Java.pptx

JAVA

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What is JAVA  Java

is a programming language and a platform.

 Java

is a high level, robust, secured and object-oriented

programming language.  Java

has its own runtime environment (JRE) and

Application Programming Interface (API).

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APPLICATIONS OF JAVA  Desktop Applications

such as acrobat reader, media

player, antivirus etc.  Web Applications such as irctc.co.in, javatpoint.com etc.  Enterprise Applications such as banking applications.  Mobile  Embedded System  Smart Card  Robotics  Games etc.

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TYPES OF JAVA APPLICATIONS  Standalone

Application, desktop application or window-based application: Application installed on every machine such as media player, antivirus, etc.  Web Application: An application that runs on the server side and creates dynamic page.  Enterprise Application: An application that is distributed in nature, such as banking applications etc.  Mobile Application: An application that is created for mobile devices.

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FEATURES  Simple  Object-Oriented  Platform

independent

 Secured  Robust

 Architecture

neutral

 Portable  Dynamic  Interpreted

 High

Performance  Multithreaded  Distributed

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C++ vs JAVA C++

Java

C++ is platform-dependent.

Java is platform-independent.

C++ is mainly used for system programming.

Java is mainly used for application programming. It is widely used in window, web-based, enterprise and mobile applications.

C++ supports goto statement.

Java doesn't support goto statement.

C++ supports multiple inheritance. Java doesn't support multiple inheritance through class. It can be achieved by interfaces in java. C++ supports operator overloading.

Java doesn't support operator overloading.

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Contd… C++

Java

C++ supports pointers. You can write pointer program in C++.

Java supports pointer internally. But you can't write the pointer program in java. It means java has restricted pointer support in java.

C++ uses compiler only.

Java uses compiler and interpreter both.

C++ supports both call by value and Java supports call by value only. call by reference. There is no call by reference in java. C++ supports structures and unions.

Java doesn't support structures and unions.

C++ doesn't have built-in support for threads. It relies on third-party libraries for thread support.

Java has built-in thread support.

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Contd… C++

Java

C++ doesn't support documentation comment.

Java supports documentation comment to create documentation for java source code.

C++ supports virtual keyword so that we can decide whether or not override a function.

Java has no virtual keyword. We can override all non-static methods by default. In other words, non-static methods are virtual by default.

C++ doesn't support >>> operator.

Java supports unsigned right shift >>> operator that fills zero at the top for the negative numbers. For positive numbers, it works same like >> operator.

C++ creates a new inheritance tree always.

Java uses single inheritance tree always because all classes are the child of Object class in java. Object class is the root of inheritance tree in java.

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DEFINITIONS   

 

 

class keyword is used to declare a class in java. public keyword is an access modifier which represents visibility, it means it is visible to all. static is a keyword, if we declare any method as static, it is known as static method. The core advantage of static method is that there is no need to create object to invoke the static method. The main method is executed by the JVM, so it doesn't require to create object to invoke the main method. So it saves memory. void is the return type of the method, it means it doesn't return any value. main represents startup of the program. String[] args is used for command line argument. System.out.println() is used to print statement.

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HELLO PROGRAM class Simple{ public static void main(String args[]){ System.out.println("Hello Java"); System.out.println("Welcome to the world of Java programming"); } } Output: Hello Java Welcome to the world of Java programming

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COMPILE TIME  At

the compile time, java file is compiled by Java Compiler (It does not interact with OS) and converts the java code into bytecode.

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RUNTIME Classloader: It is the subsystem of JVM that is used to load class files. Bytecode Verifier: It checks the code fragments for illegal code that can violate access right to objects. Interpreter: It reads bytecode stream and execute the instructions.

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MULTIPLE CLASSES IN JAVA SOURCE FILE

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JAVA VIRTUAL MACHINE (JVM)    



JVM is an abstract machine. It is a specification that provides runtime environment in which java bytecode can be executed. JVMs are available for many hardware and software platforms. JVM, JRE and JDK are platform dependent because configuration of each OS differs. But, Java is platform independent. The JVM performs following main tasks: 

  

Loads code Verifies code Executes code Provides runtime environment

15 JVM provides definitions for the: 

Memory area



Class file format



Register set



Garbage-collected heap



Fatal error reporting etc.

