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CORE JAVA

SunMicrosystem divided the Java into three groups:

1) J2SE(Java2 Standalone Edition): Deals with developing a standalone application!Core

Java" AdvJava#

2) J2EE(Java2 Enterprise Edition): Deals with developing $usiness application %or &nternet

3) J2ME(Java2 Micro Edition): Deals with developing em$edded system and wireless

application

Java Program Execution:

Features O Java:

1) Simple: Java is simple programming language 'earning and practicing (ava is easy $ecauseits loo) li)e c"c**

+ointers are eliminated in (ava due to the %ollowing reason: i# +ointer creates con%usion %or a programmer

ii# +ointer may crash a program &% we can,t use pointers properly crash occurs

iii# -sing pointers virus and hac)ing programs are developed

2) O!"ect Oriented:

i) O!"ect: An o$(ect is anything that e.ists in the real world O$(ect will have

properties and it may per%orm some actions

Properties: +roperties are represented as varia$les in (ava

#ctions: Actions are represented as methodsAn O$(ect contains varia$les and methods

ii) $lass: A class is a model to create the o$(ects Class does not e.ist physicallyA class also contains properties and actions

3) %istri!uted: Java is distri$uted programming language

&) 'o!ust: &n Ro$ust we have two %eatures:

i# E.ception /andlingii# Memory Management

Memor Mangement: Memory allocation is done $y JVM JVM contains class loader

.(ava .class

0yte code

1

JVM Result

(avac

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su$system to allot memory Memory Deallocation is done $y JVM2ar$age collection 2ar$age collection automatically removed unused

o$(ects

) Porta!le: Java is system independent All (ava program are porta$le $ecause it will give same

result anywhere

*) +ig, Perormance: JVM contains i# J&3 compiler and ii# &nterpreter

J-.: Just in 3ime compiler is use%ul to increase the speed o% the e.ecution

-nterpreter: &nterpreter shows the line num$er

%emo Program:

%emo/"ava

import (avalang45

class Demo6

pu$lic static void main!String78 args#

6

Systemoutprintln!9/ello orld;9#5

<<

import: import is a )eyword which is used to import the pac)ages

"ava: (ava is a (ava li$rary

lang: lang is the name o% the de%ault pac)age

class: Class is a )eyword to de%ine class name

pu!lic: +u$lic data availa$le to all other programmer

static: static )eyword is used to call main method without creating o$(ect

void: void is a return type Main method doesn,t return any value $ut it will e.ecute all the

Statement

main: =ame o% the main method

String0 args: /ere args is the name o% the array 3he type o% the array is String

Sstem: System is a class

out: Out is a static %ield Static %ield can,t changed

>

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println: =ame o% the method

JM #rc,itecture:

JVM is divided into %ive sections:

1# Met,od #rea: &t contains the class code and method code

># +eap: O$(ects are created on /eap memory

?# Java Stac: Java Stac) are the places where (ava methods are e.ecuted

@# P$ 'egister: 3hese registers store memory address o% ne.t instruction to $e e.ecuted $ythe microprocessor

# 4ative Met,od Stac: 3hese are the places where native methods are store

$omments: Comments represents the description o% aim and %eatures o% a program 3he mainadvantage o% comments are Reada$ility Reada$ility means understanda$le $y

everyone 3here are three types o% comments in (ava

i# Single line comment: 3his comment starts with BBii# Multiline comment: 3his comment starts with B4 and ends with 4B

iii# %ocumentation comment: 3his comment starts with B44 and ends with 4B

5: 6,at is an #P- document7

A: !Application +rogramming &nter%ace# &t is a document containing description o% all the %eatures

o% so%tware or product or technology e can create our own A+& document $y using (avadoccommand

5: 6,at is t,e dierence !et8een 9include and import7

A: include ma)es the compiler to copy the entire header %ile code into a c or c** program 3hus itincreases the sie o% the program and waste memory and processor time

&mport ma)es JVM to goto the (ava li$rary" e.ecute the code there" comes $ac) and

su$stitute the result into a (ava program

5: 6,at is J'E(Java 'untime Environment)7

A: JREJVM * Java'i$rary

5: 6,at is command line argument7

A: 3he values pass to main method is called command line argument 3he values store in Stringtype array

?

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4aming 'ule:

1# +ac)age names in (ava are written in all small letters E.: (avalang4"(avaio4 etc

># Each word o% class name and inter%ace name start with a capital letter E.: 3hread" String?# Method name start with a small letter than each word start with a capital letter E.: read!#"

read'ine!# etc

@# Varia$le names also %ollow the a$ove method rule E.: String emp=ame" int emp=um etc# Constant should $e written using all capital letters E.: int %inal +&>>BF" MAG1H etc

I# All )eywords should $e written in all small letters E.: import" pu$lic" static etc

%ata .pe: A datatype represents the type o% data stored in memory

+rimitive Data 3ype or undamental Data 3ype:

-) -nteger %ata .pe

Data 3ype Memory Sie

i# $yte 1$yteii# short > $ytesiii# int @ $ytes

iv# long K $ytes

--) Float %atatpe

i# %loat @ $ytes

ii# dou$le K $ytes

---) $,aracter %atatpe

i# char > $ytes

-) oolean datatpe

i# $oolean 1$it!true or %alse#

5: 6,at is t,e dierence !et8een loat and dou!le7

A: %loat can represent upto F digit a%ter decimal point accurately Dou$le can represent upto 1

digit accurately a%ter decimal point

Operator: An operator is a sym$ol that per%orm some operations

E.: A * 0 !/ere * is an operator and A"0 is called operand#

Operand is a varia$le in which the operator acts An operator can act upon single operand than it iscalled Lunary operator An operator can act upon > operand than it is called L$inary operator &%

an operator act upon ? operand than it is called Lternary operator

@

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Operator in Java:

1# Arithmetic Operator:*"N" " 4" B

># -nary Operator:**" NN?# Assignment Operator: " *" N" 4"

@# Relational Operator: P" P" Q" Q" " ;

# 'ogical Operator: " " ;I# 0oolean Operator: " " ;

F# 0itwise Operators:

a# 0itwise complement: T $# 0itwise and:

c# 0itwise or: !pipe sym$ol#

d# 0itwise GOR:U!cap sym$ol#

K# Dot Operator:a# 3o re%er to a class into pac)age

e.: (avautilDate" (avaio0u%%eredReader

$# 3o re%er to a method o% a class e.: Mathpow!#" Empsum!#

c# 3o re%er to a varia$le in a class e.: Empname" Empno

-ncrement Operator: 3his operator increases the value o% a varia$le $y 1 e have > types in

increment operatorE.: **.

1# Preincrementation: &n +reincrementation " incrementation has done %irst and

any other operation are per%ormed ne.t

E.ample:

BB+reincrementation e.ample

class +re

6

pu$lic static void main!String78 args#6

int .F5

Systemoutprintln!**.#5Systemoutprintln!.#5

Systemoutprintln!**.#5

Systemoutprintln!.#5

<<

># Postincrementation: &n +ostincrementation any other operation is done %irst"

incrementation is per%ormed at the endE.: .**

E.ample:

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BBpostincrementation

class +ost

6 pu$lic static void main!String78 args#

6

int .1K5Systemoutprintln!.**#5

Systemoutprintln!.#5

Systemoutprintln!.**#5Systemoutprintln!.#5

<

<

+re+ost E.ample

class +re+ost

6 pu$lic static void main!String78 args#6

int .?5

BBSystemoutprintln!**.4.**4.**#5

Systemoutprintln!**.4.**4**.#5Systemoutprintln!.#5

<

<

.,e precedence o "ava operators:;;

1# &ncrement and Decrement Operator

># Arithmetic Operations

?# Comparisons@# 'ogical Operations

# Assignment Operations

/ighest!# 78

** NN T ;

4 B

* N

QQ QQQ PP

Q Q P P

I

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;

U

:

op

'owest

=ote: &% eWual precedence than precedence will count %rom le%t to right

E.ample:

class Ope3est

6


int a1H4@*>HB>N5

int $1H4!@*>H#B>N5int c!1H*>H#B*5

int d!1H*>H#B!*#5

Systemoutprintln!a*9 9*$*9 9*c*9 9*d#5

Systemoutprintln!9Value o% a isNNQ9*a#5Systemoutprintln!9Value o% $ isNNQ9*$#5

Systemoutprintln!9Value o% c isNNQ9*c#5

Systemoutprintln!9Value o% d isNNQ9*d#5<

<

.ernar operator:

class 3ernary6

pu$lic static void main!String args78# 6

int i >H5

int ( 5int H5

F

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BB i P ( i : (5 BB ternary operator!output is >H# i Q ( i : (5 BB ternary operator!output is #

