Array List and Custom Class in Java

 As salamo alaikum wa rahmatullah

package collections.demo;

import java.util.ArrayList;

class Employee{

int emp_no;

String empname;

double Salary;

}

public class CustomClassArrayList {

public static void main(String[] args) {

// TODO Auto-generated method stub

ArrayList<Employee> aListEmp=new ArrayList<Employee>();

Employee e=new Employee();

e.emp_no=101;

e.empname="Mohammad Shahnawaz";

e.Salary=1200.99;

aListEmp.add(e);

e=new Employee();

e.emp_no=102;

e.empname="Arham Hanan Zamman";

e.Salary=1200.99;

aListEmp.add(e);

e=new Employee();

e.emp_no=103;

e.empname="Khadija Zamman";

e.Salary=1200.99;

aListEmp.add(e);

for(Employee e1: aListEmp) {

System.out.println("Employee no :- "+e1.emp_no);

System.out.println("Employee name :- "+e1.empname);

System.out.println("Employee salary :- "+e1.Salary);

}

}

}

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Example of Array List Iterator in Java

 As salamo alaikum wa rahmatullah

Example of Array List and Fetch Element using Iterator in Java
package collections.demo;

import java.util.ArrayList;
import java.util.Random;
import java.util.*;

public class ArrayListIterationDemo {

public static void main(String[] args) {
// TODO Auto-generated method stub
ArrayList<Integer> iList=new ArrayList<Integer>();
for(int i=0; i<=10;i++) {
Random rand=new Random();
int a=rand.nextInt(1000);
iList.add(a);
}
Iterator itr=iList.iterator();
System.out.println("Iterate usin for loop");
for( ; itr.hasNext() ; ) {
System.out.println(itr.next());
}
itr=iList.iterator();
System.out.println("Iterate usin while loop");
while(itr.hasNext()) {
System.out.println(itr.next());
}

}

}

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Example of Linked List in Java

 As salamo alaikum wa rahmatullah

package collections.demo;

import java.util.LinkedList;

import java.util.Scanner;

public class LinkedListDemo {

public static void main(String[] args) {

// TODO Auto-generated method stub

LinkedList<String> lList=new LinkedList<String>();

Scanner sc=new Scanner(System.in);

for(int i=0;i<=5;i++) {

System.out.println("Enter the string for Linked List");

String name=sc.nextLine();

lList.add(name);

}

System.out.println(lList);

// iterating data

for(int j=0; j<lList.size();j++) {

System.out.println("Element of Linked List - "+lList.get(j));

}

}

}

Jazak allah khair

Example of Array List in Java

 As salamo alaikum wa rahmatullah

package collections.demo;

import java.util.ArrayList;

import java.util.Scanner;

public class ArrayListDemo {

public static void main(String[] args) {

// TODO Auto-generated method stub

ArrayList<String> aList=new ArrayList<String>();

Scanner sc=new Scanner(System.in);

for(int i=0; i<=5;i++) {

System.out.println("Enter the string for Array List");

String str=sc.nextLine();

aList.add(str);

}

// printing element

System.out.println("Element is Array List"+aList);

// fetching element using for loop

for(int i=0; i<aList.size(); i++) {

System.out.println("Element : -"+aList.get(i));

}

}

}

Jazak allah khair

Example of Array, Vector and Hash Table in Java

 As salamo alaikum wa rahmatullah

Example of Array, Vector and Hash Table

package collections.demo;

import java.util.Hashtable;

import java.util.Vector;

public class CollectionDemo {

public static void main(String[] args) {

// TODO Auto-generated method stub

int arr[]=new int[] {1,2,3,4,5,6};

Vector<Integer> v=new Vector();

Hashtable <Integer,String> hTable=new Hashtable();

// Adding element into the vector

v.add(1);

v.add(2);

v.add(3);

System.out.println(v);

v.set(0, 3);

System.out.println(v);

