Important Selenium Interview Questions And Answers

Posted on June 9, 2017 by Shakti Das

These are the major question asked in the interview Important Selenium Interview Questions And Answers

1) What is Selenium and what is Selenium composed of?

Selenium is a test suite of for automated web testing. It is composed of

Selenium IDE (Integrated Development Environment) : It is record and run tool for recording and playing back o execution. It is a firefox plugin.
WebDriver and RC: It provide the APIs for a variety of languages like Java, .NET, PHP, etc. With most of the browsers Webdriver and RC works.
Grid: With the help of Grid you can distribute tests on multiple machines so that test can be run parallel which helps in cutting down the time required for running in browser test suites

2) What is Selenium 2.0 ?

Web Testing tools Selenium RC and WebDriver are consolidated in single tool in Selenium 2.0

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3) Mention what is Selenium 3.0?

Selenium 3.0 is the latest version of Selenium. It has released 2 beta versions of selenium 3.0 with few of the below changes:

Here are few new features added to Selenium 3.0

Beta 1 updates	Beta 2 updates (Only for Java)
Minimum Java version is now 8+	System property webdriver.firefox.marionette now forces the server in marionette or legacy firefox driver mode, ignoring any related Desired Capability
It will support for Firefox Via Mozilla’s geckodriver	Grid fixes NPE’s on registration when -browser not specified
Support for Edge is provided by MS It now supports Safari on MacOS via Apple’s own Safari driver	Update GeckoDriver –port argument in all bindings

4) How will you find an element using Selenium?

In Selenium every object or control in a web page is referred as an elements, there are different ways to find an element in a web page they are

ID
Name
Tag
Attribute
CSS
Linktext
PartialLink Text
Xpath etc

5) List out the test types that are supported by Selenium?

For web based application testing selenium can be used

The test types can be supported are

a) Functional, Learn More about Functional Testing.

b) Regression

For post release validation with continuous integration automation tool could be used

a) Jenkins

b) Hudson

c) Quick Build

d) CruiseCont

6) Explain what is assertion in Selenium and what are the types of assertion?

Assertion is used as a verification point. It verifies that the state of the application conforms to what is expected. The types of assertion are “assert” , “verify” and “waifFor”.

7) Mention what is the use of X-path?

X-Path is used to find the WebElement in web pages. It is also useful in identifying the dynamic elements.

Refer Complete Guide on XPath

8) Explain the difference between single and double slash in X-path? Single slash ‘/ ’

Single slash ( / ) start selection from the document node
It allows you to create ‘absolute’ path expressions

Double Slash ‘// ’

Double slash ( // ) start selection matching anywhere in the document
It enables to create ‘relative’ path expressions

9) List out the technical challenges with Selenium? Technical challenges with Selenium are

Selenium supports only web based applications
It does not support the Bitmap comparison
For any reporting related capabilities have to depend on third party tools
No vendor support for tool compared to commercial tools like HP UFT
As there is no object repository concept in Selenium, maintainability of objects becomes difficult

10) What is the difference between type keys and type commands ?

TypeKeys() will trigger JavaScript event in most of the cases whereas .type() won’t. Type key populates the value attribute using JavaScript whereas .typekeys() emulates like actual user typing

11) What is the difference between verify and assert commands?

Assert: Assert allows to check whether an element is on the page or not. The test will stop on the step failed, if the asserted element is not available. In other words, the test will terminated at the point where check fails.

Verify: Verify command will check whether the element is on the page, if it is not then the test will carry on executing. In verification, all the commands are going to run guaranteed even if any of test fails.

12) What is JUnit Annotations and what are different types of annotations which are useful ?

In JAVA a special form of syntactic meta-data can be added to Java source code, this is know as Annotations. Variables, parameters, packages, methods and classes are annotated some of the Junit annotations which can be useful are

Test
Before
After
Ignore
BeforeClass
AfterClass
RunWith

13) While using click command can you use screen coordinate?

To click on specific part of element, you would need to use clickAT command. ClickAt command accepts element locator and x, y co-ordinates as arguments- clickAt (locator, cordString)

14) What are the advantages of Selenium?

It supports C#, PHP, Java, Perl, Phython
It supports different OS like Windows, Linux and Mac OS
It has got powerful methods to locate elements (Xpath, DOM , CSS)
It has highly developer community supported by Google

15) Why testers should opt for Selenium and not QTP?

