Java J2EE Sjbit 10is753 Notes

J a v a a nd J 2 E E 1 0 I S 7 5 3

JAVA AND J2EE

Scheme and Syllabus

I.A. Marks : 25 Exam Hours: 03 Exam Marks: 100

PART - A

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Subject Code: 10IS753 Hours/Week : 04 Total Hours : 52

UN IT - 1

UN IT - 2

6 Hours

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INTRODUCTION TO JAVA: Java and Java applications; Java Development Kit (JDK); Java is interpreted, Byte Code, JVM; Object-oriented programming; Simple Java programs. Data types and other tokens: Boolean variables, int, long, char, operators, arrays, white spaces, literals, assigning values; Creating and destroying objects; Access specifiers. Operators and Expressions: Arithmetic Operators, Bitwise operators, Relational operators, The Assignment Operator, The? Operator; Operator Precedence; Logical expression; Type casting; Strings Control Statements: Selection statements, iteration statements, Jump Statements.

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CLASSES, INHERITANCE, EXCEPTIONS, APPLETS: Classes: Classes in Java; Declaring a class; Class name; Super classes; Constructors; Creating instances of class; Inner classes. Inheritance: Simple, multiple, and multilevel inheritance; Overriding, overloading. Exception handling: Exception handling in Java. The Applet Class: Two types of Applets; Applet basics; Applet Architecture; An Applet skeleton; Simple Applet display methods; Requesting repainting; Using the Status Window; The HTML APPLET tag; Passing parameters to Applets; getDocumentbase() and getCodebase(); ApletContext and showDocument(); The AudioClip Interface; The AppletStub Interface; Output to the Console. 6 Hours

UN IT - 3

MULTI THREADED PROGRAMMING, EVENT HANDLING: Multi Threaded Programming: What are threads? How to make the classes threadable; Extending threads; Implementing runnable; Synchronization; Changing state of the thread; Bounded buffer problems, read-write problem, producer-consumer problems. Event Handling: Two event handling mechanisms; The delegation event model; Event classes; Sources of events; Event listener interfaces; Using the delegation event model; Adapter classes; Inner classes. 7 Hours Dept. of ISE, SJBIT Page 1

J a v a a nd J 2 E E 1 0 I S 7 5 3 UN IT - 4

7 Hours

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SWINGS: Swings: The origins of Swing; Two key Swing features; Components and Containers; The Swing Packages; A simple Swing Application; Create a Swing Applet; Jlabel and ImageIcon; JTextField;The Swing Buttons; JTabbedpane; JScrollPane; JList; JComboBox; JTable.

P AR T - B UN IT - 5

UN IT - 6

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JAVA 2 ENTERPRISE EDITION OVERVIEW, DATABASE ACCESS: Overview of J2EE and J2SE. The Concept of JDBC; JDBC Driver Types; JDBC Packages; A Brief Overview of the JDBC process; Database Connection; Associating the JDBC/ODBC Bridge with the Database; Statement Objects; ResultSet; Transaction Processing; Metadata, Data types; Exceptions. 6 Hours

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SERVLETS: Background; The Life Cycle of a Servlet; Using Tomcat for Servlet Development; A simple Servlet; The Servlet API; The Javax.servlet Package; Reading Servlet Parameter; The Javax.servlet.http package; Handling HTTP Requests and Responses; Using Cookies; Session Tracking. 7 Hours

UN IT - 7

JSP, RMI: Java Server Pages (JSP): JSP, JSP Tags, Tomcat, Request String, User Sessions, Cookies, Session Objects. Java Remote Method Invocation: Remote Method Invocation concept; Server side, Client side. 6 Hours

UN IT - 8

ENTERPRISE JAVA BEANS: Enterprise java Beans; Deployment Descriptors; Session Java Bean, Entity Java Bean; Message-Driven Bean; The JAR File. 7 Hours

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J a v a a nd J 2 E E 1 0 I S 7 5 3 T E X T B O O K S:

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1. Java - The Complete Reference – Herbert Schildt, 7th Edition, Tata McGraw Hill, 2007. 2. J2EE - The Complete Reference – Jim Keogh, Tata McGraw Hill, 2007.

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R EF E R E N C E B O O K S: 1. Introduction to JAVA Programming – Y. Daniel Liang, 6th Edition, Pearson Education, 2007. 2. The J2EE Tutorial – Stephanie Bodoff et al, 2nd Edition, Pearson Education, 2004.

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UNIT No.

Page No.

