Difference between Collections and Collection in java with example program

Difference between Collections and Collection in java with example program

Famous java interview question: difference between collections and collection in java
Major difference between Collection and Collections is Collection is an interface and Collections is a class.
Both are belongs to java.util package
Collection is base interface for list set and queue.
Collections is a class and it is called utility class.
Collections utility class contains some predefined methods so that we can use while working with
Collection type of classes(treeset, arraylist, linkedlist etc.)
Collection is base interface for List , Set and Queue.


Collection vs Collections

public interface Collection<E>
extends Iterable<E>


public class Collections
extends Object

Collections utility class contains static utility methods so that we can use those methods by using
class name without creating object of Collections class object
Lest see some methods of Collections class.


addAll: public static <T> boolean addAll(Collection<? super T> c,T... elements)
reverseOrder: public static <T> Comparator<T> reverseOrder()
shuffle: public static void shuffle(List<?> list)
sort:public static <T extends Comparable<? super T>> void sort(List<T> list)
How to Relate Collection and Collections
ArrayList is a Collection type of class means it is implementing Collection interface internally
Now lets see a java example program to sort ArrayList of elements using Collections.sort() method.

public class ArrayList<E>
extends AbstractList<E>
implements List<E>, RandomAccess, Cloneable, Serializable


1.Basic Java example program to sort arraylist of integers using Collections.sort() method

package com.javasortarraylistofobjects;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;

public class SortArrayListExample{

public static void main(String[] args) {

//create an ArrayList object
 ArrayList<Integer> arrayList = new ArrayList<Integer>();
     
 //Add elements to Arraylist
arrayList.add(10);
arrayList.add(7);
arrayList.add(11);
arrayList.add(4);
arrayList.add(9);
arrayList.add(6);
arrayList.add(2);
arrayList.add(8);
arrayList.add(5);
arrayList.add(1);
     
     
 System.out.println("Before sorting ArrayList ...");
 Iterator itr=arrayList.iterator();
     
while (itr.hasNext()) {

System.out.println(itr.next());
   
}

     
 /*
 To sort an ArrayList object, use Collection.sort method. This is a
  static method. It sorts an ArrayList object's elements into ascending order.
*/
  Collections.sort(arrayList);
   
  System.out.println("After sorting ArrayList ...");
     
 
     
Iterator itr1=arrayList.iterator();
     
while (itr1.hasNext()) {

System.out.println(itr1.next());
         
}
 

}
}



Output:

Before sorting ArrayList ...
10
7
11
4
9
6
2
8
5
1
After sorting ArrayList ...
1
2
4
5
6
7
8
9
10
11

How to Automate Radio button and Checkbox in Selenium webdriver

How to Automate Radio button and Checkbox in Selenium webdriver

                      HTML For Checkbox

                   <input type=”checkbox”>

                     For Radio Button

                    <input type=”radio”>

Automate radio button and checkbox in selenium

When you inspect these elements via firebug and firepath you will get above html type.

The main difference between radio button and checkbox is checkbox you can select multiple but for radio button, only one selection is possible.

In Selenium we have 1 method called click() to perform click events.

This click() method you can apply with radio button, checkbox, links and sometime with dropdown as well.

Let us get started

Demo Code

WebElement ele=driver.findElement(By.id());

ele.click();

WebElement ele=driver.findElement(By.id());

ele.click();

In this example I have used id only but if you want to make you script stable then you should use Xpath and CSS in your script.

Before performing click action, sometimes we need to verify some activity as well, take some example

You need to verify whether radio button or checkbox is enabled.

You need to verify whether radio button or checkbox is Displayed on UI or not.

You need to verify whether checkbox and radio button is default selected or not.

Above validations are must used in script because automation is all about validation only. You will get these type of questions in interviews also.

These words looks quite big while listening but we can easily verify this using some predefined method in Selenium.

These methods are

isDisplayed();

isEnabled();

isSelected();

isSelected();

Therefore, you must be eager now how to use these methods in script so let us see these methods using a single program.

