blank of the following sentence with one of the options

given below. ________________ enables you to check and recheck adecision to execute and re-execute a block of code.

a. Classes

b. Objects

c. Loops

d. Methods

2. Which type of loop allows you to declare a variable as part of itsconstruct:

a. Thedo/whileloopb. Thewhileloop

c. The nestedwhileloop

d. Theforloop

3. Which of the following types of loops is a one/many iterative loop:

a. Thewhileloop

b. The nestedwhileloop

c. Thedo/whileloop

d. Theforloop

4. State whether the following statement is true or false:You should prefer to use the for loop to step through statements apre-defined number of times.


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Exercise 1: Using the whileLoop



The objective of this exercise is to create classes that usewhileloopconstructs.

Preparation

Ensure thatCounterTest.java file andSequenceTest.java file exists intheSL110/exercises/07_loops/exercise1directory. This is yourworking directory.

This exercise has two tasks. In each task you create a class and use thewhile loops wherever applicable. The tasks are:

Task 1 Writing a Class That Uses awhileLoop Task 2 Writing Another Class That Uses awhileLoop

Task 1 Writing a Class That Uses awhile Loop

In this task, you write a class calledCounterand use awhileloop todisplay the value of a count variable that is incremental in steps of one.Follow these steps to create your class:

1. Open the terminal window and go to your working directory. Using

an editor, create a class calledCounterwith three member variablescalledMAX_COUNT,step, andcount. Assign the value 50 toMAX_COUNTand the value 1 to count andstep.Ensure thatMAX_COUNTis declared as afinalvariable.

2. Create apublic displayCountmethod in the class that does notaccept any argument and returnsvoid. For example:public void displayCount(){

3. Create awhile loop in the method with the following characteristics:

a. Boolean expression: Repeat if the value ofcountis less than or

equal to the value ofMAX_COUNTb. Code block:

Print the value of the count variable

Increment the value of count by step value. For example:count=count + step;

4. Save and compile theCounter.javafile.


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5. Compile theCounterTest.javafile that is provided in yourworking directory. Execute theCounterTestclass file.

6. Verify if your class prints all the numbers between 1 and 50.

7. You can modify the value of thestepvariable to modify the output

of theCounter

class. Perform the following steps:a. Open theCounterTest.javafile for modification.

b. Before thedisplayCountmethod is invoked, assign a value of2 to thestepmember variable of the Counter class. Use theobject of theCounterclass to access thestepmember variable.

c. Complete steps 3 - 4 and verify the output. The output shouldbe: 1 3 5 7.............49

8. Repeat Step 6, for thestepvalue of 3.stepis the member variableofCounterclass.

Task 2 Writing Another Class That Uses awhileLoop

In this task, you write a class namedSequence1that displays a sequencestarting with the numbers 0 and 1. Successive numbers in the sequenceare the sum of the previous two numbers. For example: 0 1 1 2 3 5 8 1321...... This sequence is also called the Fibonacci series.

Follow these steps to write your class:1. Go to your working directory and open an editor.

2. Create a class calledSequence1with three variables calledfirstNumber, secondNumber, andnextNumber. Assign the values of 0and 1 to the firstNumberand secondNumbervariables, respectively.

3. Create apublicmethod calleddisplaySequencewith no returntype and no argument, that will perform the following actions:

a. Print the value of firstNumber, secondNumberto start with thesequence.

b. Calculate the sum offirstNumberandsecondNumberandassign the sum to thenextNumbervariable.


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4. Create awhile loop in the method with the following characteristics:

Boolean expression: Repeat if the value ofnextNumber is less thanor equal to 100

Code block:

Print the value of thenextNumbervariable. Assign the value ofsecondNumber to firstNumberand the

value ofnextNumbertosecondNumbervariables.

Recalculate the value ofnextNumberto be the sum offirstNumber andsecondNumber.