Systemoutprintln!93he value assigned is 9 * #5

<<

'everse:

class Reverse


6

int rH"revH5

int nI?IF@5while!nQH#

6

rn1H5rev!rev41H#*r5

nnB1H5<Systemoutprintln!93he Reverse =um$er isNNQ9*rev#5

<

<

$ontrol Statement: E.ecuting the statement one $y one is called SeWuential E.ecution

E.ecuting the statement randomly is called Random E.ecution

Random E.ecution is use%ul to write $etter program Random E.ecution is possi$le $y using control statement Control statements are the statements

which change the %low o% e.ecution o% a program

1# i;else statement: 3his statement is use%ul to per%orm a tas) depending upon whether a

condition is true or %alse

E.ample 1:

class &%3est


6

int numN@5

i%!numH#6

Systemoutprintln!9&t is ero9#5<

else i%!numQH#

6

Systemoutprintln!9&t is positive9#5

K

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<else

6

Systemoutprintln!9&t is negative9#5<

<

<

E.ample >:

BB=ested i%Nelse

class &%Else6

pu$lic static void main!String args78#

6int month @5

String season5i%!month 1> month 1 month >#

6

season 9inter95

<

else i%!month ? month @ month #6

season 9Spring95

<else i%!month I month F month K#

6

season 9Summer95<

else i%!month X month 1H month 11#

6

season 9Autumn95<

else

6season 90ogus Month95

<

Systemoutprintln!9April is in the 9 * season #5

<

<

># do;8,ile loop: 3his loop is used to repeat early e.ecute a group o% statements as long as

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BB%or! i15iP>H5i**#6

Systemoutprintln!i#5

<BBSystemoutprintln!i#5

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# s8itc, statement: Switch statement is use%ul to e.ecute a particular tas) %rom among

several tas) depending upon the value o% a varia$le

E.ample 1:

class Switch3est6


6char colorYgY5

switch!color#6case YrY:Systemoutprintln!9red9#5

$rea)5

case YgY:Systemoutprintln!9green9#5

$rea)5case Y$Y:Systemoutprintln!9$lue9#5

$rea)5

case YwY:Systemoutprintln!9white9#5 $rea)5

case YpY:Systemoutprintln!9pin)9#5

$rea)5de%ault:Systemoutprintln!9=o condition9#5

<

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E.ample >:

class Switch3est1

6


6char colorY>Y5

int a1H"$>H5switch!color#

6

case Y1Y:Systemoutprintln!a*$#5

$rea)5case Y>Y:Systemoutprintln!aN$#5

11

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$rea)5case Y?Y:Systemoutprintln!a4$#5

$rea)5

case Y@Y:Systemoutprintln!aB$#5 $rea)5

case YY:Systemoutprintln!a$#5

$rea)5de%ault:Systemoutprintln!9=o condition9#5

<

<<

Jump Statement:

rea statement 1:

BBhen a $rea) statement is encountered inside a loop" the loop is terminated and programcontrol resumes at the ne.t statement %ollowing the loop

BB -sing $rea) to e.it a loopclass 0rea)'oop

6


6%or!int iH5 iP1HH5 i**#

6

BBi%!i 1H# $rea)5 BB terminate loop i% i is 1HBBH to XBBi%!i 1H# continue5 BBH to1HH e.cept 1H

i%!!i> H## continue5

Systemoutprintln!9i: 9 * i#5<

Systemoutprintln!9'oop complete9#5

<

<

rea statement 2:

BB -sing $rea) with nested loops

class 0rea)'oop>

6 pu$lic static void main!String args78#

6%or!int iH5 iP?5 i**#

6

Systemoutprint!9+ass 9 * i * 9: 9#5

%or!int (H5 (P1HH5 (**#6

1>

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i%!( 1H# $rea)5 BB terminate loop i% ( is 1HSystemoutprint!( * 9 9#5

<

Systemoutprintln!#5<

Systemoutprintln!9'oops complete9#5

<<

$ontinue statement:

BB Demonstrate continue

class Continue


6

%or!int iH5 iP1H5 i**#6

Systemoutprint!i * 9 9#5i% !i> H# continue5Systemoutprintln!99#5

<

<

<

'eturn Statement:

BB3he return statement is used to e.plicitly return %rom a method 3hat is" it causes program

control to trans%er $ac) to the caller o% the method

BB Demonstrate return

class Return


6

$oolean t true5

Systemoutprintln!90e%ore the return9#5

i%!t# BBreturn5 BB return to caller

Systemoutprintln!93his wonYt e.ecute9#5

<

<

#ccept t,e value rom e!oard:

1?

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Stream: A stream represents %low o% data %rom one place to another place

a) -nputStream: &nputStream read or receive data

!) OutputStream: OutputStream send or write data to some other place

4ote: #ll stream classes are availa!le in "ava/io pacage/

Sstem class:

1# Systemin !represent )ey$oard#

># Systemerr !represent monitor and display error messages#

?# Systemou !represent monitor and display general messages#

E.ample 1:

BBAccepting data %rom )ey$oardimport (avaio45

class &nput6

pu$lic static void main!String78 args# throws E.ception

6

B4&nputStreamReader o$(new &nputStreamReader!Systemin#5

0u%%eredReader $rnew 0u%%eredReader!o$(#54B

0u%%eredReader $rnew 0u%%eredReader!new &nputStreamReader!Systemin##5

Systemoutprintln!9Enter a value9#5

BBchar ch!char#$rread!#5

String ch$rread'ine!#5BBint ch1&ntegerparse&nt!ch#5

%loat ch1loatparseloat!ch#5

dou$le ch1Dou$leparseDou$le!ch#5

Systemoutprintln!9Zou have enteredNNQ9*ch1#5<

<

E.ample >:

BBAccepting Employee data

import (avaio45class Empdata

6 pu$lic static void main!String78 args# throws E.ception

6


Systemoutprintln!9Enter &d9#5int id&ntegerparse&nt!$rread'ine!##5

1@

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Systemoutprintln!9Enter se.!MB#9#5char se.!char#$rread!#5

$rs)ip!>#5

Systemoutprintln!9Enter =ame9#5String name$rread'ine!#5

Systemoutprintln!9&dNNQ9*id#5

Systemoutprintln!9Se.NNQ9*se.#5Systemoutprintln!9=ameNNQ9*name#5

<

<

#rra: An array represents a group o% elements o% same data type 0y representing a group o%elements with a single array we can ma)e programming easy

.pes o #rra:

i# One dimensional array 1Dii# 3wo dimensional array >D

iii# Multi dimensional array ?D

1# One dimensional arra 1%: One dimensional array represents a single row o% data or a

single column o% data

$reating One dimensional arra:

i# e can declare and initialie a one dimensional array using assignment operator E.: int mar)s7861H">H"?H"@H"HH5

mar)s7>8?H5

mar)s7?8@H5

mar)s7@8H5

E.ample 1:

BBOne diamansional array e.ampleimport (avaio45

class Arr16


6

0u%%eredReader $rnew 0u%%eredReader!new &nputStreamReader!Systemin##5Systemoutprintln!9/ow many su$(ects9#5

1

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int n&ntegerparse&nt!$rread'ine!##5int mar)s78new int7n85

%or!int iH5iPn5i**#

6Systemoutprintln!9Enter Mar)s9#5

mar)s7i8&ntegerparse&nt!$rread'ine!##5

<int totH5

Systemoutprintln!93he mar)s are9#5

%or!int iH5iPn5i**#6

Systemoutprintln!mar)s7i8#5

tottot*mar)s7i85

<Systemoutprintln!93otal Mar)s9*tot#5

%loat percent!%loat#totBn5

Systemoutprintln!9+ercent 9 *percent#5Systemoutprintln!93he length o% array9*mar)slength#5

<<

E.ample >:

BB3he values pass into the runtimeBBimport (avalang45

class Arr>

6 pu$lic static void main!String a78#

6

int nalength5Systemoutprintln!9=oo% args9*n#5

Systemoutprintln!93he args are9#5

%or!int iH5iPn5i**#

Systemoutprintln!a7i8#5<

<

E.ample ?:

BBCharacter Array!1D#

class CharArray6


char ch786YAY"Y0Y"YCY"YDY

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># .8o dimensional arra 1%: 3wo dimensional array represents several rows columns o%

elements

$reating .8o dimensional arra:

i# e can declare and initialie a two dimensional array using assignment operator E.: int mar)s7878661H">H"?H"I"I@

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Systemoutprintln!#5<

<

<

E.ample ?:

BB&n (ava"a multiNdiamensional array is an array whose components are themselves arrays

class CharMultiArray


6

char ch787866YAY"Y0Y"YCY"YDY

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modi%iedE.: String

E.ample 1:

class Str1


6

String s193his is (ava95Systemoutprintln!9hashcode %or s1NNQ9*s1hashCode!##5

String s>new String!9& li)e9#5

Systemoutprintln!9hashcode %or s>NNQ9*s>hashCode!##5

char arr786YaY"YpY"YtY"YeY"YcY"YhY9*s>#5Systemoutprintln!9s?9*s?#5

Systemoutprintln!93he no o% character in s1 including spaces9*s1length!##5Systemoutprintln!9s1 (oin with s> with s?9*s1concat!s>#*9 9*s>concat!s?##5

BB Systemoutprintln!s1*9 9*s>*9 9*s?#5

$oolean .s1startsith!93his9#5

i%!.#

Systemoutprintln!9s1 starts with 3his9#5else

Systemoutprintln!9s1 does not starts with 3his9#5

String rs1to-pperCase!#5String ss>to-pperCase!#5

String r1s1to'owerCase!#5

Systemoutprintln!9A%ter converting s19*r#5Systemoutprintln!9A%ter converting s>9*s#5

Systemoutprintln!9A%ter converting s19*r1#5

<

<

E.ample >:

class Str>

6


6String s19/ello95

Systemoutprintln!9hashcode %or s1NNQ9*s1hashCode!##5String s>9/ello195

Systemoutprintln!9hashcode %or s>NNQ9*s>hashCode!##5

BBi%!s1s>#

i%!s1eWuals!s>##Systemoutprintln!90oth are eWuals9#5

1X

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elseSystemoutprintln!90oth are not eWuals9#5

<

<

E.ample ?:

class Str?

6


String s19/ello95

Systemoutprintln!s1#5

String s>9/ai95s1s1*s>5

Systemoutprintln!s1#5

<<

B42ar$age Collector remove the previous value and storing the new value4B

E.ample @:

String Methods:

BB1# code+ointAt!#:NN 3he code+ointAt!# method returns the character!-nicode code point# at the

speci%ied inde.

BB># code+oint0e%ore!#:NN 3he code+oint0e%ore!# method returns the character!-nicode code point#

$e%ore the speci%ied inde.

BB?# code+ointCount!#:NN 3he code+ointCount!# method returns the num$er o% -nicode code points

$etween two indices in the String

BB@# startsith!#:NN 3he startsith!# method returns a $oolean value to test whether the string startswith a speci%ied pre%i.

BB# endsith!#:NN 3he endsith!# method returns a $oolean value to test whether the string endswith a speci%ied su%i.

BBI# to-pperCase!#:NN3he to-pperCase!# method converts the characters in the string to upper case

BBF# to'owerCase!#:NN3he to'owerCase!# method converts the characters in the string to lower

case

BBK# valueO%!#:NN3he valueO%!# method returns the string representation o% the speci%ied

argument3he argument can have any one o% the values:$oolean" char" %loat" dou$le" int" long etc

>H

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BBX# toCharArray!#:NN 3he toCharArray!# method copies the content o% the String to a new characterarray

BB1H# eWuals&gnoreCase!#:NN 3he eWuals&gnoreCase!# method compares two strings" ignoring caseand returns a $oolean value &% the strings are eWual the method returns a true value" otherwise

%alse

class StringMethod

6


String str9Aptech 2lo$al 'earning Solutions95

String str19A+3EC/ 2'O0A' 'EAR=&=2 SO'-3&O=S95

char78 array6YAY"YpY"YtY"YeY"YcY"YhY"Y Y"Y2Y"YlY"YoY"Y$Y"YaY"YlY1

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BB@# length!#:NN 3he length!# method returns the total num$er o% characters %rom the String0u%%ero$(ect

BB# replace!#:NN 3he replace!# method replaces characters %rom the String0u%%er o$(ect with newcharacters

BBI# setCharAt!#:NN 3he setCharAt!# method replaces a character %rom the String0u%%er o$(ect witha new character at the speci%ied inde.

BBF# set'ength!#:NN 3he set'ength!# method sets the length o% the String0u%%er to a new value

BBK# capacity!#:NN 3he capacity!# method returns the current capacity o% the String0u%%er o$(ect 3he

capacity is the amount o% storage availa$le %or newly inserted characters" $eyond which an

allocation will occur

BBX# su$string!#:NN 3he su$string!# method creates a new string %rom the string0u%%er o$(ect

class String0u%%erMethod


String0u%%er s$new String0u%%er!9Aptech 2lo$al 'earning Solutions9#5

String0u%%er s$1new String0u%%er!9Aptech 2lo$al 'earning Solutions9#5

Systemoutprintln!s$charAt!F##5BB2Systemoutprintln!s$deleteCharAt!##5

BBAptec 2lo$al 'earning Solutions

char78 arraynew char71H85s$1getChars!H"I"array"H#5

Systemoutprintln!array#5BBAptech

Systemoutprintln!s$1length!##5BB?>Systemoutprintln!s$1replace!>?"?>"9Services9##5

BBAptech glo$al 'earning Services

s$1setCharAt!F"YgY#5

Systemoutprintln!s$1#5BBAptech glo$al 'earning Services

BBs$1set'ength!?#5

Systemoutprintln!s$1#5BBAptech glo$al 'earning Services

s$1set'ength!1?#5

Systemoutprintln!s$1#5

BBAptech glo$alString0u%%er s$>new String0u%%er!#5

Systemoutprintln!s$>capacity!##5BB1ISystemoutprintln!s$1capacity!##5BB@K

BBcapacitylength*1I

String str5

strs$1su$string!F#5Systemoutprintln!str#5BBglo$al 'earning Services

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strs$1su$string!F"1?#5Systemoutprintln!str#5BBglo$al

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OOPS(O!"ect Oriented Programming Sstem)

3he languages li)e c" pascal" %ortron these are called procedural languages $ecause they %ollow an

approach called procedural approach

3he languages li)e c** and (ava called o$(ect oriented $ecause they %ollow an approach called

o$(ect oriented programming approach

Features o OOPS:

1) O!"ect and class

O!"ect: An o$(ect is anything that e.ists in the real world An o$(ect contains properties

and Actions +roperties are represented as varia$les Actions are represented as

methods So an o$(ect contains varia$les and methods Class does not e.ist physically $ut O$(ect does e.ist physically

$lass: A class is a model or idea to create the o$(ects rom the class we create o$(ects Aclass also contains varia$les and methods An o$(ect does not e.ist without a class $ut a

class e.ist without any o$(ects

2) Encapsulation: riting varia$les and methods as a single unit is called encapsulationClass is an e.ample o% encapsulation 3he advantage o% encapsulation is

the programmer can use same name %or the mem$er o% two di%%erent

classes

3) #!straction: /iding unnecessary data %rom the user is called a$straction

&) -n,eritance: +roducing a new class %rom an e.isting class is called inheritance 3he newly

produced class automatically $uilt inherit all the %eatures o% the e.isting

class Reusa$ility o% code is the main advantage o% inheritance

) Polmorp,ism: &% something e.ist in various %orms it is called polymorphism &% a single

method per%orm various tas) it is called polymorphism

*) Message passing: Calling a method is called message passing

#ccess Speciier: An access speci%ier is a )ey$oard that speci%ies how to access the mem$ers o%class or the class itsel% 3here are %our access speci%ier in (ava:

1) Private: +rivate mem$er o% a class are not accessi$le in another class either in the same

pac)age or in another pac)age 3he scope o% private speci%ier is class scope

>?

