advanced java programming cse 7345/5345/ ntu 538n

Liang, Oreilly, Herbert Schildt, Joseph O’Neil

Advanced Java Programming

CSE 7345/5345/ NTU 538NSession 2

Welcome Welcome Back!!!Back!!!


[email protected]@engr.smu.edu

Chantale Laurent-

Rice

Welcome Welcome Back!!!Back!!!

[email protected]@aol.com

Office Hours:by appt3:30pm-4:30pmSIC 353


Introduction

• Chapter 1– Course Objectives– Organization of the Book


Objectives

• Upon completing this chapter, you will understand – Create, compile, and run Java

programs– Primitive data types


Book Chapters• Part I: Fundamentals of Programming

– Chapter 1 Introduction to Java

– Chapter 2 Primitive Data Types and Operations

– Chapter 3 Control Statements

– Chapter 4 Methods

– Chapter 5 Arrays


Book Chapters, cont.• Part II: Object-Oriented Programming

– Chapter 6 Objects and Classes

– Chapter 7 Strings

– Chapter 8 Class Inheritance and Interfaces

– Chapter 9 Object-Oriented Software Development


Book Chapters, cont.

• Part III: GUI Programming

– Chapter 10 Getting Started with GUI Programming

– Chapter 11 Creating User Interfaces

– Chapter 12 Applets and Advanced GUI


Book Chapters, cont.• Part IV: Developing Comprehensive

Projects– Chapter 13 Exception Handling

– Chapter 14 Internationalization

– Chapter 15 Multithreading

– Chapter 16 Multimedia

– Chapter 17 Input and Output

– Chapter 18 Networking

– Chapter 19 Java Data Structures


Chapter 1 • Objectives:• Get an overall perspective of what

capabilities and features are encompassed by Java and its development kit.

• Take a first look at Java syntax.• Getting Input from Input Dialog

Boxes • Style and Documentation

Guidelines


What Is Java?

•History

•Characteristics of Java


What is Java?• An Object-Oriented Programming Language

developed at Sun Microsystems• A Virtual Machine (run-time environment)

that can be embedded in web browsers (e.g. Netscape Navigator, Microsoft Internet Explorer and IBM WebExplorer) and operating systems.

• A set of standardized Class libraries (packages), that support:– Creating graphical user interfaces– Communicating over networks– Controlling multimedia data


History• James Gosling and Sun Microsystems

• Oak

• Java, May 20, 1995, Sun World

• HotJava – The first Java-enabled Web browser

• JDK Evolutions

• J2SE, J2ME, and J2EE (not mentioned in the book)


Characteristics of Java

• Java is simple• Object-Oriented• Distributed• Interpreted• Robust

• Secure• Architecture-

neutral• Portable• High-performance• Multithreaded• dynamic


Java is Simple

• Java is not just a language for use with the Internet.

• It is a full featured Object-Oriented Programming Language (OOPL).

• Java is a bit easier than the popular OOP language C++.

• Java uses automatic memory allocation and garbage collection.


What is Object-Oriented Programming?

• Think of OOP as a set of implementation techniques that– Can be done in any programming

language– Are very difficult to do in most

programming languages– OOP provides great flexibility,

modularity, and reusability.


Java is Distributed

• Distributed computing involves several computers working together on a network.

• Java’s concurrency features make is unique for developing many interactive and networked applications.


Java is Interpreted• Java Virtual Machine:

– Java is compiled to byte-codes whose target architecture is the Java Virtual machine (JVM).

– The virtual machine is embeddable within other environments, e.g. web browser and operating systems.

– Utilize a byte-code verifier when reading in byte-codes. The class loader is employed for “classes” loaded over the network (enhances security)


Java Virtual Machine

• JVM

Java Source code .java

Java byte-code .class

Environment

Java VMjavac java


Java is Robust• Robust means reliable.• No programming language can ensure

complete reliability.• Java puts a lot of emphasis on early

checking for possible errors, because Java compilers can detect many problems that would first show up at execution time in other languages.

• Java has a runtime exception-handling feature to provide programming support for robustness.


Java Is Architecture-Neutral• Java is interpreted.• JIT compiler

– Just-in-time compilers– This provides

•Improved performance•Better match to specific hardware


JIT Compiler

• JIT- takes byte-codes and change it to machine code.

JVMRunning

Applet or Application

J.I.T.Compiler

.class file

machine code


JIT Compiler

• Because of the need for architecture independence, performance tuning must be performed on the client-side.