5. Save and compile theSequence1.javafile.

6. Compile theSequenceTest.java file provided in your workingdirectory and execute theSequenceTestclass file.

7. Verify the output. The result should look like: 0 1 1 2 3 5 8 13 21 34 55

89


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Exercise 2: Using the for loop



The objective of this exercise is to use theforloop in a class.

Preparation

Ensure that theCounterTwoTest.java file and theSequence2Test.javafile exist in theSL110/exercises/07_loops/exercise2directory. This is your workingdirectory.

This exercise has two tasks. In each task you create a class and use the forloop where ever applicable.

Task 1 Writing a Class That Uses theforLoop Task 2 Modifying awhileLoop to aforLoop

Task 1 Writing a Class That Uses thefor Loop

In this task, you write a class that counts from 1 to a constant number anddisplays all the numbers divisible by 12 between them.

Complete the following steps to write your class:

1. Go to the working directory and open an editor.

2. Write a class calledCounterTwo containing a member variable calledMAX_COUNT. Assign the values of 100 to the variable.

3. Create apublicmethod calleddisplayCountwith no argumentand no return type, which:

Counts from 1 to the value of theMAX_COUNTconstant, using aforloop. Increment the value of the loop variable by 1.

Displays the value of the loop variable if it is divisible by 12.

4. Save your class asCounterTwo.javafile and compile the class.5. CompileCounterTwoTest.java file and execute it to verify the

output. The result should look like: 12 24 36 48 60 72 84 96


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Task 2 Modifying awhile Loop to afor Loop

In this task, you modify the class that you created in Exercise 1, Task 2and replace thewhileloop with aforloop.


1. Create a classSequence2similar toSequence1as in Exercise 1,Task 2 and save it asSequence2.javain your working directory.

2. Create an additional final member variable,SEQUENCE_COUNT, andassign 10 to it. Ensure that the other member variables remainunchanged.

3. In thedisplaySequencemethod, modify thewhileloop to aforloop such that only the first 10 values of the fibonacci series aredisplayed. The result should look like: 0 1 1 2 3 5 8 13 21 34.

4. Save and compile theSequence2.javafile.

5. Compile the providedSequence2Test.java, execute it, and verifythe output.


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Exercise 3: Using the do/whileLoop


Exercise 3: Using the do/whileLoop

The objective of this exercise is to write a class that uses ado/whileloop.

Preparation

Ensure that theDiceTest.java file exists in theSL110/exercises/07_loops/exercise3directory. This directory isyour working directory.

Task Writing a Class Using thedo/while Loop

In this task, you write a class that simulates a simple game of throwing

two dice. Follow these steps to write your class:

1. Go to the working directory.

2. Write a class calledDicecontaining two member variablesdiceNumber1anddiceNumber2to hold the dice numbers.

3. Create apublicmethod calledthrowDicewith no argument and noreturn type and add ado/whileloop with the followingcharacteristics:

Code block: Generate a random number between 1 and 6 andassign it todiceNumber1variable. Repeat the same fordiceNumber2variable. For example:diceNumber1=(int)(Math.random()*6) +1;Print the value ofdiceNumber1 anddiceNumber2 variables.

Boolean expression: Repeat ifdiceNumber1is equal todiceNumber2.

4. Save and compile theDiceclass.

5. Use theDiceTest.javafile to test the result of theDiceclass.

6. Verify that the values ofdiceNumber1anddiceNumber2aredisplayed.


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Exercise Summary


Exercise Summary

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Experiences

Interpretations

Conclusions

Applications


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Lab 8

Developing and Using Methods

Objectives



Create methods and use the methods in a Java program

Use method overloading in a Java program


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Lab Overview


Lab Overview


In the first exercise, you create methods and invoke them.

In the second exercise, you create overloaded methods and use them.