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2) Pu!lic: +u$lic mem$ers o% a class are availa$le in another class o% same pac)age or o% ananother pac)age 3he scope o% pu$lic spci%ier is glo$al scope

3) Protected: +rotected mem$ers are availa$le in another class in the same pac)age $ut theyare not availa$le in another pac)age class

=ote: +rotected mem$ers are always availa$le to su$classes!inheritance# in the

same pac)age or another pac)age

&) &) %eault: De%ault mem$ers are availa$le in another class in the same pac)age $ut they

are not availa$le in another pac)age class 3he scope o% de%ault speci%ier is pac)age scope

Pro!lem 8it, Private speciier:

Pro!lem 1:

class +erson6

private String name5 private int age5BBString name5

BBint age5

void tal)!#

6Systemoutprintln!9/ello & am NNQ9*name#5

Systemoutprintln!9/ello My Age NNQ9*age#5

<<

class irst3ype

6


6

+erson p1new +erson!#5 p1tal)!#5

+erson p>new +erson!#5 p>name9san95

p>age>5

p>tal)!#5

<<

B4note: De%ect in this program is i% we declare the varia$les as private we canYt use that varia$lein other class4B

>@

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Pro!lem 2:

class +erson

6 private String name9san95

private int age>5

BBString name9.y95BBint age>H5

void tal)!#

6Systemoutprintln!9/elllo & am NNQ9*name#5

Systemoutprintln!9/elllo My Age NNQ9*age#5

<

<class Second3ype

6


+erson p1new +erson!#5 p1tal)!#5+erson p>new +erson!#5

p>name9a$c95

p>age>X5

p>tal)!#5<

<

BB=ote:de%ect in this program is private varia$le canYt $e initialie second time

Pro!lem 3:

class +erson

6

private String name5 private int age5

BBString name5

BBint age5+erson!#BBde%ault constructor

6

name9.y95

age>H5Systemoutprintln!9de%ault constructor9#5

<void tal)!#

6

Systemoutprintln!9/elllo & am NNQ9*name#5

Systemoutprintln!9/elllo My Age NNQ9*age#5<

>

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<class 3hird3ype

6


+erson p1new +erson!#5

+erson p>new +erson!#5 p1tal)!#5

p>tal)!#5

<<

BB=ote: de%ect in this program is de%ault constructor can initialie only one set o% value

$onstructor: A constructor is similar to a method which initialies the instance varia$les o%a class A constructor name and class name should $e same A constructor

may have parameters and may not have parameters A constructor without any

parameter is called de%ault constructor A constructor with one or more parameters is called parameteried constructor A constructor does not return

any value not even void A constructor is called only once at the time o%

creating an o$(ect

5: 6,at is t,e dierence !et8een deault constructor and parameteri

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6thisaa5

this$$5

thiscc5<

void display!#

6

Systemoutprintln!9/ello name isNNQ9*a#5

Systemoutprintln!9/ello age isNNQ9*$#5Systemoutprintln!9/ello age isNNQ9*c#5

<

<

class +aramcon6


6Constru c1new Constru!#5

c1display!#5Constru c>new Constru!#5c>display!#5

Constru c?new Constru!9san9">#5

c?display!#5

Constru c@new Constru!9Ram9"#5c@display!#5

Constru cnew Constru!9...9"K"@#5

cdisplay!#5Constru cInew Constru!9ddd9"?"@@#5

cIdisplay!#5

<<

BB=ote: &n this program we are a$le to get di%%erent set o% values $y using parameteried

constructor" even the varia$le are declared as private

Met,od: A method is a group o% sttements similar to class !or# A method represents a groupo% statements to e.ecute a tas) A method will have two parts:

i) Met,od +eader or Met,od Prototpe: 3his part contains method name" method

parameters and method return type

ii) Met,od od: A method $ody represents a group o% statements containing logicwritten inside 6 <

&% a method returns some values we should use return statements inside to the method

$ody e can return only one entity

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Met,od 6it,out 'eturn .pe Example:

BBMethod without return type

class rt6

dou$le d1"d>5

rt!dou$le ."dou$le y#BB+arameteried constructor 6

d1.5

d>y5<

void sum!#

6

dou$le d?d1*d>5Systemoutprintln!9sum9*d?#5

<

<class Demort


rt snew rt!1H?">H#5

ssum!#5

rt s1new rt!1H@II">HI#5s1sum!#5

<

<

Met,od 6it,'eturn .pe Example:

BBMethod with return type

class ithrt

6

dou$le d1"d>5ithrt!dou$le ."dou$le y#

6

d1.5d>y5

<

dou$le sum!#

6BBdou$le d?d1*d>5

BBreturn d?5return d1*d>5

<

<

class Demoithrt6

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ithrt snew ithrt!1H?">H#5

Systemoutprintln!9sum9*ssum!##5ithrt s1new ithrt!>?"1>I#5

Systemoutprintln!9sum9*s1sum!##5

<<

.pes o Met,ods:

1) Static Met,od: Static methods are the methods which does not act upon the instance

varia$les o% a class Static methods are declared as static $y using a static

)eyword Static methods are called using classnamemethodname /ere noneed to create an o$(ect Static methods can act upon static varia$le Static

varia$le should $e declared as static

E.: static dou$le d1"d>"d?5

E.ample:

BBStatic method e.ample

class Sta

6

BBstatic int a1H5static int a11H5

static void display!#6

Systemoutprintln!a1#5

<<

class Static

6


Stadisplay!#5

<<

2) -nstance Met,od: 3hese are the methods which act upon instance varia$les o% a class

&nstance methods are called using o$(ectnamemethodnamea) #ccessor Met,od: 3hese methods access or read the instance

varia$les

!) Mutator Met,od: 3hese methods not only read the instance varia$le $ut also

modi%ies the contents o% the o$(ect

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E.ample:

BBAccesor and Mutator method

class +erson6

String name5

int age5char se.5

+erson!String name"int age"char se.#

6thisnamename5

thisageage5

thisse.se.5

<BBAccesor Method

void display!#

6Systemoutprintln!9=ameNNQ9*name#5

Systemoutprintln!9AgeNNQ9*age#5Systemoutprintln!9Se.NNQ9*se.#5

<

BBMutator Method

+erson modi%y!+erson o$(#

6o$(name9yyy95

NNo$(age5

o$(se.YY5return o$(5

<

<class MutaAcc

6


6+erson pnew +erson!9...9"?I"YMY#5

pdisplay!#5

+erson p1pmodi%y!p#5BB/ere we are not creating an o$(ect to p1 /ere p1 is a re%erence varia$le

p1display!#5

pdisplay!#5

+erson p>new +erson!9sai9">>"YMY#5 p>display!#5

<<

3) Factor Met,od: A actory method is a method that returns an o$(ect o% the class to

which it $elongs All the actory methods are static method hen weuse actory Method we can not use new operator

?H

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E.ample:

BBE.ample %or actory Methodimport (avate.t45

class actMe


6

%inal dou$le +&!dou$le#>>BF5dou$le r@KF5

dou$le area+&4r4r5

Systemoutprintln!9Area9*area#5

=um$erormat o$(=um$erormatget=um$er&nstance!#5o$(setMa.imumractionDigits!>#5

String stro$(%ormat!area#5

Systemoutprintln!9ormatted Area9*str#5o$(setMinimumractionDigits!I#5

String str1o$(%ormat!area#5Systemoutprintln!9ormatted Area9*str1#5

<

<

-nner $lass: A class within another class is called inner class e can not write private $e%oremain class +rivate can $e used only $e%ore inner class &nner class not availa$le to

the other programmer e can create an o$(ect to inner class only in its outer class

E.ample:

BB&nner class e.ample

class 0an)AcctBBOuter class

6

private dou$le $al5

0an)Acct!dou$le $#

6 $al$5

<

void start!dou$le r#

6&nterest innew &nterest!r#5

incalculate&nterest!#5<

private class &nterestBB&nner class

6

private dou$le rate5&nterest!dou$le r#

?1

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6rater5

<

void calculate&nterest!#6

dou$le interest$al4rateB1HH5

Systemoutprintln!9&nterest9*interest#5 $al*interest5

Systemoutprintln!90alance9*$al#5

<<

<

class &nnerDemo


6

0an)Acct acctnew 0an)Acct!1HHHHH#5acctstart!?#5

<<

-n,eritance: +roducing a new class %rom an e.isting class is called inheritance 3he e.istingclass is called super class and the newly produced class is called su$ classSu$class o$(ect contains copy o% the super class 3he main advantage o%

inheritance is the reusa$ility o% the code e can create an o$(ect to the su$class

only in inheritance

.pes o -n,eritance:

1# Single &nheritance># Multilevel &nheritance

?# Multiple &nheritance

@# /ierarchical &nheritance# /y$rid &nheritance

E.ample 1:

BBE.ample o% &nheritance!using setters and getters methods#

class 3eacher

6

int id5String name"addr5

void set&d!int id#6

thisidid5

<

int get&d!#6

?>

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return id5<

void set=ame!String name#

6thisnamename5

<

String get=ame!#6

return name5

<void setAddr!String addr#

6

thisaddraddr5

<String getAddr!#

6

return addr5<

<

class Student e.tends 3eacher

6

int mar)s5

void setMar)s!int mar)s#6

thismar)smar)s5

<int getMar)s!#

6

return mar)s5<

<

class &nherit6


6Student stnew Student!#5

stset&d!1#5

stset=ame!9...9#5

stsetAddr!91?1N>>"+3 colony"DS=R9#5stsetMar)s!XK#5

Systemoutprintln!9&D9*stget&d!##5Systemoutprintln!9=AME9*stget=ame!##5

Systemoutprintln!9ADDRESS9*stgetAddr!##5

Systemoutprintln!9MAR]S9*stgetMar)s!##5

<<

??