Program to Automate radio button and checkbox in selenium

 import org.openqa.selenium.By;

import org.openqa.selenium.WebDriver;

import org.openqa.selenium.WebElement;

import org.openqa.selenium.firefox.FirefoxDriver;

public class FacebookDropdown {

     public static void main(String[] args) throws Exception {

          WebDriver driver=new FirefoxDriver();

          driver.manage().window().maximize();

          driver.get("http://www.facebook.com");

         WebElement male_radio_button=driver.findElement(By.id("u_0_e"));

         boolean status=male_radio_button.isDisplayed();

         System.out.println("Male radio button is Displayed >>"+status);

          boolean enabled_status=male_radio_button.isEnabled();

          System.out.println("Male radio button is Enabled >>"+enabled_status);

        boolean selected_status=male_radio_button.isSelected();

          System.out.println("Male radio button is Selected >>"+selected_status);

          male_radio_button.click();

        boolean selected_status_new=male_radio_button.isSelected();

          System.out.println("Male radio button is Selected >>"+selected_status_new);

     }

}

 import org.openqa.selenium.By;

import org.openqa.selenium.WebDriver;

import org.openqa.selenium.WebElement;

import org.openqa.selenium.firefox.FirefoxDriver;

public class FacebookDropdown {

     public static void main(String[] args) throws Exception {

          WebDriver driver=new FirefoxDriver();

          driver.manage().window().maximize();

          driver.get("http://www.facebook.com");

         WebElement male_radio_button=driver.findElement(By.id("u_0_e"));

         boolean status=male_radio_button.isDisplayed();

         System.out.println("Male radio button is Displayed >>"+status);

          boolean enabled_status=male_radio_button.isEnabled();

          System.out.println("Male radio button is Enabled >>"+enabled_status);

        boolean selected_status=male_radio_button.isSelected();

          System.out.println("Male radio button is Selected >>"+selected_status);

          male_radio_button.click();

        boolean selected_status_new=male_radio_button.isSelected();

          System.out.println("Male radio button is Selected >>"+selected_status_new);

     }

}

 Explanation- If you notice above scenario before click Selected status was false but after click status changed to TRUE.

Output:

Male radio button is display>>>true

Male radio button is Enable>>true

Male radio button is selected>>false

Click on radio button

Male radio button is selected>>True

     

Java Program to Sort elements of Java ArrayList Example

1.Basic Java example program to sort arraylist of integers

1. package com.javasortarraylistofobjects;
2.  
3. import java.util.ArrayList;
4. import java.util.Collections;
5. import java.util.Iterator;
6.  
7. public class SortArrayList{
8.  
9. public static void main(String[] args) {
10.   
11. //create an ArrayList object
12.  ArrayList<Integer> arrayList = new ArrayList<Integer>();
13.        
14.  //Add elements to Arraylist
15. arrayList.add(10);
16. arrayList.add(7);
17. arrayList.add(11);
18. arrayList.add(4);
19. arrayList.add(9);
20. arrayList.add(6);
21. arrayList.add(2);
22. arrayList.add(8);
23. arrayList.add(5);
24. arrayList.add(1);
25.         
26.         
27.  System.out.println("Before sorting ArrayList ...");
28.  Iterator itr=arrayList.iterator();
29.         
30. while (itr.hasNext()) {
31.  
32. System.out.println(itr.next());
33.      
34. }
35.  
36.        
37.  /*
38.  To sort an ArrayList object, use Collection.sort method. This is a
39.   static method. It sorts an ArrayList object's elements into ascending order.
40. */
41.   Collections.sort(arrayList);
42.      
43.   System.out.println("After sorting ArrayList ...");
44.        
45.     
46.         
47. Iterator itr1=arrayList.iterator();
48.         
49. while (itr1.hasNext()) {
50. 
    
51. System.out.println(itr1.next());
52.             
53. }
54.     
55.   
56. }
57. }

OUTPUT::

1. Before sorting ArrayList ...
2. 10
3. 7
4. 11
5. 4
6. 9
7. 6
8. 2
9. 8
10. 5
11. 1
12. After sorting ArrayList ...
13. 1
14. 2
15. 4
16. 5
17. 6
18. 7
19. 8
20. 9
21. 10
22. 11