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Developing and Using Methods 8-3Copyright2007 SunMicrosystems, Inc. AllRightsReserved. SunServices,RevisionE.1



1. State which of the following statements are true:

a. A class can only contain one single method declaration.

b. The most basic form of a method is one that has a return typebut no arguments.

c. All calling methods can be worker methods and all workermethods can be calling methods.

d. Overloaded methods have the same number of arguments.

2. The main method accepts which of the following argument types:

a. AStringobject

b. Aninttype

c. An array of references toStringobjects

d. An array ofStringobjects

3. Which method corresponds to the following method call?

myPerson.printValues (100, 147.7F, "lavender");

a. public void printValues (int pantSize, floatageInYears)

b. public void printValues (pantSize, float

ageInYears, favoriteColor)c. public void printValues (int pantSize, float

ageInYears, String favoriteColor)

d. public void printValues (float ageInYears, StringfavoriteColor, int pantSize)


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Exercise1: Using Arguments and Return Values


Exercise 1: Using Arguments and Return Values

The objective of this exercise is to write a class with a method that invokesa worker method in another class.

In this exercise, you create a small application that instantiates three shirtobjects and applies a different price to each.

Then the application instantiates a purchase receipt object that reports thetotal price as each shirt is added to the order.

Preparation

Ensure that theOrder.javafile andthe Shirt.javafile exists in the

SL110/exercises/08_methods/exercise1directory. This is yourworking directory.

Task Writing a Method That Uses Arguments andReturn Values

In this task, you write a test class that adds multipleShirtobjects to anOrder object and displays a total current amount, in dollars, for the order.Follow these steps to write your test class:


2. Open theShirt.javafile and examine the member variables andthe method in it.

3. Open theOrder.javafile and examine its member variables andmethod in it.

4. Write a new class calledOrderTestcontaining amainmethod.

5. In themainmethod:

a. Create and initialize an object of typeOrderand an object of

typeShirt. TheOrderclass (Order.java) and theShirtclass(Shirt.java) are provided in the exercise1 directory.

b. Declare a variable of type double, name it astotalCostandinitialize it by 0.0.

c. Assign thepricefor theShirtobject to 14.00.


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Exercise1: Using Arguments and Return Values


d. Invoke theaddShirtmethod of theOrderclass using theOrder instance to add theshirt instance to the order. Store thereturn value of theaddShirtmethod in the totalCost variable.The documentation for theaddShirtmethod is as follows:

public double addShirt (Shirt s)

Adds a shirt to a list of shirts in an order

Parameters:

s An object reference to aShirtobject

Returns:

A total current amount for the order

e. Display the return order amount. For example:

Total amount for the order is: 14.00

6. Compile and execute your program. Verify if the total order value isdisplayed.

7. In the main method ofOrderTestclass, create additionalShirtobjects, assign values to theprice variable of the newShirt objects,and add theShirtobjects to your order by invoking theaddShirtmethod.

8. Save and compile theOrderTest.javafile.

9. ExecuteOrderTestclass and verify that the total order value isdisplayed correctly.


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Exercise2: Using Overloaded Methods


Exercise 2: Using Overloaded Methods

The objective of this exercise is to implement method overloading.

In this exercise, you create overloaded methods in a class and invoke themethods and test it.

Preparation

Ensure thatCustomerTest.javafile exists in theSL110/exercises/08_methods/exercise2directory. This is yourworking directory.

Task Developing a Class With an OverloadedMethod

In this task, you write aCustomer class with an overloaded method calledsetCustomerInfo.

Follow these steps to write your class:

1. Go to theworking directory and open an editor.

2. Create a class calledCustomer and save the file asCustomer.java

in the working directory.

3. Within theCustomerclass, add two overloaded methods calledsetCustomerInfo.

Depending on how thesetCustomerInfomethod is called, it doesone of the following:

Sets the ID, name, address, and phone number for aCustomerobject. (This is the minimum information needed for a newCustomer.)

Sets the ID, name, address, phone number, and email address

for aCustomerobject.