INTRODUCTION TO JAVA Java and Java applications; Java Development Kit (JDK); Java is interpreted, Byte Code. JVM , Object-oriented programming; Simple Java programs Data types and other tokens: Boolean variables, int, long, char, operators, arrays, white spaces, literals, Assigning values ,Creating and destroying objects; Access specifiers. operators and Expressions: Arithmetic Operators, Bitwise operators, Relational operators, The Assignment Operator, The ? Operator; Operator Precedence; Logical expression; Type casting; Strings , Control Statements: Selection statements, iteration statements, Jump Statements CLASSES, INHERITANCE, EXCEPTIONS, APPLETS Classes: Classes in Java; Declaring a class; Class name; Super classes; Constructors; Creating instances of class; Inner classes Inheritance: Simple, multiple, and multilevel inheritance; Overriding, overloading. Exception handling: Exception handling in Java.

1-12 1 1 3

The Applet Class: Two types of Applets; Applet basics; Applet Architecture; An Applet skeleton; Simple Applet display method Requesting repainting; Using the Status Window; The HTML APPLET tag; Passing parameters to Applets; getDocumentbase() and getCodebase() ApletContext and showDocument(); The AudioClip Interface; The AppletStub Interface; Output to the Console. MULTI THREADED PROGRAMMING, EVENT HANDLING Multi Threaded Programming: What are threads? How to make the classes threadable; Extending threads; Implementing runnable; Synchronization; Changing state of the thread; Bounded buffer problems Read-write problem, producer-consumer problems

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1

Index Sheet

4

4 4 6

13-28 13 15 18 20

22 23 29-41 29 30 33

Two event handling mechanisms

35

The delegation event model; Event classes; Sources of events

36

Event listener interfaces; Using the delegation event model

37

Adapter classes; Inner classes

39

SWINGS Swings: The origins of Swing; Two key Swing features

42-49 42

Components and Containers

42

The Swing Packages; A simple Swing Application

45

Create a Swing Applet

46

Jlabel and ImageIcon

47

5

JTextField;The Swing Buttons; JTabbedpane

48

JScrollPane; JList; JComboBox; JTable

49

JAVA 2 ENTERPRISE DATABASE ACCESS:

EDITION

OVERVIEW,

Overview of J2EE and J2SE.

50 50

A Brief Overview of the JDBC process; Database Connection;

50

Associating the JDBC/ODBC Bridge with the Database;

51

Statement Objects ,ResultSet;

52

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The Concept of JDBC; JDBC Driver Types; JDBC Packages

Transaction Processing Metadata,. Data types; Exceptions. SERVLETS

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6

Background

The Life Cycle of a Servlet; Using Tomcat for Servlet Development; A simple Servlet The Servlet API; The Javax.servlet Package

54-60 54 54 55

Handling HTTP Requests and Responses

57

Using Cookies

58

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56

59

JSP, RMI Java Server Pages (JSP): JSP, JSP Tags

61-65

Tomcat, Request String, User Sessions

62

Cookies, Session Objects

64

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Java Remote Method Invocation: Remote Method Invocation concept Server side

8

53

Reading Servlet Parameter; The Javax.servlet.http package

Session Tracking.

7

50-53

61

64 65

Client side.

65

K SI M C

65

D i c s i n g l e w i n do w s a g e n c y S I S I , N S I C , S I D B I , K S F C

65

ENTERPRISE JAVA BEANS Enterprise java Beans;

Deployment Descriptors

66-68 66 67

Session Java Bean

67

Entity Java Bean;

67

Message-Driven Bean, The JAR File.

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J a v a a n d J 2 E E 1 0 I S 7 5 3

UNIT-1 INTRODUCTION TO JAVA

1. Introduction to Java • Java is an object-oriented programming language developed by Sun Microsystems, a company best known for its high-end Unix workstations.

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• Java is modeled after C++

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• Java language was designed to be small, simple, and portable across platforms and operating systems, both at the source and at the binary level (more about this later). • Java also provides for portable programming with applets. Applets appear in a Web page much in the same way as images do, but unlike images, applets are dynamic and interactive.

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• Applets can be used to create animations, figures, or areas that can respond to input from the reader, games, or other interactive effects on the same Web pages among the text and graphics. 1.1 Java Is Platform-Independent

Platform-independence is a program's capability of moving easily from one computer system to another.

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• Platform independence is one of the most significant advantages that Java has over other programming languages, particularly for systems that need to work on many different platforms. •

Java is platform-independent at both the source and the binary level.