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=ote: a# rom a$ove program all the 3eacher class mem$ers are availa$le to student class

$# 3o access or read all the mem$ers o% 3eacher class!Super class# to Student class!Su$class# we use e.tends )eyword

E.ample >:

class OneDemo

6OneDemo!#

6

Systemoutprintln!9OneDemo in super class;9#5

<<

class 3woDemo e.tends OneDemo

6

3woDemo!#6Systemoutprintln!93woDemo in su$ class9#5

<

<

class 3Demo e.tends 3woDemo6

3Demo!#6

Systemoutprintln!93Demo in su$ class9#5

<<

class &nheritDemo

6


3Demo tnew 3Demo!#5

<<

=ote: a# rom a$ove program %irst super class constructor is e.ecuted and than the su$ class

constructor is e.ecuted $# Super class parameteried constructor is not availa$le to su$ class

c# Super is a )eyword that re%ers to super class %rom a su$ class &t means super can re%er

super class instance varia$le" super class constructor and also super class methods

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a# Static polymorphism $# Dynamic polymorphism

%namic polmorp,ism: Dynamic means at runtime 3he polymorphism e.ecuted at runtime iscalled dynamic polymorphism or runtime polymorphism or dynamic

$inding or dynamic lin)ing /ere (ava compiler does not )now which

method is called $y the user at the time o% compilation JVM can $indthe method" call with the method $ody at the time o% running the

program

E.ample:

Met,od Overloading: riting two or more methods with the same name $ut with di%%erent

method Signature

BBMethod Overloading

class Sample

6 void add!int a"int $#

6Systemoutprintln!9sum o% two9*!a*$##5

<

void add!int a"int $"int c#

6

Systemoutprintln!9sum o% three9*!a*$*c##5

<

<class +oly

6


Sample snew Sample!#5

sadd!1H">H#5

sadd!1H">H"?H#5<

<

Met,od Signature: Method Signature represents method name and method parameters hen two

or more methods are written with the same method name and there is a

di%%erence in the method signature %rom can identi%y those method s di%%erent

method

3he di%%erence in the method signature may $e due to the %ollowing %actor:

a# 3here may $e a di%%erence in the num$er o% parameter

E.: void add!int a" int $#

void add!int a" int $" int c#

?I

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$# 3here is a di%%erence in the data type o% parametersE.: void add!int a" int $#

void add!%loat a" %loat $#

c# 3here is a di%%erence in the seWuence o% parameters

E.: int swap!int a" char $#

&nt swap!char a" int $#

Met,od Overriding: riting two or more methods in super and su$ classes with the same nameand same signature is called method overriding &n method overriding JVM

e.ecute a method depending on the data type o% re%erence varia$le used to

call a method

E.ample:

BBMethod Overridingclass One

6 void calculate!dou$le .#6

Systemoutprintln!9SWuare9*!.4.##5

<

<

class 3wo e.tends One

6void calculate!dou$le .#

6

supercalculate!>#5Systemoutprintln!9SWuare root value9*

MathsWrt!.##5

<

<class +oly1

6


3wo tnew 3wo!#5

tcalculate!>#5tcalculate!X#5

tcalculate!?I#5<

<

Static Polmorp,ism: 3he +olymorphism e.ecuted at compile time is called static polymorphismor static $inding

?F

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=se o Final e8ord:

1# inal )eyword is writing $e%ore constants

># inal )eyword is used $e%ore the class name to prevent inheritance?# inal methods can not $e overridden

.pe $asting or $asting:Converting one data type into another type is called type casting or

casting

$asting primitive data tpe:

1) 6idening: Casting a lower data type into a higher data type is called widening

E.: char ch \A,

int i !int# ch5BBI

2) 4arro8ing: Converting a higher data type into lower type is called =arrowing

E.: int n I5 Char ch !char# n5

#!stract class: A method consists o% two parts: method header and method $ody Methodheader represents the %uture the programmer wants in a class Method $ody

represents how to implements this %uture &mplementing means writing $ody%or method hen a method has got di%%erent implementation in di%%erent

o$(ects than the programmer cannot write method $ody in the super class

A method without method $ody is called a a$stract method A class thatcontains a$stract method is called a$stract class 3o declare a$stract method

class should $e declare using )eyword a$stract Concrete methods meancomplete methods e cannot create o$(ect to a$stract class

Points:

1# An a$stract class is a class with ero or more a$stract methods

># An a$stract class can have a$stract method" concrete method and instance

varia$les?# 0oth the a$stract class and a$stract methods should $e declared as a$stract

@# e cannot create an o$(ect to a$stract class

# e can create re%erence varia$les o% a$stract class type

I# All the a$stract methods o% a$stract class should $e implemented in itssu$classes

F# &% any method is not implemented that su$class should also $e declare as

a$stractK# A$stract class re%erence varia$le can $e used to re%er to the o$(ects

X# A$stract class re%erence cannot re%er to individual method o% a class

1H# A class cannot have $oth a$stract and %inal

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E.ample:

a$stract class Car

6int regno5

Car!int regno#

6thisregnoregno5

<

void %ill3an)!#BBconcrete method6

Systemoutprintln!9ill 3an)9#5

<

a$stract void steering!int direction#5a$stract void $rea)ing!int %orce#5

<

class Maruti e.tends Car 6

Maruti!int regno#6

super!regno#5

<

void steering!int direction#6

Systemoutprintln!9Regno o% Maruti9*regno#5

Systemoutprintln!9Maruti uses manual steering9*direction#5Systemoutprintln!9please drive the maruti car9#5

<

void $rea)ing!int %orce#6

Systemoutprintln!90rea)ing o% Maruti9*%orce#5

Systemoutprintln!9Maruti uses hydralic $rea)s9#5

Systemoutprintln!9Apply $rea)s stop the car9#5<

<

class Santro e.tends Car 6

Santro!int regno#

6

super!regno#5<

void steering!int direction#6

Systemoutprintln!9Regno o% Santro9*regno#5

Systemoutprintln!9Santro uses manual steering9*direction#5

Systemoutprintln!9please drive the Santro car9#5<

?X

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void $rea)ing!int %orce#6

Systemoutprintln!90rea)ing o% Santro9*%orce#5

Systemoutprintln!9Santro uses hydralic $rea)s9#5Systemoutprintln!9Apply $rea)s stop the car9#5

<

<class A$stractDemo

6


Maruti mnew Maruti!IIII#5

Santro snew Santro!XXXX#5

Car c"c15cm5

c1s5

c%ill3an)!#5csteering!>#5

c$rea)ing!>HH#5

c1%ill3an)!#5

c1steering!>#5

c1$rea)ing!>HH#5

<<

-nterace: An inter%ace is a speci%ication o% method prototype All the methods o% inter%ace are $y de%ault a$stract only e cannot create an o$(ect to inter%ace

Points:

1# &nter%ace is a speci%ication o% method prototype or method header># An inter%ace contains ero or more a$stract methods

?# All the methods o% the inter%ace are pu$lic and a$stract $y de%ault

@# An inter%ace can also contain varia$les which are pu$lic" static and %inal $y

de%ault# hen an inter%ace is written any third party vendor can implement it

I# All the a$stract method o% the inter%ace should $e implemented in a class called

implementation class

F# &% any method is not implemented than that class should $e declare as a$stractK# e cannot create an o$(ect to an inter%ace

X# e can create a re%erence o% an inter%ace1H# &nter%ace re%erence can $e used to re%er to the o$(ects o% its implementation

classes

11# e can write a class within an inter%ace

1># An inter%ace cannot implement another inter%ace1?# An inter%ace can e.tends another inter%ace

@H

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1@# A single class can implement multiple inter%aces

E.ample1:

import (avaio45

inter%ace My&nter

6void connect!#5

<

class OracleD$ implements My&nter

6

pu$lic void connect!#

6Systemoutprintln!9Connecting to oracle9#5

<

<class Sy$aseD$ implements My&nter

6 pu$lic void connect!#6

Systemoutprintln!9Connecting to sy$ase9#5

<

<class &nter

6

pu$lic static void main!String78 args# throws E.ception6

B4Class cClass%or=ame!args7H8#5

My&nter mi!My&nter#cnew&nstance!#5miconnect!#54B

OracleD$ o$new OracleD$!#5Sy$aseD$ s$new Sy$aseD$!#5

My&nter m1"m>5

m1o$5m1connect!#5

m>s$5

m>connect!#5

<<

E.ample >:

BBAn &nter%ace can e.tends more than one inter%ace"$ut one inter%ace canYt implements another

inter%ace

@1

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inter%ace irst6

void disp1!#5

<inter%ace Second

6

void disp>!#5<

inter%ace 3hird e.tends irst"Second

6void disp?!#5

<

class 3est implements 3hird

6 pu$lic void disp?!#

6

Systemoutprintln!9disp?!#9#5<

pu$lic void disp1!#6

Systemoutprintln!9disp1!#9#5

<

pu$lic void disp>!#

6Systemoutprintln!9disp>!#9#5

<

<class &nter1

6


3est tnew 3est!#5

tdisp1!#5

tdisp>!#5tdisp?!#5

BBSystemoutprintln!9/ello orld;9#5

<<

E.ample ?:

BBclass inside inter%ace

inter%ace Outer 6

void disp!#5

class &nner

6void test!#

@>

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6Systemoutprintln!9&nner9#5

<

<<

class Main implements Outer

6 pu$lic void disp!#

6

Systemoutprintln!9disp9#5<

<

class &nter>

6


6Main mnew Main!#5

mdisp!#5Outer&nner inew Outer&nner!#5itest!#5

Systemoutprintln!9/ello orld;9#5

<

<

Multiple -n,eritance: Java doesn,t support multiple inheritance e can achieve multiple

inheritance $y using multiple inter%aces

E.ample:

BBMultiple inheritance $y using multiple inter%ace

inter%ace ather

6

int +RO+1HHHH5%loat /31I>5

<

inter%ace Mother 6

int +RO+>>HHHH5

%loat /3>@5

<class Child implements ather"Mother

6void property!#

6

Systemoutprintln!9Child property9*!+RO+1*+RO+>##5

<void height!#

@?

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6Systemoutprintln!9Child height9*!/31*/3>#B>#5

<

<class Multi

6


Child cnew Child!#5

cproperty!#5cheight!#5

<

<

Pacages: A pac)ages represents a su$ directory that contains a group o% related classes andinter%aces +ac)ages hide classes and inter%aces in separate su$directories Accidental

deletion is not possi$le 3he classes o% one pac)age are di%%erent %rom the classes o%another pac)age +ac)ages provide the reusa$ility o% code e can create our own

pac)age as well as e.tend already availa$le pac)ages

E.ample 1

Addition(ava

pac)age ddd5

pu$lic class Addition

6dou$le d1"d>5

pu$lic Addition!dou$le d1"dou$le d>#

6thisd1d15

thisd>d>5

< pu$lic void sum!#

6

Systemoutprintln!9sum9*!d1*d>##5

<<

=ote: Q (avac _d Addition(ava

-seAdd(ava

import dddAddition5class -seAdd

6


6Addition anew Addition!>@"?@#5

@@

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Addition a1new Addition!>"?#5BBdddAddition anew dddAddition!>"#5

asum!#5

a1sum!#5<

<

E.ample >:

MyDate(ava

pac)age cd%5

pu$lic inter%ace MyDate

6void showDate!#5

<

MyDate&mpl(ava

pac)age cd%5import (avautilDate5

pu$lic class MyDate&mpl implements MyDate

6

pu$lic void showDate!#6

Date dnew Date!#5

Systemoutprintln!d#5<

<

-seinter%ace(ava

import cd%MyDate&mpl5

class -seinter%ace6


6MyDate&mpl mnew MyDate&mpl!#5

mshowDate!#5

<

<

Su!Pacage Example

Sample(ava

pac)age demoaptech5 pu$lic class Sample

@

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6 pu$lic void show!#

6

Systemoutprintln!9su$ pac)ages9#5<

<

-seSample(ava

import demoaptechSample5class -seSample

6


6Sample snew Sample!#5

sshow!#5

<<

Exception +andling:

ug: A $ug is an error in so%tware De$ugging means removing the errors

.pes o Error:

1) $ompile time error: 3hese are the errors in the synta. or grammar o% the language 3hese

errors are detected $y the compiler at the time o% compilation Des)chec)ing!line $y line# is the solution %or compile time errors

2) 'untime error: 3hese errors will arise due to ine%%iciency !enough memory not availa$le#or una$le to e.ecute the statement $y processor E.: something divides $y

ero Runtime errors are detected $y JVM

3) >ogical error: 3hese are the errors in the logic o% the program 3hese errors are not

detected $y the compiler or JVM 3he programmer is completely

responsi$le %or logical errors

Exception: An E.ception represents runtime errors

$,eced Exception: 3he E.ception which are detected $y (ava compiler at the time o%compilation are called Chec)ed E.ception

=nc,eced Exception: 3he e.ception which are not detected $y (ava compiler and they aredetected $y JVM at runtime are called -nchec)ed E.ception:

=ote: An E.ception is an error that can $e handled $ut an error cannot $e handled

@I

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E.ample:

BBwithout handling

class E.ce11

6


Systemoutprintln!9open the %iles9#5

int nargslength5Systemoutprintln!9=um$er o% args areNNQ9*n#5

int a@Bn5

Systemoutprintln!a#5

int a17861H">H# hen there is an e.ception JVM stores e.ception details in the E.ception Stac) &n catch

$loc) the programmer should display e.ception details and also any messages to the user

?# 3he programmer should close all the %iles and data$ases and per%orm cleanup operation $y

writing them in %inally $loc) 3he statements inside %inally $loc)s are always e.ecuted

wether there is an e.ception or not

E.ample:

BBhandling the e.ception

class E.ce1

6


Systemoutprintln!9open the %iles9#5try

6

int nargslength5

Systemoutprintln!9=um$er o% args are9*n#5int a@Bn5

@F

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6Systemoutprintln!9array is out o% $ounds : 9*e#5

<

<catch!ArithmeticE.ception e#

6

Systemoutprintln!9division $y ero : 9*e#5<

<<

E.ample:

class =ested3ryMethods

6

static void nested3ry!int no#BBMethod6

try 6

Systemoutprintln!9[n &=S&DE S3A3&C ME3/OD9#5

i%!no1#

nonoB!noNno#5

i%!no ># 6

int a78 68 FF5 <

<

catch!E.ception e# 6

Systemoutprintln!9%rom method : : 9*e#5

<

< pu$lic static void main!String ar78#

6

try6

int n"res5

n arlength5

Systemoutprintln!9 =o o% Command 'ine Arguments 9*n#5 res Bn5

Systemoutprintln!9 Result 9*res#5 Systemoutprintln!90e%ore &nvlo)ing nested3ry!n# Value o% = 9*n#5

nested3ry!n#5

<

catch!E.ception e# 6

@X

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c7?18 FKX5%or!int iH5iPclength5i**#

Systemoutprintln!c7i8#5

<

catch!Array&nde.OutO%0oundsE.ception e#

6Systemoutprintln!9Array &nde. Violation 9*e#5

<

catch!ArithmeticE.ception e#

6

Systemoutprintln!9Divide $y ero9*e#5

<

catch!E.ception e#

6Systemoutprintln!9 %rom Super class E.ception 9*e#5

<

%inally

6

Systemoutprintln!9a%ter Catch9#5

<<

<

E.ample:

BBE.ample %or userde%ined e.ceptionclass MyE.ce e.tends E.ception

6

private static int accno7861HH1"1HH>"1HH?"1HH@

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Systemoutprintln!accno7i8*9[t9*name7i8*9[t9*$al7i8#5i%!$al7i8P>HHH#

6

B4MyE.ce menew MyE.ce!90alance amount is less9#5throw!me#54B

throw new MyE.ce!90alance amount is less9#5

<<

<

catch!MyE.ce me#6

BBSystemoutprintln!me#5

meprintStac)3race!#5

<<

<

E.ample:

class MyE.ception e.tends E.ception6

private int data5

MyE.ception!int n#

6 data n5

Systemoutprintln!9&n MyE.ception 9#5

< pu$lic String toString!#

6

return 9 E.ception raised due to low $al 79*data*9895 <

<

class -serDe%inedE.ce6

static void chec)!int no# throws MyE.ception

6 Systemoutprintln!9&n Chec)!9*no*9#9#5

i%!noPHH#

throw new MyE.ception!no#5 Systemoutprintln!9=ormal E.it9#5

< pu$lic static void main!String ar78#

6

try

6chec)!1HHH#5

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chec)!?H#5 <

catch!MyE.ception me#

6 Systemoutprintln!me#5

<

<

<

Exception >ist:

E.ception Meaning:

1# ArithmeticE.ception Arithmetic error" such as divideN$yNero

># Array&nde.OutO%0oundsE.ception Array inde. is outNo%N$ounds

?# ArrayStoreE.ception Assignment to an array element o% an incompati$letype

@# ClassCastE.ception invalid cast

# &llegalArgumentE.ception &llegal argument used to invo)e a method

I# &llegalMonitorStateE.ception &llegal monitor operation" such as waiting on an

unloc)ed thread

F# &llegalStateE.ception environment or application is in incorrect state

K# &llegal3hreadStateE.ception ReWuested operation not compati$le with current

thread state

X# &nde.OutO%0oundsE.ception Some type o% inde. is outNo%N$ounds

1H# =egativeArraySieE.ception array created with a negative sie

11# Class=otoundE.ception class not %ound

1># Clone=otSupportedE.ception Attempt to clone an o$(ect that does not

implement the Clonea$le inter%ace

1?# &llegalAccessE.ception Access to a class is denied

1@# &nstantiationE.ception Attempt to create an o$(ect o% an a$stract class or inter%ace