4. Create adisplay method to display the values of all the membervariables of theCustomerclass.

5. Save and close theCustomer.javafile.

6. Open the file calledCustomerTest.java to test the overloadedmethods of theCustomerclass.


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Exercise 2: UsingOverloaded Methods


7. In themainmethod ofCustomerTest class write code to perform thefollowing tasks:

a. Create two object references to differentCustomerobjects.

b. Use each variation of thesetCustomerInfo method to provide

information for eachCustomer

object.c. Display the contents of eachCustomerobject.

8. Save and compile the fileCustomerTest.javafile.

9. Execute theCustomerTestclass and view the output of the class.


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Exercise Summary


Exercise Summary

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Experiences

Interpretations

Conclusions

Applications


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Lab 9

ImplementingEncapsulationandConstructors

Objectives


Complete review questions Use encapsulation in a Java technology class

Implement constructors in a class


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Lab Overview


Lab Overview

In this lab, you complete the review questions and three exercises.

In the first exercise, you implement encapsulation in a Java

technology class. In the second exercise, you access encapsulated attributes of a class.

In the third exercise, you implement constructors in a Javatechnology class.


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Implementing Encapsulation and Constructors 9-3Copyright2007 SunMicrosystems, Inc. AllRightsReserved. SunServices,RevisionE.1



1. Which of the following statements defines an interface

a. The way a class completes its tasks within a method

b. The operations and attributes of an object

c. The way other objects interact with an object

d. The declaration of private attributes


a. The private members of an object can be accessed throughpublic methods

b. Constructors cannot be overloaded

3. The scope of a variable refers to:

a. The lifetime of the variable

b. Where a variable can be used within a program, also known as,the extent of a variable.

c. The way other objects interact with an object

d. Whether the variable isprivateorpublic

4. What is the default constructor for the following class?

public class Penny {String name = "lane";

}

a. Penny()

b. public Penny()

c. class()

d. String()


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Exercise 1: Writing Encapsulated Classes



The objective of this exercise is to write a class that uses encapsulation tohide data from other objects.

In this exercise, you create a class calledDateOne and modify its attributesto implement encapsulation and examine the output.

This exercise consists of two tasks:

Task 1 Implementing Encapsulation in a Class

Task 2 Accessing Encapsulated Attributes of a Class

Preparation

Ensure that theDateOneTest.java,DateTwoTest.java, andDateThreeTest.javafiles exists in theSL110/exercises/09_encapconstr/exercise1directory. This is yourworking directory.

Task 1 Implementing Encapsulation in a Class

In this task, you create a class containingprivateattributes and try to

access them in another class.

Follow these steps to write your test class:


2. Create a class calledDateOnethat contains three member variablesof typeintnamed:day,month,and year. Givepublicaccess to allthe member variables. Save the class with the nameDateOne.java.

3. Open theDateOneTest.java file provided in the working directoryand write the following in itsmainmethod:

a. Create and initialize an object of typeDateOne.b. Assign different numeric values to the member variables of the

DateOneinstance.

c. Display the value of the member variables of theDateOneinstance.

4. Save and compileDateOneTest.javafile.


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5. Execute theDateOneTestclass file and examine the output.

6. Create a new class calledDateTwosimilar toDateOnewith threemember variables and save it asDateTwo.java.

7. Modify the access specifier of the three member variables ofDateTwo

toprivate

.8. Open theDateTwoTest.java file provided in the working directory

and perform the same steps as in Step 3. However, in this case createan instance ofDateTwoclass instead ofDateOneclass. The otherlines of code will remain the same.

9. Save and compileDateTwoTest.java.

10. Examine the compilation errors and identify the reason of thecompilation errors.

Task 2 Accessing Encapsulated Attributes of a Class

In this task, you create a class with private attributes and enable them tobe manipulated from another class.