1.2 Java Development Kit (JDK)- Byte code • Bytecodes are a set of instructions that look a lot like machine code, but are not specific to any one processor • Platform-independence doesn't stop at the source level, however. Java binary files are also platform-independent and can run on multiple platforms without the need to recompile the source. Java binary files are actually in a form called bytecodes. 1.3 Object-Oriented Programming

• Many of Java's object-oriented concepts are inherited from C++, the language on which it is based, but it borrows many concepts from other object-oriented languages as well.

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• Java includes a set of class libraries that provide basic data types, system input and output capabilities, and other utility functions.

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• These basic classes are pa rt of the Java development kit, which also has classes to support networking, common Internet protocols, and us er interface toolkit fu n c t ion s . • Because these c lass l ibraries a re written in Java, they are port able ac ross platforms as all Ja va applicati ons are.

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1.4 Creating a simple Java Program Hello W orld example : class HelloW orld { public static void main (String args[]) { System.out. println ("Hello W orld! "); } }

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This program has two main pa rts:

• All the program is enclosed in a c lass de fini tion—here, a class called Hello W orld. • Th e body of the progra m (here, just the one line) is contained in a method (function) called main(). In Java applications, as in a C or C++ program, main() is the first meth od (function) that is run when the program is executed.

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1.5 Compiling the above program : •

In Sun 's JDK, the Java compi ler is called javac.

j a v a c H e l l o Wor l d . j ava

• When the program compiles without e rrors , a file called Hell oW orld.class is cre ated, in the same direct ory as the source f ile. This is the Java bytecode fil e. • Then run that bytecode file using the Java interpreter. In the JDK, the Java interpreter is call ed simply java. java HelloW orld

If the program was typed and compiled correctly, the output will be : "Hello W orld!"

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2. V a r i a b l e s a n d D a t a Ty p e s

• Va riables are locations in memory in which values can be stored. The y have a na me, a type, and a value.

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• Java has three kinds of variables: instance variables, class variables, and local variables. • Instance variables, are used to de fine attributes or the state for a pa rticular obje c t . Class variables are similar to in stance varia bl es, except thei r values apply to all that class's instances (and to the class itsel f) rather than h aving different values for each object.

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• Local variables are decl a red and used inside method definitions, for example, for index counters in loops, as temporary variables, or to hold values that you need onl y inside the method de finition itself Variable declarations consist of a type and a variable name:

i n t m y A ge;

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Examples :

St ri n g my N a me; b o o l e a n isT i r e d ; 2.1 I n teg e r types. T y pe Si z e R a ng e

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byte 8 bi ts —128 to 127

short 16 bits —32,7 68 to 32,767

int 32 bits —2,147, 483,648 to 2,147,483,647 —922337203685477 5808 to 922337203685477 5807 long 64 bits

2.2 F l o a t i ng- p o i n t

This is used for numbers with a decimal part. Java floating-point numbers are compliant with IEEE 7 54 (an international stan da rd for defining floating-point n umbers and a rithmetic).

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There are two floating-point types: float (32 bits, single-precision) and double (64 bits, double-precision). 2.3 Char

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The char type is used for individual characters. Because Java uses the Unicode character set, the char type has 16 bits of precision, unsigned. 2.4 B o o l e a n

2.5 Literals

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The boolean type can ha ve one of two values, true or fa lse. Note that unlike in other C-like languages, boolean is not a number, nor can it be treated as one. All tests of Boolean variables should test for true or fals e.

Literals are used to indicate simple values in your Java

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p ro g rams. Number Literals

• Th e re are several in teger literals. 4, f or examp le, is a decimal integer literal of type int • A decim al integer literal la rger than an int is automatically of type long. • Floating-point literals usual ly have two parts: the integer part and the decim al pa rt—for example, 5.67 77 77.

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B ool ean Lite rals

Boolean literals consist of the keywords true and false. These keywords can be used anywhere needed a test or as the onl y possible values f or boolean variables. 2.6 Character Literals

Character literals are expressed by a single character surrounded by single quotes: 'a', '#', '3', and so on . Characters are stored as 16- bit Unicode cha racters. 3. E x pressions and O p e rators

• Expressions are the simpl est form of statement in Ja va that actually accomplish es something. E x p ressions are statemen ts that return a value. • Operators are special sym b ols that are commonl y used in expressions .

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Arithmetic and tests for equality and magnitude are c ommon examples of expre s s ion s . Because they return a valuethe value can be assi gned to a va riable or test that value in other Java state ments.