• This client-side compilation is known as Just-In-Time (JIT) compilation.


Portable, Dynamic, Multithreaded, and Extensible

• Java runtime based on architecturally-neutral byte-codes

(per class).• Multithreading is a program’s capability to perform

several tasks simultaneously.

interpretedJavaRuntime

Native .dll

Native .dll

call

loadedclasses

(byte-codes)

.classfiles


Advantages• Byte-code is a compact machine

language form. In Java the target machine is the Java Virtual Machine (VM).

• These byte-codes are thus portable across architecture boundaries.

• Applets and Applications have “class” files loaded on their behalf in order to execute.


JDK Versions

• JDK 1.02 (1995)• JDK 1.1 (1996)• Java 2 SDK v 1.2 (a.k.a JDK 1.2,

1998)• Java 2 SDK v 1.3 (a.k.a JDK 1.3,

2000)• Java 2 SDK v 1.4 (a.k.a JDK 1.4,

2002)


JDK Editions• Java Standard Edition (J2SE)

– J2SE can be used to develop client-side standalone applications or applets.

• Java Enterprise Edition (J2EE)– J2EE can be used to develop server-side applications

such as Java servlets and Java ServerPages.

• Java Micro Edition (J2ME). – J2ME can be used to develop applications for mobile

devices such as cell phones.

This book uses J2SE to introduce Java programming.


Java IDE Tools

• Forte by Sun MicroSystems • Borland JBuilder

• Microsoft Visual J++

• WebGain Café

• IBM Visual Age for Java

• IBM Eclipse


Getting Started with Java Programming

• A Simple Java Application

• Compiling Programs

• Executing Applications


Command Line Example 1.1//This application program prints Welcome//to Java! package chapter1;

public class Welcome { public static void main(String[] args) { System.out.println("Welcome to Java!"); }}

RunRunSourceSource


Creating and Compiling Programs

• On command line– javac file.java

Source Code

Create/Modify Source Code

Compile Source Code i.e. javac Welcome.java

Bytecode

Run Byteode i.e. java Welcome

Result

If compilation errors

If runtime errors or incorrect result


Executing Applications• On command line

– java classname

JavaInterpreter

on Windows

JavaInterpreter

on Sun Solaris

JavaInterpreteron Linux

Bytecode

...


Command line Example

javac Welcome.java

java Welcome

output:...


Compiling and Running a Program

Where are the files stored in the directory?

c:\example

chapter1 Welcome.class

Welcome.java

chapter2

.

.

.

Java source files and class files for Chapter 2

chapter19 Java source files and class files for Chapter 19

Welcome.java~


There are three forms of comments in Java.

1- int i = 10; // i is used as a counter2- The multiline comment /* This is a comment */

This form of comment may also extend over several lines as shown here:/* This is a longer comment

that extends over five lines.

*/


There are three forms of comments in

Java. 3- This is the documentation comment.

/** This is a Java documentation comment

*/The advantage of documentation comments is that tools can extract them from source files and automatically generate documentation for your programs. The JDK has a tool named javadoc that performs this function.


Package•The second line in the program (package chapter1;) specifies a package name, chapter1, for the class Welcome.

•Forte compiles the source code in Welcome.java, generates Welcome.class, and stores Welcome.class in the chapter1 folder.


Blocks

A pair of braces in a program forms a block that groups components of a program.

public class Test { public static void main(String[] args) { System.out.println("Welcome to Java!"); } }

Class block

Method block


Block Styles

Use end-of-line style for braces.

public class Test { public static void main(String[] args) { System.out.println("Block Styles"); } }

public class Test { public static void main(String[] args) {

System.out.println("Block Styles"); } }

End-of-line style

Next-line style


main MethodThe main method provides the control of program flow. The Java interpreter executes the application by invoking the main method. The main method looks like this: public static void main(String[] args) { // Statements;

}


Displaying Text in a Message Dialog Box

• you can use the showMessageDialog method in the JOptionPane class.

• JOptionPane is one of the many predefined classes in the Java system, which can be reused.

RunRunSourceSource


The showMessageDialog Method

JOptionPane.showMessageDialog(null, "Welcome to Java!", "Example 1.2", JOptionPane.INFORMATION_MESSAGE));


A simple Java Applet

import java.awt.*;import java.awt.event.*;import java.applet.Applet;import java.awt.Graphics;

/*<applet code="FirstApplet" width=200 height=200></applet>

*/

public class FirstApplet extends Applet{

public void paint(Graphics g){ g.drawString("This is my first applet!", 20, 100);}

}See word doc for output.