1. Create a class calledDateThreeand save it withDateThree.javafile name.

2. DateThreeclass has the same three private member variables as

DateTwoclass.3. Add the following methods in theDateThreeclass:

a. getandsetmethods for all three member variables. Forexample:

public void setDay(int d) { day = d;

}public int getDay() { return day; }


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b. ThesetDatemethod It accepts three arguments of typeintand assigns the value of the arguments to theday,month, andyearmember variables of theDateThreeclass, respectively.Before assigning the parameters to the member variablesvalidate them such that the day is within 30, 31, 28, 29, and

month is between 1 and 12 and year is between 1000 and 10000.For example February 31 should not be accepted. Errormessages should be displayed whenever the validation fails.

Note Useswitch casestatements andif elsestatements forperforming the validations.

ThedisplayDatemethod Prints the date in the followingform:Todays Date is: 10/25/2006

4. Save and compileDateThree.java

5. Open theDateThreeTest.java file provided in the workingdirectoryand perform the following in themainmethod:

a. Create and initialize and instance ofDateThreeclass

b. Invoke thesetDay,setMonth, andsetYearmethods and passvalid values as arguments to these methods.

c. Display the values of theDateThreemember variables using itsgetDay,getMonth, andgetYearmethods. For example:System.out.println( The date is +dateObj.getMonth()+ / dateObj.getDay() + / +dateObj.getYear());

// dateObj is an instance of DateThree class

6. Save and compile theDateThreeTest.javafile.

7. Execute theDateThreeTestclass and examine the output.

8. Reopen theDateThreeTest.javafile.

9. In themainmethod, add code at the end which will do thefollowing:

a. Invoke thesetDatemethod using the instance ofDateThree

class and pass valid values as arguments to the method.

b. Invoke thedisplayDatemethod using the instance ofDateThreeclass.


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10. Save, compile, and execute theDateThreeTest.javafile.

11. Examine the output and see if any error messages are displayed.

12. In theDateThreeTest.java file, modify the value of the argumentspassed in thesetDatemethod, repeat Step 10 and Step 11.

?

!

Discussion You can discuss the possible error conditions while settingvalues for the month, day, and year in thesetDatemethod. Ask thestudents to test theDateThreeclass with all of them and verify the errormessages.


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Exercise 2: Using Constructors



The objective of this exercise is to implement constructors in a class.

In this exercise, you create overloaded constructors in a class and usethem to initialize objects of that class.

You have two tasks in this exercise:

Task 1 Creating and Using Constructors

Task 2 Creating Constructors to Initialize Objects

Preparation

Ensure that theDateFourTest.java andRectangleTest.java file existsin theSL110/exercises/09_encapconstr/exercise2directory. This isyour working directory.

Task 1 Creating and Using Constructors

In this task, you write aDateFourclass with constructors and createobjects of the class to use the constructors appropriately.

Follow these steps to write your class:1. Go to your working directory and open an editor.

2. Create a class calledDateFour similar toDateThree as in Exercise 1and save the file asDateFour.javain the working directory.

3. Add a constructor, with no arguments, to theDateFour.javafilethat assigns the value ofmonthto 1, theday to 1, and theyear to2007.

4. Rename thesetDatemethod to be a constructor that accepts,verifies, and sets themonth,day, andyear.

5. Save and compile theDateFour.javafile.

6. Open theDateFourTest.javafile. In themainmethod createDateFourobjectsd1andd2, whered1is created using the no-argument constructor andd2is created using the three-argumentconstructor.


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7. In yourDateFourTestclass, invoke thedisplaymethod to displaytheday,month, andyearvalues ford1andd2.

8. Compile theDateFourTest.javafile, execute it, and verify theoutput.

The output from theDateFourTest

class should be similar to thefollowing:

Todays Date is: 1/1/2007Todays Date is: 3/9/1967

Task 2 Creating Constructors to Initialize Objects

In this task, you create a class and use constructors to initialize objects.Follow these steps to create yo

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