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Operators in Java includ e arith metic, vario us forms of assignment, increment and decrement, and l ogical operations. 3.1 A r i t h m e t ic

A r i t h m e tic op e r a tors.

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O p e rat o r Exam Meaning p le + Addition 3+4 — Subtra ction 5 — * Multipl ication 5 * 5 / Division 14 / 7

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Java has five operators for basic arithmetic

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Ex a m ple p r o gram :

c l a s s A r i thmet i c Test {

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pub l i c static v o i d main ( S tring args[ ] ) { sh o r t x = 6; int y = 4; float a = 12.5f;

float b = 7f; Syst e m .out.p rintln("x + y = " +

+ ",

y "

is

( x

+ y)) ;

- y)); Syst e m .out.p rintln("x - y = " ( + x / y)); Sy s t e m.out . p ri n t ln("a is " + a + ", b is "

}}

Sy s t e m.out . p ri n t ln("a / b = " + (a / b));

+ y);

+ b;

Assignment operators.

E x p r e s s i o n Me ani ng x += y

x=x+y

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x

—= y x = x — y

x *= y

x=x*y

x = x / y x /= y

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Incrementing and Decrementing x++ inc rements the value of x by 1 just as if you had used the expression x = x + 1. Similarly x-- d e crem e n ts the val ue of x by 1.

y = x++; y

= + +x;

Comparison operators.

== != < > x

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>= Great er than or equal to x >= 3 Logical Operators

• Exp re ssions that re s ul t in boolean values (for example, th e compa rison operators) can be combine d by using logical operators that repres ent th e logic al c ombinations • AND, OR, XOR, and logical NOT. • For AND combinations, use either th e & or &&. The expression will be true onl y if both express i ons are also true • For OR expressions, use either | or ||. OR exp ressions result in true if either or both of the operands is also true • In ad dition , th e re is the XOR ope rat or ^, which returns true only if its operands are different (one true and one false, or vice versa) and false otherwise (even if both are true). • In gene ral, on l y the && and || are commonly used as ac tual l ogical combination s. &, |, and ^ are more commonly used f or bitwise logical operation s .

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• For NOT, use the ! ope rat or with a single expression argument. The value of the NOT expression is the negation of the expression ; if x is true, !x is fals e.

Bitwise Operators

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These are used to perform operations on individual bits in integers. O p erator Meaning Bitwise AND

|

Bitw ise OR

^

Bitw ise XOR

>

Right shift

>>>

Zero fill right shift

~

Bitw ise c omplement

> y)

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&

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>>>= Zero fill right sh ift assignment (x = x >>> y) x& = y AND assignment (x = x & y) x|=y OR assignment (x + x | y)

x^= y

XOR assignment (x = x ^ y)

O p e r a tor P r e ced e n ce

Operator precedence determines the order in which expressions are evaluated. This, in some cases, can d ete rmin e the overall value of the expression. For example, ta ke the following expression: y= 6+4/2

Depending on whether the 6 + 4 expression or the 4 / 2 expression is evaluated first, the value of y can end up being 5 or 8. In gen e ral, increm ent and decrement Dept. of ISE, SJBIT Page 7

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a re evaluated bef ore arithmetic, arithmetic expressions a re evalua ted bef ore comparison s , and comparisons are evaluat e d be f o re logical expression s . Assignment expressions are evaluat ed last. 4 A r r ays

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Arrays in Java are actual objects that can be passed around and treated just like other objects.

Three steps to create an a rray:

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A r r ays are a way to store a list of items. Each sl ot of the a rray holds an individual element, and you can place elements into or change the contents or those slots as you need to.

Declare a vari a ble to hold the array.

2.

C reate a new arra y object and assign it to the a rray varia bl e.

3.

St ore things in that arra y.

E.g.

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String[] n a m e s; names = new String[10]; names [1] = “n1”; names [ 2 ] = ‘n 2’;

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...

4.1 Mu l t idimensio n a l Arrays

Java does not support multidimension al arrays. However, you can declare and create an arra y of arra ys (an d those arrays can contain a rrays, and so on, f or however many dimensions you need), an d access th e m as you would C-style m ultidimensional arra ys: int coord s [] [] = new int[12] [1 2];

coord s [ 0] [0] = 1; coo rds[0] [1] = 2; 5 C o ntrol S t a t e m e nt 5.1 if C o n d it i o nals

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J a v a a n d J 2 E E 1 0 I S 7 5 3 • Th e if conditional, which ena bles you to execute different bits of code based on a simple test in Java, is nea rly identical to if statemen ts in C. • if con diti onals contain the ke yword if, followed by a bool ean test, fol lowed by a statement (often a block statement) to execute if the test is true: • if (x < y) System.out. println ("x is smaller than y");