1# &nterruptedE.ception One thread has $een interrupted $y another thread

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1I# =oSuchieldE.ception A reWuested %ield does not e.ist

1F# =oSuchMethodE.ception A reWuested method does not e.ist

1K# =ull+ointerE.ception invalid use o% a null re%erence

1X# =um$erormatE.ception invalid conversion o% a string to a numeric %ormat

>H# SecurityE.ception Attempt to violate security

>1# String&nde.OutO%0oundsE.ception Attempt to inde. outside the $ounds o% a string

>># -nsupportedOperationE.ception An unsupported operation was encountered

6rapper $lass: A wrapper class is a class whose o$(ect contains a primitive data type

$,aracter class: A Character class contains a value o% primitive type char in an o$(ect An o$(ect

o% type Character contains a single %ield whose type is char

E.ample:

BBCharacter 3estimport (avaio45

class Char3est

6



Systemoutprintln!9+lease Enter a character9#5char ch!char#$rread!#5

i%!CharacterisDigit!ch##

Systemoutprintln!9&t is a Digit9#5else i%!Characteris-pperCase!ch##

Systemoutprintln!9&t is capital9#5

else i%!Characteris'owerCase!ch##

Systemoutprintln!9&t is small9#5else i%!CharacterisSpaceChar!ch##

Systemoutprintln!9&t is coming %rom space$ar9#5

else i%!Characterishitespace!ch##

Systemoutprintln!9&t is coming %rom enter"ta$9#5else

Systemoutprintln!9Sorry & donot )now that character9#5<

<

@

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te class: A 0yte class contains a value o% primitive type $yte in an o$(ect An o$(ecto% type 0yte contains a single %ield whose type is $yte

E.ample:

import (avaio45

class 0yte3est6



Systemoutprintln!9Enter %irst $yte no9#5

String s1$rread'ine!#5

0yte $1new 0yte!s1#5Systemoutprintln!9Enter second $yte no9#5

String s>$rread'ine!#5

0yte $>new 0yte!s>#5int n$1compare3o!$>#5

Systemoutprintln!9Compare3o!# methods return the di%%erence $etween twono9*n#5

i%!nH#

Systemoutprintln!90oth are eWual9#5

else i%!nQH#

Systemoutprintln!9$1 is $igger9*$1#5else

Systemoutprintln!9$1 is smaller9*$1#5

<<

-nteger class: A &nteger class contains a value o% primitive type int in an o$(ect An o$(ecto% type &nteger contains a single %ield whose type is int

E.ample:

import (avaio45

class &nt3est6

pu$lic static void main!String78 args# throws &OE.ception

6

0u%%eredReader $rnew 0u%%eredReader!new

&nputStreamReader!Systemin##5Systemoutprintln!9Enter a num$er9#5

String str$rread'ine!#5

int n&ntegerparse&nt!str#5

Systemoutprintln!9&n decimalNNQ9*n#5str&ntegerto0inaryString!n#5

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Systemoutprintln!9&n $inaryNNQ9*str#5str&ntegerto/e.String!n#5

Systemoutprintln!9&n he.adecimalNNQ9*str#5

str&ntegertoOctalString!n#5Systemoutprintln!9&n octalNNQ9*str#5

<

<

-OStream:

Stream: A stream represents %low o% data %rom one place to another place 3here are two types o%

stream:

1) -nputStream: &nputStream read or accept data that is coming %rom some other place

2) OutputStream: OutputStream send or write data to some other place

te Stream: 0yte Stream handles the data in the %orm o% $its and $ytes 3o handle the data in the%orm o% $ytes the a$stract class &nputStream or OutputStream are used

-nputStream %ivision:

1# ile&nputStream

># ilter&nputStream

a# 0u%%ered&nputStream

$# Data&nputStream?# O$(ect &nputStream

OutputStream %ivision:

1# ileOutputStream

># ilterOutputStreama# 0u%%eredOutputStream

$# DataOutputStream

?# O$(ect OutputStream

$,aracterStream or .extStream: 3hey will handle the data in the %orm o% chracters

'eader %ivision:

1# 0u%%eredReader

># CharArrayReader ?# &nputStreamReader

a# ileReader

@# +rintReader

I

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E.ample ?:

BB-sing riter create and pass the data into the %ile

import (avaio45class Create>

6

pu$lic static void main!String78 args# throws &OE.ception6

String str93his is an &nstitute & am a student95

ileriter %wnew ileriter!9te.t%ilet.t9"true#50u%%eredriter $wnew 0u%%eredriter!%w#5

%or!int iH5iPstrlength!#5i**#

$wwrite!strcharAt!i##5

$wclose!#5<

<

E.ample @:

BBReading %ile using ileReader import (avaio45

class Read>

6

pu$lic static void main!String78 args# throws &OE.ception6

ileReader %rnew ileReader!9te.t%ilet.t9#5int ch5

while!!ch%rread!##;N1#

Systemoutprint!!char#ch#5%rclose!#5

<

<

E.ample :

BBAccept %ile name %rom )ey$oard and display the contentimport (avaio45

class ile=ame

6


try6


Systemoutprintln!9Enter %ile name9#5

String %name$rread'ine!#5ile&nputStream ssnew ile&nputStream!%name#5

K

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0u%%ered&nputStream $innew 0u%%ered&nputStream!ss#5int ch5

while!!ch$inread!##;N1#

Systemoutprint!!char#ch#5 $inclose!#5

<

catch!E.ception %e#6

Systemoutprintln!9ile not %ound9*%e#5

<<

<

E.ample I:

BB`ipping a %ile contents

import (avaio45import (avautilip45

class `ip6

pu$lic static void main!String78 args# throws &OE.ception

6

ile&nputStream %isnew ile&nputStream!9Myilet.t9#5

ileOutputStream %osnew ileOutputStream!9ile1ip9#5De%laterOutputStream dosnew De%laterOutputStream!%os#5

int data5

while!!data%isread!##;N1#doswrite!data#5

%isclose!#5

dosclose!#5%osclose!#5

<

<

E.ample F:

BB-nip the %ile contentsimport (avaio45

import (avautilip45

class -nip

6 pu$lic static void main!String78 args# throws &OE.ception

6ile&nputStream %isnew ile&nputStream!9ile1ip9#5

ileOutputStream %osnew ileOutputStream!9ile>doc9#5

&n%later&nputStream iisnew &n%later&nputStream!%is#5

int data5while!!dataiisread!##;N1#

X

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BBSystemoutprintln!data#5%oswrite!data#5

BBiisclose!#5

%osclose!#5<

<

Seriali implements Serialia$le

6

pu$lic static int a5 pu$lic %loat $5

pu$lic String c5

pu$lic Ctwo>!int a1"%loat $1"String c1#6

aa15

$$15

cc15<

pu$lic void print!#6

Systemoutprintln!9value o% a9*a#5

Systemoutprintln!9value o% $9*$#5

Systemoutprintln!9value o% c9*c#5<

IH

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<

BBimplements Serialia$le inter%ace

import (avaioSerialia$le5 pu$lic class Ctwo implements Serialia$le

6

pu$lic int varone5 pu$lic %loat vartwo5

pu$lic String varthr5

<

BBSerialiation Demo

import (avaio45 pu$lic class Ser1

6


BBCone onew Cone!#5Ctwo onew Ctwo!#5ovarone1H5

ovartwo>>%5

ovarthrnew String!9/ello9#5

ileOutputStream %osnew ileOutputStream!93estSer19#5O$(ectOutputStream oosnew O$(ectOutputStream!%os#5

ooswriteO$(ect!o#5

<<

BBDeSerialiation Demoimport (avaio45

pu$lic class DeSer1

6


Ctwo onull5

ile&nputStream %isnew ile&nputStream!93estSer19#5O$(ect&nputStream oisnew O$(ect&nputStream!%is#5

o!Ctwo#oisreadO$(ect!#5

Systemoutprintln!ovarone#5

Systemoutprintln!ovartwo#5Systemoutprintln!ovarthr#5

<<

BB-sing transient )eyword var%r varia$le is not serialia$le

import (avaio45 pu$lic class Ser>

I1

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6

Ctwo1 onew Ctwo1!#5ovarone>H5

ovartwo?>?%5

ovarthrnew String!9hai9#5ovar%rnew Cone!#5

ileOutputStream %osnew ileOutputStream!93estSer>9#5

O$(ectOutputStream oosnew O$(ectOutputStream!%os#5ooswriteO$(ect!o#5

<

<

import (avaio45

pu$lic class Ser?