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INTERNAL ARCHITECTURE OF JVM

17 Classloader

It is a subsystem of JVM that is used to load class files.

Class (Method) Area It stores per-class structures such as the runtime constant pool, field and method data, the code for methods. Heap

It is the runtime data area in which objects are allocated.

Stack

Java Stack stores frames. It holds local variables and partial results, and plays a part in method invocation and return. Each thread has a private JVM stack, created at the same time as thread. A new frame is created each time a method is invoked. A frame is destroyed when its method invocation completes.

18 Program counter It contains the address of the Java virtual machine register instruction currently being executed.

Native method stack

It contains all the native methods used in the application.

Execution engine

1) A virtual processor

2) Interpreter: Read bytecode stream and execute the instructions. 3) Just-In-Time(JIT) compiler: It is used to improve the performance. JIT compiles parts of the byte code that have similar functionality at the same time. It reduces the amount of time needed for compilation. Here the term ?compiler? refers to a translator from the instruction set of a JVM to the instruction set of a specific CPU.

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JAVA RUNTIME ENVIRONMENT (JRE)   



JRE is used to provide runtime environment. It is the implementation of JVM. It physically exists. It contains set of libraries + other files that JVM uses at runtime. Implementation of JVMs are also actively released by other companies besides Sun Micro Systems.

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JAVA DEVELOPMENT KIT (JDK) 



JDK physically exists. It contains JRE + development tools.

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VARIABLES  Variable

is name of reserved area allocated in memory.  In other words, it is a name of memory location.  It is a combination of "vary + able" that means its value can be changed.

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TYPES OF VARIABLE Local

• It is declared inside the method.

Instance

• It is declared inside the class but outside the method. It is not declared as static.

Static

• It is declared as static. It cannot be local.

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EXAMPLE class A{ int data=50; //instance variable static int m=100; //static variable void method(){ int n=90; //local variable } }//end of class

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DATA TYPES  Data

types represent the different values to be stored in the variable.

25 Data Type

Default Value

Default size

boolean

false

1 bit

char

'\u0000'

2 byte

byte

0

1 byte

short

0

2 byte

int

0

4 byte

long

0L

8 byte

float

0.0f

4 byte

double

0.0d

8 byte

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UNICODE SYSTEM Unicode is a universal international standard character encoding that is capable of representing most of the world's written languages. In unicode, character holds 2 byte, so java also uses 2 byte for characters. lowest value:\u0000 highest value:\uFFFF

27 Operators

Precedence

postfix

expr++ expr--

unary

++expr --expr +expr -expr ~ !

multiplicative

*/%

additive

+-

shift

<< >> >>>

relational

< > <= >= instanceof

equality

== !=

bitwise AND

&

bitwise exclusive OR ^ bitwise inclusive OR | logical AND

&&

logical OR

||

ternary

?:

assignment

= += -= *= /= %= &= ^= |= <<= >>= >>>=

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IF-ELSE STATEMENT  The

Java if statement is used to test the condition. It

checks Boolean condition: true or false.  There  if

are various types of if statement in java.

statement

 if-else

statement

 nested

if statement

 if-else-if

ladder

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JAVA “IF” STATEMENT The Java if statement tests the condition. It executes the if block if condition is true. Syntax: if(condition){ //code to be executed }

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EXAMPLE public static void main(String[] args) { int age=20; if(age>18){ System.out.print("Age is greater than 18"); } }

Output: Age is greater than 18

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IF-ELSE STATEMENT The Java if-else statement also tests the condition. It executes the if block if condition is true otherwise else block is executed.

Syntax: if(condition){ //code if condition is true }else { //code if condition is false }

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EXAMPLE public static void main(String[] args) { int number=13; if(number%2==0){ System.out.println("even number"); } else { System.out.println("odd number"); } } Output: Odd number

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IF-ELSE-IF LADDER STATEMENT 

The if-else-if ladder statement executes one condition from multiple statements.

