Java Program to find even numbers and odd numbers

It is very basic program to start with programming.You might be knowing that even numbers are those numbers which are divisible by 2 and odd numbers are those which are not.

So lets see  implementation in the example given below:

 import java.util.Scanner;  
 /**  
  *   
  */  
 /**  
  * @author Dixit  
  *  
  */  
 public class EvenOddExample {  
      /**  
       * @param args  
       */  
      public static void main(String[] args) {  
              int x;  
              System.out.println("Enter number to check if it is odd or even ");  
              Scanner in = new Scanner(System.in);  
              x = in.nextInt();  
              if ( x % 2 == 0 )  
                System.out.println("You entered an even number.");  
              else  
                System.out.println("You entered an odd number.");  
      }  
 }  

Enjoy Reading.

How to iterate or traverse ArrayList in Java

How to iterate or traverse ArrayList in Java


There are many ways to traverse over ArrayList.For ex: simple for loop,for-each loop and Iterator.

Lets have a look at the implementation of all different ways of traversing ArrayList.

1:  import java.util.ArrayList;  
2:  import java.util.Iterator;  
3:  /**  
4:   *   
5:   */  
6:  /**  
7:   * @author   
8:   *  
9:   */  
10:  public class ArrayListTraverseExample {  
11:       /**  
12:        * @param args  
13:        */  
14:       public static void main(String[] args) {  
15:      ArrayList<String> listCompanies = new ArrayList<String>();  
16:      listCompanies.add("Infosys");  
17:      listCompanies.add("TCS");  
18:      listCompanies.add("Cognizant");  
19:      listCompanies.add("Google");  
20:      System.out.println("Size of ArrayList : " + listCompanies.size());  
21:      System.out.println("\n*******Traversing ArrayList using for-each loop*******");  
22:      for(String company: listCompanies){  
23:        //print all elements from ArrayList one by one.  
24:        System.out.println("List of Companies are:"+company);  
25:      }  
26:      System.out.println("\n*******Traversing ArrayList using Iterator*******");  
27:      Iterator<String> itr = listCompanies.iterator();  
28:      while(itr.hasNext()){  
29:            System.out.println("List of Companies are:"+itr.next());  
30:      }  
31:      //You can also Loop over ArrayList using traditional for loop  
32:      System.out.println("\n*******Traversing ArrayList using simple for loop*******");  
33:      for(int i =0; i<listCompanies.size(); i++){  
34:          System.out.println("List of Companies are:"+listCompanies.get(i));  
35:      }  
36:       }  
37:  }  

Output:

Size of ArrayList : 4

*******Traversing ArrayList using for-each loop*******
List of Companies are:Infosys
List of Companies are:TCS
List of Companies are:Cognizant
List of Companies are:Google

*******Traversing ArrayList using Iterator*******
List of Companies are:Infosys
List of Companies are:TCS
List of Companies are:Cognizant
List of Companies are:Google

*******Traversing ArrayList using simple for loop*******
List of Companies are:Infosys
List of Companies are:TCS
List of Companies are:Cognizant
List of Companies are:Google

Please go through the program properly.Enjoy Reading.

Difference between TreeSet and TressMap

TreeSet and TreeMap are two different Collection class in java.TreeSet implements Set interface whereas TressMap impements Map interface.


                                                     TreeSet Vs TreeMap

	TreeSet	TreeMap
Implementation	It implements Set interface.	It implements Map interface.
Storing Objects	TressSet stores only one objects.	TreeMap stores two objects i.e.key and value.
Duplicates	TreeSet does not allow duplicates value.	TreeMap allows duplicate values.
Specific Implementation	It implements NavigableSet.	It implements NavigableMap.

Study Well.Enjoy Reading.

Difference between ArrayList and HashMap

Both ArrayList and HashMap belongs to different Collection class in java.Both of them are used to store objects but their internal working is totally different


.                                              ArrayList Vs HashMap

	ArrayList	HashMap
Implementation	ArrayList implements List interface.	HashMap implements Map interface.
Storage of Objects	ArrayList only stores one object.	HashMap stores tow object one is key and other is value.
Equals and HashCode	ArrayList does not have to implements these methods.	HashMap must implement equals and hashcode method properly.
Order of Insertion	ArrayList maintains order of insertion.	HashMap does not maintains order of insertion.

Happy Reading.Study Well.

Java Program to Find IP Address of the Machine

                    Java Program to find IP Address of the Machine

import java.net.InetAddress;
import java.net.UnknownHostException;


public class FindIpAddress {

  /**
   * @param args
   */
  public static void main(String[] args) {
    
     
              InetAddress myIp = null;
        try {
          myIp = InetAddress.getLocalHost();
        } catch (UnknownHostException e) {
          System.out.println("Exception caught ="+e.getMessage());
        }
              System.out.println("IP of my system is := "+myIp.getHostAddress());
       
  }

}

Enjoy Reading.

Java Program to Print Prime Numbers

                                  Java Program to Print Prime Numbers

This java program prints prime numbers between the input value provided by the user. The smallest prime number starts with 2.

1:  import java.util.Scanner;  
2:  public class Prime {  
3:       /**  
4:        * @param args  
5:        */  
6:       public static void main(String[] args) {  
7:            int iNumber,iRemainderValue;  
8:            //Scanner class used for I/O operations  
9:            Scanner scanner=new Scanner(System.in);  
10:            System.out.println("Enter the number till which you want to generate prime numbers:");  
11:            iNumber=scanner.nextInt();  
12:            //outer loop iterates till iNumber value   
13:            for(int i=2;i<iNumber;i++)  
14:            {  
15:                 iRemainderValue=0;  
16:                 //inner loop checks if value of i is divisible by j values and sets the   
17:                 //iRemainderValue value accordingly.  
18:                 for(int j=2;j<i;j++)  
19:                 {  
20:                      if(i%j==0)  
21:                           iRemainderValue=1;  
22:                 }  
23:                 if(iRemainderValue==0)  
24:                 {  
25:                      System.out.print(i +" ");  
26:                 }  
27:            }  
28:       }  
29:  }  

Enjoy Reading.

Difference between ArrayList and Vector

Difference between ArrayList and Vector comes under Core Java interview questions.It is the most basic questions asked to check the interviewee basic knowledge of Collection before going deep in Collection.


                                                         ArrayList Vs Vector

	ArrayList	Vector
Synchronization	ArrayList in not synchronized means it is not suitable for multi-threaded environment.	Vector is synchronized.
Performance	Arraylist are faster as it is not synchronized.	Vector performance is slow as they are thread safe.
Resize	ArrayList grow half of its size when resized.	Vector grow double of its size when resized.
Iteration method	ArrayList does not uses enumerator for iteration.	Vector uses enumerator for  iteration.

Read carefully and understand the difference.
Enjoy Reading