Selenium is more popular than QTP as

Selenium is an open source whereas QTP is a commercial tool.
Selenium is used specially for testing web based applications while QTP can be used for testing client server application also.
Selenium supports Firefox, IE, Opera, Safari on operating systems like Windows, Mac, Linux etc. however QTP is limited to Internet Explorer on Windows.
Selenium supports many programming languages like Ruby, Perl, Python whereas QTP supports only VB script

16) What are the four parameter you have to pass in Selenium? Four parameters that you have to pass in Selenium are

Host
Port Number
Browser
URL

17) What is the difference between setSpeed() and sleep() methods?

Both will delay the speed of execution.

Thread.sleep () : It will stop the current (java) thread for the specified period of time. Its done only once

It takes a single argument in integer format

Ex: thread.sleep(2000)- It will wait for 2 seconds

It waits only once at the command given at sleep

SetSpeed () : For specific amount of time it will stop the execution for every selenium command.

It takes a single argument in integer format

Ex: selenium.setSpeed(“2000”)- It will wait for 2 seconds

Runs each command after setSpeed delay by the number of milliseconds mentioned in set Speed

This command is useful for demonstration purpose or if you are using a slow web application

18) What is same origin policy? How you can avoid same origin policy?

The “Same Origin Policy” is introduced for security reason, and it ensures that content of your site will never be accessible by a script from another site. As per the policy, any code loaded within the browser can only operate within that website’s domain.

To avoid “Same Origin Policy” proxy injection method is used, in proxy injection mode the Selenium Server acts as a client configured HTTP proxy , which sits between the browser and application under test and then masks the AUT under a fictional URL

19) What is heightened privileges browsers?

The purpose of heightened privileges is similar to Proxy Injection, allows websites to do something that are not commonly permitted. The key difference is that the browsers are launced in a special mode called heightened privileges. By using these browser mode, Selenium core can open the AUT directly and also read/write its content without passing the whole AUT through the Selenium RC server.

20) How you can use “submit” a form using Selenium ?

You can use “submit” method on element to submit form-

element.submit () ;

Alternatively you can use click method on the element which does form submission

21) What are the features of TestNG and list some of the functionality in TestNG which makes it more effective?

TestNG is a testing framework based on JUnit and NUnit to simplify a broad range of testing needs, from unit testing to integration testing. And the functionality which makes it efficient testing framework are

Support for annotations
Support for data-driven testing
Flexible test configuration
Ability to re-execute failed test cases

22) Mention what is the difference between Implicit wait and Explicit wait?

Implicit Wait: Sets a timeout for all successive Web Element searches. For the specified amount of time it will try looking for element again and again before throwing a NoSuchElementException. It waits for elements to show up.

Explicit Wait : It is a one-timer, used for a particular search.

23) Which attribute you should consider throughout the script in frame for “if no frame Id as well as no frame name”?

You can use…..driver.findElements(By.xpath(“//iframe”))….

This will return list of frames.

You will ned to switch to each and every frame and search for locator which we want.

Then break the loop

24) Explain what is the difference between find elements () and find element () ?

find element ():

It finds the first element within the current page using the given “locating mechanism”. It returns a single WebElement

findElements () : Using the given “locating mechanism” find all the elements within the current page. It returns a list of web elements.

25) Explain what are the JUnits annotation linked with Selenium?

The JUnits annotation linked with Selenium are

@Before public void method() – It will perform the method () before each test, this method can prepare the test
@Test public void method() – Annotations @Test identifies that this method is a test method environment
@After public void method()- To execute a method before this annotation is used, test method must start with test@Before

26) Explain what is Datadriven framework and Keyword driven?

Datadriven framework: In this framework, the test data is separated and kept outside the Test Scripts, while test case logic resides in Test Scripts. Test data is read from the external files ( Excel Files) and are loaded into the variables inside the Test Script. Variables are used for both for input values and for verification values.

Keyworddriven framework: The keyword driven frameworks requires the development of data tables and keywords, independent of the test automation. In a keyword driven test, the functionality of the application under test is documented in a table as well as step by step instructions for each test.

27) Explain how you can login into any site if it’s showing any authentication popup for password and username?