Syntax: if(condition1){ //code to be executed if condition1 is true }else if(condition2){ //code to be executed if condition2 is true } ... else{ //code to be executed if all the conditions are false }

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35 public static void main(String[] args) { int marks=65; if(marks<50){ System.out.println("fail");} else if(marks>=50 && marks<60){ System.out.println("D grade");} else if(marks>=60 && marks<70){ System.out.println("C grade");} else if(marks>=70 && marks<80){ System.out.println("B grade");} else if(marks>=80 && marks<90){ System.out.println("A grade");} else if(marks>=90 && marks<100){ System.out.println("A+ grade");}else{ System.out.println("Invalid!"); }}}

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SWITCH STATEMENT The Java switch statement executes one statement from multiple conditions. It is like if-else-if ladder statement. Syntax: switch(expression){ case value1: //code to be executed; break; //optional case value2: //code to be executed; break; //optional ...... default: code to be executed if all cases are not matched; }

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EXAMPLE public static void main(String[] args) { int number=20; switch(number){ case 10: System.out.println("10");break; case 20: System.out.println("20");break; case 30: System.out.println("30");break; default:System.out.println("Not in 10, 20 or 30"); } } Output 20

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SWITCH STATEMENT IS FALLTHROUGH public static void main(String[] args) { int number=20; switch(number){ case 10: System.out.println("10"); case 20: System.out.println("20"); case 30: System.out.println("30"); default:System.out.println("Not in 10, 20 or 30"); } } Output 20 30 Not in 10, 20 or 30

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FOR LOOP  The

Java for loop is used to iterate a part of the program

several times. If the number of iteration is fixed, it is recommended to use for loop.  There

are three types of for loop in java.

 Simple

For Loop

 For-each  Labeled

or Enhanced For Loop

For Loop

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SIMPLE FOR LOOP The simple for loop is same as C/C++. We can initialize variable, check condition and increment/decrement value.

Syntax: for(initialization;condition ;incr/decr) { //code to be executed }

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EXAMPLE public static void main(String[] args) { for(int i=1;i<=10;i++){ System.out.println(i); } } Output: 1 : : 10

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JAVA FOR-EACH LOOP The for-each loop is used to traverse array or collection in java. It is easier to use than simple for loop because we don't need to increment value and use subscript notation. Syntax: for(Type var:array) { //code to be executed }

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EXAMPLE public static void main(String[] args) { int arr[]={12,23,44,56,78}; for(int i:arr){ System.out.println(i); } } Output: 12 23 44 56 78

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JAVA LABELED FOR LOOP  Normally,

break and continue keywords breaks/continues the inner most for loop only.

Syntax: labelname: for(initialization;condition;incr/decr) { //code to be executed }

46 public static void main(String[] args) { aa: for(int i=1;i<=3;i++){ bb: for(int j=1;j<=3;j++){ if(i==2&&j==2){ break aa; } System.out.println(i+" "+j);} }}} Output: 11 12 13 21

47 public static void main(String[] args) { aa:

for(int i=1;i<=3;i++){ bb: for(int j=1;j<=3;j++){ if(i==2&&j==2){ break bb; } System.out.println(i+" "+j); } } }

Output: 11 12 13 21 31 32 33

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INFINITIVE FOR LOOP  If

you use two semicolons ;; in the for loop, it will be infinitive for loop.

Syntax: for(;;) { //code to be executed }

49 public static void main(String[] args) { for(;;) { System.out.println("infinitive loop"); } } Output: infinitive loop infinitive loop infinitive loop ctrl+c

50

WHILE LOOP  The

Java while loop is used to iterate a part of the program several times.  If the number of iteration is not fixed, it is recommended to use while loop. Syntax: while(condition) { //code to be executed }

51 public static void main(String[] args) { int i=1; while(i<=10){ System.out.println(i); i++; } } Output: 1 2 : 10

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INFINITIVE WHILE LOOP  If

you pass true in the while loop, it will be infinitive while loop.