6Ctwo> onew Ctwo>!1H">H>>%"9...9#5oprint!#5

ileOutputStream %osnew ileOutputStream!93estSer>9#5

O$(ectOutputStream oosnew O$(ectOutputStream!%os#5

ooswriteO$(ect!o#5ile&nputStream %isnew ile&nputStream!93estSer>9#5

O$(ect&nputStream oisnew O$(ect&nputStream!%is#5

o!Ctwo>#oisreadO$(ect!#5Systemoutprintln!oa#5

Systemoutprintln!o$#5

Systemoutprintln!oc#5<

<

.,reads: A thread represents a process or e.ecution o% statements

Microprocessor uses internally a thread to e.ecute the program

E.ecution process or wor)ed is called thread

E.ample:

class 3hr16


6

Systemoutprintln!93his is %irst statement9#53hread t3hreadcurrent3hread!#5

I>

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tset=ame!9Mythread9#5Systemoutprintln!tisAlive!##5

Systemoutprintln!93hread name is9#5

Systemoutprintln!9current thread9*t#5<

<

=ote: Every (ava program contains internally a thread called main/

De%ault priority o% main thread is 3hread group name is main

Executing statements is o 2 tpes:

1) Single .asing: E.ecuting only one tas) at a time is called single tas)ing

2) Multitasing: &n multitas)ing several program e.ecuting at a time e have two types in

Multitas)ing

a# Process !ased multitasing: E.ecuting several programs simultaneously is called process $ased multitas)ing

$# .,read !ased multitasing: E.ecuting di%%erent parts o% the same program with the

help o% threads is called 3hread $ased multitas)ing

E.ample 1:

BBcreating and running a thread using e.tends 3hreadimport (avaio45

class 3demo e.tends 3hread

6

pu$lic void run!#

6

%or!int iH5iP1H5i**#6

Systemoutprintln!i#5

try6

3hreadsleep!1HHH#5BB1HHHms1s

<

catch!E.ception e#6

Systemoutprintln!e#5<

<

<<

I?

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class 3hr>6

pu$lic static void main!String args78#throws &OE.ception

63demo o$(new 3demo!#5

3hread tnew 3hread!o$(#5

tstart!#5

<

<

E.ample >:

BBcreating and running a thread using implements Runna$leclass 3heatre implements Runna$le

6

String str53heatre!String str#

6thisstrstr5

<

pu$lic void run!#

6

%or!int i15iP5i**#6

Systemoutprintln!str*9 9*i#5

try6

3hreadsleep!1HHH#5

<catch!&nterruptedE.ception ie#

6

BBSystemoutprintln!ie#5

ieprintStac)3race!#5<

<

<<

class 3hr?

6

pu$lic static void main!String args78#6

3heatre o$(new 3heatre!9cut tic)et9#53heatre o$(1new 3heatre!9see movie9#5

3hread t1new 3hread!o$(#5

3hread t>new 3hread!o$(1#5

t1start!#5t>start!#5

I@

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<<

.,read Snc,roni

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catch!&nterruptedE.ception ie#6

Systemoutprintln!ie#5

<<

<

pu$lic class Multi3hreadDemo6


63hread1 t1new 3hread1!#5

3hread> t>new 3hread>!#5

t1start!#5t>start!#5

<

<

.,read Priorit:

Max Priorit; 1?

Min Priorit

4orm Priorit 1

E.ample:

BB+riority Demo

pu$lic class +riorityDemo e.tends 3hread

6

pu$lic void run!#6

%or!int iH5iP5i**#

6String str3hreadcurrent3hread!#get=ame!#5

Systemoutprintln!str*9:9*i#5

<<


6+riorityDemo pd1new +riorityDemo!#5

+riorityDemo pd>new +riorityDemo!#5

pd1set=ame!9irst9#5 pd>set=ame!9Second9#5

pd>set+riority!MAGb+R&OR&3Z#5BBpd>set+riority!K#5

pd1set+riority!M&=b+R&OR&3Z#5

IF

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pd1start!#5

pd>start!#5

Systemoutprintln!9+riority o% pd1 is 9*pd1get+riority!##5

Systemoutprintln!9+riority o% pd> is 9*pd>get+riority!##5

<<

#pplet: An Applet is a program that comes %rom internet server into a client and gets e.ecuted atclient side and displays the result An applet represents $yte code em$edded in a /3M'

page

Applet $yte code * /3M'

#pplet >ie ccle met,ods:

1) pu!lic void init(): 3his method is used %or initialiing the varia$les" parameters and to create

Components !$utton"images# 3his method is e.ecuted only once at the timeo% applet loaded into memory

2) pu!lic void start(): 3his method will e.ecute when applet gains the %ocus

3) pu!lic void stop():3his method will e.ecute when applet loss the %ocus

&) pu!lic void destro(): 3his method is e.ecuted only once when the applet is terminated %romMemory

E.ample 1:

import (avaawt45

import (avaapplet45B4Papplet code9MyApplet19 widthIHH height@HHQ

PBappletQ4B

pu$lic class MyApplet1 e.tends Applet

6String msg9 95

pu$lic void init!#

6

set0ac)ground!Colorpin)#5setoreground!Coloryellow#5

ont %new ont!9Dialog9"ont0O'D"?H#5setont!%#5

msg*9&nit95

<

pu$lic void start!#6

IK

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msg*9start95<

pu$lic void paint!2raphics g#

6msg*9paint95

gdrawString!msg"1HH"1HH#5

< pu$lic void stop!#

6

msg*9stop95<

pu$lic void destroy!#

6<

<

PhtmlQ

Ph1QMy irst AppletPBh1QP$ody $gcolor9red9Q

Papplet code9MyApplet1class9 width@HH height?HHQPBappletQPB$odyQ

PBhtmlQ

E.ample >:

BB&nsert image into Applet

import (avaapplet45import (avaawt45

B4Papplet code9MyApplet>class9 width@HH height?HHQ

PBappletQ4B pu$lic class MyApplet> e.tends Applet

6

pu$lic void init!#

6< pu$lic void paint!2raphics g#

6

&mage iget&mage!getDocument0ase!#"9O0JEC3gi%9#5

BBmove image %rom le%t to right

%or!int .H5.P1HH5.**#

6gdraw&mage!i"."H"this#5

<BBma)e time delay

try

6

3hreadsleep!1HHH#5<

IX

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catch!&nterruptedE.ception &E#6<

<

<

PhtmlQ

Ph1QMy &magePBh1QP$ody $gcolor9red9Q

Papplet code9MyApplet>class9 width@HH height?HHQ

PBappletQPB$odyQ

PBhtmlQ

E.ample ?:

BBpassing value %rom /3M' to applet

import (avaawt45import (avaappletApplet5

pu$lic class MyApplet? e.tends Applet6

ont %new ont!9Ariel9"ont0O'D">@#5

String msg5

pu$lic void paint!2raphics g#

6gsetont!%#5

gsetColor!Color$lue#5

gdrawString!msg"1H"H#5<

pu$lic void init!#

6msgget+arameter!9para9#5

i%!msgnull#

msg9=ull value returned95

<<

PhtmlQPheadQ

PtitleQMy pagePBtitleQ

PBheadQ

P$ody $gcolor$lueQPh>Q3his page shows use o% AppletPBh>Q

PpQPapplet code9MyApplet?class9 width@HH height1HHQ

Pparam namepara value9+assing value %rom /3M'9Q

PBappletQ

PB$odyQPBhtmlQ

FH

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E.ample @:

BBDraw graphicsimport (avaawt2raphics5

import (avaawtont5

import (avaawtColor5import (avaappletApplet5

pu$lic class MyApplet@ e.tends Applet

6 pu$lic void paint!2raphics g#

6

ont %new ont!9Courier9"ont0O'D"1I#5

Color cnew Color!>HH">?">#5gdraw'ine!1H"1"1H"IH#5

gdraw'ine!1H"1"IH"1H#5

gdrawRect!1H"1H"H"H#5gsetont!%#5

gsetColor!c#5gdrawString!9/ave a nice Day;9"11H"H#5

<

<

PhtmlQPheadQ

PtitleQMy pagePBtitleQ

PBheadQP$ody $gcolorredQ

Ph>Q3his page shows use o% 2raphicsPBh>Q

PpQPapplet code9MyApplet@class9 width@HH height1HHQPBappletQ

PB$odyQ

PBhtmlQ

F1

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F?

Date post:	06-Jul-2018
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