Pass the username and password with url

Syntax-http://username:password@url
ex- http://creyate:[email protected]

28) Explain how to assert text of webpage using selenium 2.0 ?

WebElement el = driver.findElement(By.id(“ElementID”))

//get test from element and stored in text variable

String text = el.getText();

//assert text from expected

Assert.assertEquals(“Element Text”, text);

29) Explain what is the difference between Borland Silk and Selenium?

Silk Test Tool	Selenium Test Tool
Borland Silk test is not a free testing tool	Selenium is completely free test automation tool
Silk test supports only Internet Explorer and Firefox	Selenium supports many browsers like Internet Explorer, Firefox, Safari, Opera and so on
Silk test uses test scripting language	Selenium suite has the flexibility to use many languages like Java, Ruby,Perl and so on
Silk test can be used for client server applications	Selenium can be used for only web application

30) What is Object Repository ?

An object repository is an essential entity in any UI automations which allows a tester to store all object that will be used in the scripts in one or more centralized locations rather than scattered all over the test scripts.

31) Explain how Selenium Grid works?

Selenium Grid sent the tests to the hub. These tests are redirected to Selenium Webdriver, which launch the browser and run the test. With entire test suite, it allows for running tests in parallel.

32) Can we use Selenium grid for performance testing?

Yes. But not as effectively as a dedicated performance testing tool like Loadrunner.

33) List the advantages of Webdriver over Selenium Server?

If you are using Selenium-WebDriver, you don’t need the Selenium Server as it is using totally different technology
Selenium Server provides Selenium RC functionality which is used for Selenium 1.0 backwards compatibility
Selenium Web driver makes direct calls to browser using each browsers native support for automation, while Selenium RC requires selenium server to inject Javascript into the browser

34) Mention what are the capabilities of Selenium WebDriver or Selenium 2.0 ?

WebDriver should be used when requiring improvement support for

Handling multiple frames, pop ups , multiple browser windows and alerts
Page navigation and drag & drop
Ajax based UI elements
Multi browser testing including improved functionality for browser not well supported by Selenium 1.0

35) While injecting capabilities in webdriver to perform tests on a browser which is not supported by a webdriver what is the limitation that one can come across?

Major limitation of injecting capabilities is that “findElement” command may not work as expected.

36) Explain how you can find broken images in a page using Selenium Web driver ?

To find the broken images in a page using Selenium web driver is

Get Xpath and get all the links in the page using tag name
In the page click on each and every link
Look for 404/500 in the target page title

37) Explain how you can handle colors in web driver?

To handle colors in web driver you can use

Use getCssValue(arg0) function to get the colors by sending ‘color’ string as an argument

38) Using web driver how you can store a value which is text box?

You can use following command to store a value which is text box using web driver

driver.findElement(By.id(“your Textbox”)).sendKeys(“your keyword”);

39) Explain how you can switch between frames?

To switch between frames webdrivers [ driver.switchTo().frame() ] method takes one of the three possible arguments

A number: It selects the number by its (zero-based) index
A number or ID: Select a frame by its name or ID
Previously found WebElement: Using its previously located WebElement select a frame

40) Mention 5 different exceptions you had in Selenium web driver?

The 5 different exceptions you had in Selenium web drivers are

WebDriverException
NoAlertPresentException
NoSuchWindowException
NoSuchElementException
TimeoutException

41) Explain using Webdriver how you can perform double click ?

You can perform double click by using

Syntax- Actions act = new Actions (driver);
act.doubleClick(webelement);

42) How will you use Selenium to upload a file ?

You can use “type”command to type in a file input box of upload file. Then, you have to use “Robot” class in JAVA to make file upload work.

43) Which web driver implementation is fastest?

HTMLUnit Driver implementation is fastest, HTMLUnitDriver does not execute tests on browser but plain http request, which is far quick than launching a browser and executing tests

44) Explain how you can handle frames using Selenium 2.0 ?

To bring control on HTML frame you can use “SwitchTo” frame method-

driver.switchTo().frame(“frameName”);

To specify a frame you can use index number

driver.switchTo().frame(“parentFrame.4.frameName”);

This would bring control on frame named- “frameName” of the 4^th sub frame names “parentFrame”

45) What is the difference between getWindowhandles() and getwindowhandle() ?

getwindowhandles(): It is used to get the address of all the open browser and its return type is iterator<String>

getwindowhandle(): It is used to get the address of the current browser where the control is and return type is string

46) Explain how you can switch back from a frame?