// Adding element into the HashTable

hTable.put(1, "Selenium");

hTable.put(2, "Java");

hTable.put(3, "OOSPS");

hTable.put(4, "Selenium");

System.out.println(hTable);

String s=hTable.values().toString();

System.out.println("Values of Hash Table :- "+s);

// Array instance creation requires []

// While vector and HashTable require ()

// Vector element insertion required addElement()

// but HashTable element insertion require put()

// Accessing the first element of the 

// array, vector and HashTable

System.out.println(arr[0]);

System.out.println(v.elementAt(0));

System.out.println(hTable.get(1));

}

}

--

Output

[1, 2, 3]

[3, 2, 3]

{4=Selenium, 3=OOSPS, 2=Java, 1=Selenium}

Values of Hash Table :- [Selenium, OOSPS, Java, Selenium]

1

3

Selenium

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Count of Character into the String

 As salamo alaikum wa rahmatullah

package examples;

import java.util.Scanner;

public class CountOccurenceOfCharacterIntoString {

public static void main(String[] args) {

// TODO Auto-generated method stub

Scanner sc=new Scanner(System.in);

System.out.println("Enter the String");

String inputStr=sc.nextLine();

System.out.println("Enter a character which has to be counted into given string");

String cntStr=sc.nextLine();

int total_len=inputStr.length();

int len_inoccured_after_replace=inputStr.replace(cntStr, "").length();

int actual_len=total_len-len_inoccured_after_replace;

System.out.println("Count is"+actual_len);

}

}

Jazak Allah Khair

Palindrome String in Java

As salamo alaikum wa rahmatullah

package examples;

import java.util.Scanner;

public class PalineDromeString {

public static void main(String[] args) {

// TODO Auto-generated method stub

Scanner sc=new Scanner(System.in);

System.out.println("Enter String to check palindrome");

String str=sc.nextLine();

// Using the string buffer

StringBuilder sb=new StringBuilder();

sb.append(str);

StringBuilder sb1=sb.reverse();

System.out.println("Entered string is "+str);

System.out.println("Reverse string is "+sb1);

if(str.equals(sb1.toString()))

{

System.out.println("Entered string is palindrome");

}

else

{

System.out.println("Entered string is not palindrome");

}

}

}

Jazak Allah Khair

Palindrome in Java

As salamo alaikum wa rahmatullah

package examples;

import java.util.Scanner;

public class PalindromNumber {

public static void main(String[] args) {

// TODO Auto-generated method stub

Scanner sc=new Scanner(System.in);

System.out.println("Enter a number");

int num=sc.nextInt();

int rev=0;

int org_num=num;

while(num!=0) {

rev=rev*10+num%10;

num=num/10;

}

if (org_num==rev) {

System.out.println("Entered number is palindrome");

}

else

{

System.out.println("Entered number is not palindrome");

}

}

}

Jazak allah khair 

Three Different Way of Reversing a String in Java

 As salamo alaikum wa rahmatullah

package examples;

import java.util.Scanner;

public class ReverseString {

public static void main(String[] args) {

// TODO Auto-generated method stub

Scanner sc=new Scanner(System.in);

System.out.println("Enter a String");

String str=sc.nextLine();

int len=str.length();

String rev="";

for(int j=len-1;j>=0;j--) {

rev=rev+str.charAt(j);

}

System.out.println("Reverse string is : -"+ rev);

rev="";

char a[]=str.toCharArray();

int len1=a.length;

for(int k=len1-1;k>=0;k--)

{

rev=rev+a[k];

}

System.out.println("Again the reverse :- "+rev);

// Reverse string using StringBuffer class

StringBuffer sbf=new StringBuffer(str);

StringBuffer rev2=sbf.reverse();

System.out.println("Again the reverse :- "+rev2);

}

}

Jazak Allah Khair

Three Different Way of Reversing Number in Java

 As salamo alaikum wa rahmatullah

3 different way to reverse a number

package examples;

import java.util.Scanner;

public class ReverseNumber {

public static void main(String[] args) {

// TODO Auto-generated method stub

Scanner sc=new Scanner(System.in);