Integral Literals

• Integral literals may be expressed in decimal, octal, or hexadecimal.

• The default is decimal.• To indicate octal, prefix the literal with 0

(zero)• To indicate hexadecimal, prefix the

literal with 0x or 0X; • the hex digits may be upper-or

lowercase.


Integral Literals For example:

The value twenty-eight may be expressed the following ways:

28 034 0x1c 0x1C 0X1c 0X1C


Integral Literals

• By default, an integral literal is a 32-bit value.

• To indicate a long (64-bit) literal, append the suffix L to the literal expression.

• The suffix can be lowercase, but then it looks so much like a one that makes it confusing.


Literals

• Literals are explicit data values that appear in your program.

• A literal is a value specified in the program source, as opposed to one determined at runtime. Literals can represent primitive or string variables, and may appear on the right side of assignments or in method calls. You cannot assign a value into a literal, so they cannot appear on the left of an assignment.

For example:

int x = 25;


Boolean Literals • The only literals of boolean type

are true and false.

For example: 1. boolean isBig = true; 2. boolean isLittle = false;


char Literals

A char literal can be expressed by enclosing the desired character in single quotes,

For example:

char c = ' w ';


Chapter 1 Topic Summary

• Java is many things– A concurrent object-oriented

programming language– A virtual machine and Web-aware

run-time– A powerful and stable set of class

libraries.


Chapter 2Liang, Nutshell

Objectives:• Introduce Programming with an

Example• Identifiers, Variables, and Constants• Primitive Data Types

– byte, short, int, long, float, double, char, boolean

• Expressions• Operators, Precedence, Associativity,

Operand Evaluation Order: ++, --, *, /, %, +=, -=, *=, /=, %=, ^, &, |, +, -,

• Syntax Errors, Runtime Errors, and Logic Errors


Java Reserved Words or Keywords

• abstract default if private this• boolean do implements protected throw• break double import public throws• byte else instanceof return transient• case extends int short try• catch final interface static void• char finally long strictfpvolatile• class float native super while• const for new switch• continue goto package synchronized


Keyword and identifiers • An identifier is a word used by a

programmer to name a variable, method, class, or label.

• Keywords and reserved words may not be used as identifiers.

• An identifier must begin with a letter, a dollar sign (4), or an underscore (_); subsequent characters may be letter, dollar signs, underscores, or digits.


Examples • foobar // legal

• BIGinterface // legal

• $incomeAfterExpenses // legal

• 3_nodes5 // illegal

• !theCase // illegal


Using Keyword

•Using a keyword as an identifier is a syntax error

•Keywords that are reserved, but not used, by Java–const–goto


Reserved Words•Reserved words or keywords are words that have a specific meaning to the compiler and cannot be used for other purposes in the program.

•For example, when the compiler sees the word class, it understands that the word after class is the name for the class.


Java support eight different basic data

type • Type Description Keyword

• character 16-bit Unicode character data char• boolean true/false values boolean• byte 8-bit signed integer numbers byte• short 16-bit signed integer numbers short• integer32-bit signed integer numbers int• long 64-bit signed integer numbers long• float 32-bit signed floating-point numbers float• double 64-bit signed floating-point numbers double


Primitive Data Type • Java's Primitive C++ Simple data type

data type integral floating

boolean char float char short long byte int long

double short long int enum long unsigned char float unsigned short double unsigned int

unsigned long


Primitive Data Types and Operations

• Type Precision Default Valuebyte 8 bits 0short 16 bits 0

int* 32 bits 0long 64 bits 0char 16 bits \u0000float 32 bits +0.0fdouble 64 bits +0.0dboolean - false‘obj-ref’ - null


The four signed data types are:

byte short int long


Valid Control Character• Valid control character are:

– \b backspace– \t horizontal tab– \n linefeed– \f formfeed– \r carriage return– \” double quote– \’ single quote– \\ backslash– “dddd” for Unicode - is 0000 to hex ffff


Operator Precedence• var++, var--• +, - (Unary plus and minus), ++var,--var• (type) Casting• ! (Not)• *, /, % (Multiplication, division, and modulus)• +, - (Binary addition and subtraction)• <, <=, >, >= (Comparison or Relational)• ==, !=; (Equality) • & (Unconditional AND)• ^ (Exclusive OR) • | (Unconditional OR) • && (Conditional AND) Short-circuit AND• || (Conditional OR) Short-circuit OR• =, +=, -=, *=, /=, %= (Assignment operator)


Bitwise OperatorsJava defines several bitwise

operators which can be applied to the integer types,

long, int, short, char, byte

These operators act upon the individual bits of their operands.