Syntax: while(true) { //code to be executed }

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DO-WHILE LOOP  The

Java do-while loop is used to iterate a part of the program several times. If the number of iteration is not fixed and you must have to execute the loop at least once, it is recommended to use do-while loop.  The Java do-while loop is executed at least once because condition is checked after loop body. Syntax: do{ //code to be executed }while(condition);

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55 public static void main(String[] args) { int i=1; do{ System.out.println(i); i++; }while(i<=10); } } Output: 1 2 : : 10

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INFINITIVE DO-WHILE LOOP  If

you pass true in the do-while loop, it will be infinitive do-while loop.

Syntax: do { //code to be executed } while(true);

57 public static void main(String[] args) { do{ System.out.println("infinitive do while loop"); }while(true); } } Output: infinitive do while loop infinitive do while loop infinitive do while loop ctrl+c

58

BREAK STATEMENT  The

Java break is used to break loop or switch statement.  It breaks the current flow of the program at specified condition.  In case of inner loop, it breaks only inner loop. Syntax: jump-statement; break;

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BREAK STATEMENT WITH LOOP public static void main(String[] args) { for(int i=1;i<=10;i++){ if(i==5){ break; } System.out.println(i); } } Output: 1 2 3 4

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BREAK STATEMENT WITH INNER LOOP public static void main(String[] args) { for(int i=1;i<=3;i++){ for(int j=1;j<=3;j++){ if(i==2&&j==2){ break; } System.out.println(i+" "+j); } } }

Output 11 12 13 21 31 32 33

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CONTINUE STATEMENT  The

Java continue statement is used to continue loop.  It continues the current flow of the program and skips the remaining code at specified condition.  In case of inner loop, it continues only inner loop. Syntax: jump-statement; continue;

62 public static void main(String[] args ){ for(int i=1;i<=10;i++){ if(i==5){ continue; } System.out.println(i); } }

Output 1 2 3 4 6 7 8 9 10

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CONTINUE STATEMENT WITH INNER LOOP 

It continues inner loop only if you use continue statement inside the inner loop.

public static void main(String[] args) { for(int i=1;i<=3;i++){ for(int j=1;j<=3;j++){ if(i==2&&j==2){ continue; } System.out.println(i+" "+j); } } }

Output 11 12 13 21 23 31 32 33

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COMMENTS  The

java comments are statements that are not executed by the compiler and interpreter.  The comments can be used to provide information or explanation about the variable, method, class or any statement.  It can also be used to hide program code for specific time.

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TYPES OF COMMENTS Single line comment

Comments

Multi line comment

Documentation comment

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SINGLE LINE COMMENT  The

single line comment is used to comment only one

line. Syntax: //This is a single line comment Example: public static void main(String[] args) { int i=10;//Here, i is a variable System.out.println(i); } Output: 10

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MULTI LINE COMMENT  The

multi line comment is used to comment multiple lines of code. Example: public static void main(String[] args) { /* Let's declare and print variable in java. */ int i=10; System.out.println(i); } Output: 10

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DOCUMENTATION COMMENT  The

documentation comment is used to create documentation API. To create documentation API, you need to use javadoc tool.

public class Calculator { /** The add() method returns addition of given numbers.*/ public static int add(int a, int b){return a+b;} /** The sub() method returns subtraction of given numbers.*/ public static int sub(int a, int b){return a-b;} }

69 Compile it by javac tool: javac Calculator.java Create Documentation API by javadoc tool: javadoc Calculator.java Now, there will be HTML files created for your Calculator class in the current directory. Open the HTML files and see the explanation of Calculator class provided through documentation comment.

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JAVA PROGRAMS

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FIBONACCI SERIES public static void main(String args[]) { int n1=0,n2=1,n3,i,count=10; System.out.print(n1+" "+n2); //printing 0 and 1 for(i=2;i
Output: 0 1 1 2 3 5 8 13 21 34

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PRIME NUMBER public static void main(String args[]){ int i,m=0,flag=0; int n=17;//it is the number to be checked m=n/2; for(i=2;i<=m;i++){ if(n%i==0){ System.out.println("Number is not prime"); flag=1; break; Output: } Number is prime } if(flag==0) System.out.println("Number is prime"); }

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PALINDROME NUMBER public static void main(String args[]){ int r,sum=0,temp; int n=454;//It is the number variable to be checked for palindrome temp=n; while(n>0){ r=n%10; //getting remainder sum=(sum*10)+r; n=n/10; } if(temp==sum) Output: System.out.println("palindrome number "); else Palindrome number System.out.println("not palindrome"); }