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An option a l else keyword p rovi des the statem ent to execute if the test is fa lse: if (x < y)

5.2 T h e C o n di t i o n a l Oper a t or

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System.out.println("x is smaller than y"); else System.out. println("y is b i gger" );

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An alternative to using the if and else keywords in a conditional statement is to use the conditional operator, sometim es called the ternary ope rator. The conditional operator is a ternary operator because it has three terms. Syntax : test ? trueresult : fa lseresult

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The test is an expression that returns true or false, just like the test in the if statement. If the test is true, the conditiona l ope rat or returns the value of tr ueresult; if it's false, it returns the value of falseresult. For example, the following conditional tests the values of x and y, returns the smaller of the two, and assigns that value to the variable smaller: int smal ler = x < y ? x : y;

The con ditional ope rator has a ve ry l ow preceden ce; that is, it's usua lly evaluated only after all its subexpressions are evaluated. The only operators lower in precedence are the assignm ent ope rators.. 5.3 s w itch Conditio n a ls

This is the switch or case statement; in Java it 's switch and beha ves as it does in C: switch (test) valueOne:

{

case

re s u ltOne; Dept. of ISE, SJBIT Page 9

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break;

case valueTwo: re s u ltT w o ; break;

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case valueThree:

break; . . . defau l t : defau l t result; }

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re s u ltThree;

5.4 for L o o ps

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In the switch statement, the test (a primitive type of byte, char, short, or int) is compared with each of the case values in turn. If a match is found, the statement, or statements after the test is executed. If no match is found, the default statement is executed. The default is optional, so if there isn 't a match in any of the cases and de fault doesn 't exist, the switch statement completes without doing anything.

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The f or loop, as in C, repe ats a statement or bl ock of statem ents some number of times until a condition is matche d. for loops are frequently used f or simpl e iteration in which you repeat a block of statements a certain number of times and then stop, but you can use for loops for just about any kind of loop. The for loop in J a va looks roughl y like this:

for (initial izati on; te st; incre m ent) { s t a t e men t s ; }

The start of the for loop has three parts:

• Initialization is an exp ression that initiali zes the start of the loop. If you have a loop index, this expression might declare and initialize it, for example, int i = 0. Variables that you declare in this part of the for loop are local to the loop itself; the y c ease existing after the loop is finishe d executing. Test is the test that occurs after each pass of the loop. The test must be a boolean expression or function that returns a boolean value, for example, i < 10. If the test is true, the loop executes. Once the test is false, the loop stops exec uting

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• Increment is any expression or fun ction call. Commonly, the increment is used to change the value of the loop index to bring the state of the loop closer to returning f alse and completing.

for (i = 0; i < strArray.length; i++) strA rray[i] = "";

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5.5 while and do L o o ps

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String strArray[] = new String[10]; int i; // loop index

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The statement pa rt of the for loop is th e statements that are executed each time the loop iterates. Just as with if, you can include either a single statement here or a block; the previous example used a block because that is more common. Here's an example of a for loop that initia lizes all th e values of a String a rray to null strings:

Finally, there are while and do loops. while and do loops, like for loops, enable a block of Java code to be executed repeate dly until a specific condition is met. Whethe r you use a for loop, a while, or a do is mostly a matter of your pro gra mming style. while and do loop, are exactly the same as in C and C++ except their test condition must be a boolean.

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5.6 while Loops

The while loop is used to repeat a statement or block of statements as long as a particular con dition is true. while loops look like this: while (condition) bodyOfLoop; }

{

The con d i t ion is a boolean expression. If it returns true, the while loop executes the statemen ts in bodyOfLoop and then tests the condition again , repeating until the condition is false: int count = 0;

while ( count < array 1 .length && array 1 [count] !=0) { array2[count] = (float) arra y1[coun t++]; } Dept. of ISE, SJBIT Page 11

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5.7 do...wh i l e L o o ps

The do loop is just like a while loop, except that do executes a given statement or block unti l the condition is false. Th e main difference is that while loops test the condition

do { bodyOfLoop; } while (condi t i on);

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be fore looping, making it possible that th e body of the loop will never execute if the condition is false the first time it's tested. do loops run the body of the loop at least once before testing the condition. do loops l ook like this:

Here, the bodyOfL oop part is the stat ements that are exec uted with each

do {

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int x = 1;

System.out.println("Looping, round " + x); x++; } while (x