Bitwise OperatorsOperator Name ~ Bitwise unary NOT & Bitwise AND

| Bitwise OR ^ Bitwise exclusive OR >> Shift right >>> Shift right zero fill << Shift left


Bitwise Operators

Operator Name

&= Bitwise AND assignment |= Bitwise OR assignment

^= Bitwise exclusive OR assignment >>= Shift right assignment >>>= Shift right zero fill assignment <<= Shift left assignment


Bitwise NOT ( ~)• Also called the bitwise complement, the

unary NOT operator, ~ , • Inverts all the bits of its operand.

• Example Number 74 before bitwise NOT -> 01001010 after the NOT operator applied -> 10110101


Bitwise AND ( & )• Produces a 1 bit if both operands are

also 1, otherwise a zero is produced. Example Number 74 & 29 -> 8

-> 0 1 0 0 1 0 1 0 -> & 0 0 0 1 1 1 0 1

After -> 0 0 0 0 1 000


Bitwise OR ( | )• Combines bits such that if either of the

bits in the operands is a 1, then the resultant bit is a 1. A zero if both bits are zeros.

Example Number 74 | 29 -> 95

-> 0 1 0 0 1 0 1 0 -> | 0 0 0 1 1 1 0 1

After -> 0 1 0 1 1 1 1 1


Bitwise XOR ( ^ )• Combines bits such that if exactly one

operand is 1, then the result is 1. Otherwise, the result is zero.

Example Number 74 | 29 -> 87

-> 0 1 0 0 1 0 1 0 -> ^ 0 0 0 1 1 1 0 1

After -> 0 1 0 1 0 1 1 1


Left shift ( << )Right shift ( >> )

unsigned right shift ( >>>)• Left shift (>>) shifts all of the bits in a value

to the left a specified number of times.• Right shift (>>) shifts all of the bits in a value

to the right a specified number of times.• Unsigned right shift (>>>) automatically fills

the high-order bits with its previous contents each time a shift occurs. This preserves the sign of the value.


Relational or Comparisons Operators

Operator Name== Equal to!= Not equal to> Greater than< Less than>= Greater than or equal to<= Less than or equal to


Relational OperatorsThe relational operators determine

the relationship that one operand has to the other

They determine equality and ordering.

The result of these operations is a boolean value.


Boolean Logical OperatorsOperator Name

& Logical AND| Logical OR^ Logical XOR (exclusive OR)|| Short-circuit OR&& Short-circuit AND! Logical unary NOT (inverts)


Boolean Logical OperatorsOperator Name

&= AND assignment|= OR assignment^= XOR assignment== Equal to!= Not equal to?: Ternary if-then-else


Boolean Logical OperatorsThe Boolean Logical operators

operate only on boolean operands.

All of the binary logical operators combine two boolean values to form a resultant boolean value.


The boolean Type and Operators

boolean lightsOn = true;

boolean lightsOn = false;

boolean b = (1 > 2);

&& (and) (1 < x) && (x < 100)• || (or) (lightsOn) || (isDayTime)• ! (not) !(isStopped)


Truth Table for Operator !Truth Table for Operator !

Operand !Operand

true false

false true


Truth Table for Operator &&

Operand1Operand2Operand1 && Operand2

false false false

false true false

true false false

true true true


Truth Table for Operator ||Operand1 Operand2 Operand1 || Operand2

false false false

false true true

true false true

true true true


Truth Table for Operator ^

Operand1 Operand2 Operand1 ^ Operand2

false false false

false true true

true false true

true true false


The & and | Operators&&: conditional AND operator&: unconditional AND operator||: conditional OR operator|: unconditional OR operator

exp1 && exp2(1 < x) && (x < 100)

(1 < x) & (x < 100)


The & and | OperatorsIf x is 1, what is x after this expression?

(x > 1) & (x++ < 10)

If x is 1, what is x after this expression?

(1 > x) && ( 1 > x++)

How about (1 == x) | (10 > x++)?

(1 == x) || (10 > x++)?


Getting Input from Input Dialog Boxes

String string = JOptionPane.showInputDialog( null, “Prompt Message”, “Dialog Title”, JOptionPane.QUESTION_MESSAGE));where x is a string for the prompting message and y is a string for the title of the input dialog box.