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FACTORIAL NUMBER public static void main(String args[]){ int i,fact=1; int number=5; //It is the number to calculate factorial for(i=1;i<=number;i++){ fact=fact*i; } System.out.println("Factorial of "+number+" is: "+fact); } Output: Factorial of 5 is: 120

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FACTORIAL PROGRAM USING RECURSION static int factorial(int n){ if (n == 0) return 1; else return(n * factorial(n-1)); } public static void main(String args[]){ int i,fact=1; int number=4;//It is the number to calculate factorial fact = factorial(number); System.out.println("Factorial of "+number+" is: "+fact); } Output: Factorial of 4 is: 24

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ARMSTRONG NUMBER public static void main(String[] args) { int c=0,a,temp; int n=153;//It is the number to check armstrong temp=n; while(n>0){ a=n%10; n=n/10; c=c+(a*a*a); } if(temp==c) System.out.println("armstrong number"); else System.out.println("Not armstrong number"); } Output: Armstrong number

77

BUBBLE SORT  In

bubble sort algorithm, array is traversed from first element to last element.  Here, current element is compared with the next element.  If current element is greater than the next element, it is swapped.

78 public class BubbleSortExample { static void bubbleSort(int[] arr) { int n = arr.length; int temp = 0; for(int i=0; i < n; i++){ for(int j=1; j < (n-i); j++){ if(arr[j-1] > arr[j]){ //swap elements temp = arr[j-1]; arr[j-1] = arr[j]; arr[j] = temp; } } } }

79 public static void main(String[] args) { int arr[] ={3,60,35,2,45,320,5}; System.out.println("Array Before Bubble Sort"); for(int i=0; i < arr.length; i++){ System.out.print(arr[i] + " "); } System.out.println(); bubbleSort(arr);//sorting array elements using bubble sort System.out.println("Array After Bubble Sort"); for(int i=0; i < arr.length; i++){ System.out.print(arr[i] + " "); } } }

Output: Array Before Bubble Sort 3 60 35 2 45 320 5 Array After Bubble Sort 2 3 5 35 45 60 320

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SELECTION SORT 



In selection sort algorithm, we search for the lowest element and arrange it to the proper location. We swap the current element with the next lowest number.

81 public class SelectionSortExample { public static void selectionSort(int[] arr){ for (int i = 0; i < arr.length - 1; i++) { int index = i; for (int j = i + 1; j < arr.length; j++){ if (arr[j] < arr[index]){ index = j;//searching for lowest index } } int smallerNumber = arr[index]; arr[index] = arr[i]; arr[i] = smallerNumber; } }

82 public static void main(String a[]){ int[] arr1 = {9,14,3,2,43,11,58,22}; System.out.println("Before Selection Sort"); for(int i:arr1){ System.out.print(i+" "); } System.out.println(); selectionSort(arr1);//sorting array using selection sort System.out.println("After Selection Sort"); for(int i:arr1){ System.out.print(i+" "); } } }

Output: Before Selection Sort 9 14 3 2 43 11 58 22

After Selection Sort 2 3 9 11 14 22 43 58

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INSERTION SORT  Insertion

is good for small elements only because it requires more time for sorting large number of elements.

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INSERTION SORT ALGORITHM public static void insertionSort(int array[]) { int n = array.length; for (int j = 1; j < n; j++) { int key = array[j]; int i = j-1; while ( (i > -1) && ( array [i] > key ) ) { array [i+1] = array [i]; i--; } array[i+1] = key; } }

85 public static void main(String a[]){ int[] arr1 = {9,14,3,2,43,11,58,22}; System.out.println("Before Insertion Sort"); for(int i:arr1){ System.out.print(i+" "); } System.out.println(); insertionSort(arr1); //sorting array using insertion sort System.out.println("After Insertion Sort"); for(int i:arr1){ System.out.print(i+" "); } }

Output:

Before Insertion Sort 9 14 3 2 43 11 58 22 After Insertion Sort 2 3 9 11 14 22 43 58