System.out.println("Enter number to be reversed");

int num=sc.nextInt();

// Logic - 01

int rev=0;

while(num!=0) {

rev=rev*10 + num%10;

num=num/10;

}

System.out.println(rev);

// Logic - 02

System.out.println("Enter a number again");

num=sc.nextInt();

StringBuffer rev1;

StringBuffer sb=new StringBuffer(String.valueOf(num));

rev1=sb.reverse();

System.out.println("Reverse number"+rev1);

// Logic - 03 

StringBuilder rev2;

StringBuilder sbl=new StringBuilder();

sbl.append(num);

rev2=sbl.reverse();

System.out.println("Reverse number"+rev2);

}

}

Zajak allah khair

Multiple Inheritance

 package practice.test;

interface Ones {

void print_test();

}

interface Twos{

public void print_test1();

}

interface Three extends Ones,Twos{

void print_test();

}

class child implements Three

{

@Override

public void print_test() {

System.out.println("Test overides - Test Methods");

}

public void print_test1() {

System.out.println("Inside Test1");

}

}

 class Main_01

{

public static void main(String[] arg) {

child c=new child();

c.print_test();

c.print_test1();

c.print_test();

}

}

Inheritance concept

 package practice.test;

class One {

public void print_greek() {

System.out.println("Geeks");

}

}

class Two extends One{

public void print_for() {

System.out.println("For");

}

}

class Main

{

public static void main(String[] args) {

Two t=new Two();

t.print_greek();

t.print_for();

t.print_greek();

}

}

Inheritance concept

 Implementation of Inheritence

package practice.test;

public class Bicycle {

public int gear;

public int speed;

// Constructor

public Bicycle(int gear,int speed) {

this.gear=gear;

this.speed=speed;

}

// the Bycycle class has three methods

public void applyBreak(int decrement) {

speed-=decrement;

}

public void speedUp(int increment) {

speed+=increment;

}

public String toString() {

return ("No of gears are "+gear+"\n"+"speed of bicycle is"+speed);

}

}

// derived class

class MountainBike extends Bicycle

{

public int seatHeight;

public MountainBike(int gear,int speed,int seatHeight) {

super(gear,speed);

this.seatHeight=seatHeight;

}

// method

public void setSeatHeight(int newValue) {

seatHeight=newValue;

}

@Override

public String toString() {

return (super.toString() + "\n height is \t"+seatHeight);

}

}

package practice.test;

public class Tests {

public static void main(String[] args) {

// TODO Auto-generated method stub

MountainBike mBike=new MountainBike(3,100, 25);

System.out.println(mBike.toString());

}

}

-- Output

No of gears are 3

speed of bicycle is100

 height is 25

Implementation of Interface

 Interface Implementation an Interface defined in class

example here under
package practice.test;

public class IntefaceInsideClass {
interface Viechle{
public int getNoOfWheels();
}
}
Implementation of Interface
package practice.test;

public class Bus implements IntefaceInsideClass.Viechle{
public int getNoOfWheels() {
return 6;
}
}

package practice.test;

public class Cars implements IntefaceInsideClass.Viechle{
public int getNoOfWheels() {
return 4;
}

}

package practice.test;

public class Bikes implements IntefaceInsideClass.Viechle{
public int getNoOfWheels() {
return 2;
}

}


Finaly call for executions
package practice.test;

public class TestClass1 {

public static void main(String[] args) {
// TODO Auto-generated method stub
Bus b = new Bus();
System.out.println("No of Wheels for bus\t"+b.getNoOfWheels());
Cars c=new Cars();
System.out.println("No of Wheels for cars\t"+c.getNoOfWheels());
Bikes b1=new Bikes();
System.out.println("No of Wheels for bike\t"+b1.getNoOfWheels());

}

}

Output
-------------
No of Wheels for bus 6
No of Wheels for cars 4
No of Wheels for bike 2