Convertting Strings to Doubles

To convert a string into a double value, you can use the static parseDouble method in the Double class as follows: double doubleValue =Double.parseDouble(doubleString); where doubleString is a numeric string such as “123.45”.


Read / Work With (Course Links)

• Liang, Nutshell Chapter 3-4• Life Cycle of Applets• List Of Basic Tags• Try It Editor


Chapter 3 Control Statements

•Selection Statements–Using if and if...else–Nested if Statements–Using switch Statements–Conditional Operator

•Repetition Statements–Looping: while, do-while, and for–Nested loops–Using break and continue


Selection Statements

• if Statements

• switch Statements

• Conditional Operators


CautionAdding a semicolon at the end of an if clause is a common mistake.if (radius >= 0);

{

area = radius*radius*PI;

System.out.println(

"The area for the circle of radius " +

radius + " is " + area);

}

This mistake is hard to find, because it is not a compilation error or a runtime error, it is a logic error.

Wrong


switch Statementsswitch (year) { case 7: annualInterestRate = 7.25; break; case 15: annualInterestRate = 8.50; break; case 30: annualInterestRate = 9.0; break; default: System.out.println( "Wrong number of years, enter 7, 15, or 30");}


Repetitions

• while Loops

• do-while Loops• for Loops

• break and continue


Chapter 4 Methods• Introducing Methods

– Benefits of methods, Declaring Methods, and Calling Methods

• Passing Parameters– Pass by Value

• Overloading Methods– Ambiguous Invocation

• Scope of Local Variables

• Method Abstraction

• The Math Class


Introducing MethodsMethod Structure

A method is a collection of statements that are grouped together to perform an operation.


Methods• A method is essentially a set of program

statements. It forms the fundamental unit of execution in Java. Each method exists as part of a class.During the execution of a program, methods may invoke other methods in the same or a different class. No program code can exist outside a method, and no method can exist outside a class.


Using Methods For example:

public class TheMethod{

public static void main(String[] args){

System.out.println(“First method”);}

}


All methods are passed by value.

• All methods are passed by value. This means that copies of the arguments are provided to a method.

• Any changes to those copies are not

visible outside the method.

• This situation changes when an array or object is passed as an argument.


call-by-value argument passing

• In this case the entire array or object is not actually copied.

• Instead, only a copy of the reference is provided.

• Therefore, any changes to the array or object are visible outside the method.

• However, the reference itself is passed by value.



• Method a( ) accepts three arguments:

• an int• an int array• an object reference

The value of these arguments are displayed before and after the method call.



• The key points to note are:

• The change to the first argument is not visible to the main( ) method.

• The changes to the array and object are visible to the main( ) method.


Example:public class CallByValue{


// Initializes variablesint i = 5;int j[] = { 1, 2, 3, 4, };StringBuffer sb = new StringBuffer("abcd");

// Display variablesdisplay(i, j, sb);

// call methoda(i, j, sb);

//Display variables againdisplay(i, j, sb);

}


Example (con’t)public static void a(int i, int j[], StringBuffer sb){

i = 7;j[0] =11;sb.append("fghi");

}public static void display(int i, int j[], StringBuffer sb){

System.out.println(i);for (int index = 0; index < j.length; index++)

System.out.print(j[index] + " ");System.out.println(" ");System.out.println(sb);

}}


Methods that return Values.

The return type for a method can be used in the Java

• The return type for a method can be

any type used in the Java programming language, which includes the primitive (or scalar) types int, double, char, and so on, as well as class type (including class types you create).


Methods that return valuespublic class GettingARaise{


double mySalary = 200.00;

System.out.println("Demonstrating some raises");

predictRaise(mySalary);System.out.println("Demonstrating my salary " +

mySalary);predictRaise(400.00);predictRaiseGivenIncrease(600, 800);

}


Methods that return values public static void predictRaise(double moneyAmount) {

double newAmount;newAmount = moneyAmount * 1.10;System.out.println("With raise salary is " +

newAmount);}

public static void predictRaiseGivenIncrease(double moneyAmount, double percentRate){

double newAmount;newAmount = moneyAmount * (1 + percentRate);System.out.println("With raise predicted given salary is

" + newAmount);}

}


Read / Work With (Course Links)

• Liang, Nutshell Chapter 4-6• Life Cycle of Applets• List Of Basic Tags• Try It Editor

advanced java programming cse 7345/5345/ ntu 538n

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