To switch back from a frame use method defaultContent()

Syntax-driver.switchTo().defaultContent();

47) List out different types of locators?

Different types of locators are

By.id()
By.name()
By.tagName()
By.className()
By.linkText()
By.partialLinkText()
By.xpath
By.cssSelector()

48) What is the command that is used in order to display the values of a variable into the output console or log?

In order to display a constant string, command can be used is echo <constant string>
If order to display the value of a variable you can use command like echo ${variable name>>

Above is using PHP. If you are using Java, replace echo with System.out.println

49) Explain how you can use recovery scenario with Selenium?

Recovery scenarios depends upon the programming language you use. If you are using Java then you can use exception handling to overcome same. By using “Try Catch Block” within your Selenium WebDriver Java tests

50) Explain how to iterate through options in test script?

To iterate through options in test script you can loop features of the programming language, for example to type different test data in a text box you can use “for” loop in Java

// test data collection in an array

String[ ] testData = { “test1” , “test2” , “test3” } ;

// iterate through each test data

For (string s: test data) { selenium.type ( “elementLocator”, testData) ; }

51) How can you prepare customized html report using TestNG in hybrid framework ?

There are three ways

Junit: With the help of ANT
TestNG: Using inbuilt default.html to get the HTML report. Also XST reports from ANT, Selenium, TestNG combinations
Using our own customized reports using XSL jar for converting XML content to HTML

52) From your test script how you can create html test report?

To create html test report there are three ways

TestNG: Using inbuilt default.html to get the HTML report. Also XLST reports from ANT, Selenium, TestNG combination
JUnit: With the help of ANT
Using our own customized reports using XSL jar for converting XML content to HTML

53) Explain how you can insert a break point in Selenium IDE ?

In Selenium IDE to insert a break point

Select “Toggle break point” by right click on the command in Selenium IDE
Press “B” on the keyboard and select the command in Selenium IDE
Multiple break points can be set in Selenium IDE

54) Explain in Selenium IDE how can you debug the tests?

Insert a break point from the location from where you want to execute test step by step
Run the test case
At the given break point execution will be paused
To continue with the next statement click on the blue button
Click on the “Run” button to continue executing all the commands at a time

55) What is Selenese and what are the types of Selenese ?

Selenese is a selenium set of command which are used for running the test

There are three types of Selenese

Actions: It is used for performing the operations and interactions with the target elements
Assertions: It is used as a check points
Accessors: It is used for storing the values in a variable

56) Explain what are the limitations of Selenium IDE?

The limitations of Selenium IDE

Exceptional handling is not present
Selenium IDE uses only HTML languages
External databases reading is not possible with IDE
Reading from the external files like .txt, .xls is not possible
Conditional or branching statements execution like if,else, select statements is not possible

57) What are the two modes of views in Selenium IDE ?

Either Selenium IDE can be opened as a pop up window or in side bar

58) In selenium IDE what are the element locators that can be used to locate elements on web page?

In selenium there are mainly 4 locators that are used

X-path locators
Css locators
Html id
Html name

59) In Selenium IDE how you can generate random numbers and dates for test data ?

In Selenium IDE you can generate random numbers by using Java Script

type

css=input#s

javascript{Math.random()}

And for

type

css=input#s

javascript{new Date()}

60) How you can convert any Selenium IDE tests from Selenese to another language?

You can use the format option of Selenium IDE to convert tests into another programming language

61) Using Selenium IDE is it possible to get data from a particular html table cell ?

You can use the “storeTable” command

Example store text from cell 0,2 from an html table

storeTable

Css=#table 0.2

textFromCell

62) Explain what can cause a Selenium IDE test to fail?

When a locator has changed and Selenium IDE cannot locate the element
When element Selenium IDE waiting to access did not appear on the web page and the operation timed out
When element Selenium IDE was trying to access was not created

63) Explain how you can debug the tests in Selenium IDE ?

Insert a break point from the location where you want to execute step by step
Run the test case
At the given break point execution will be paused
To continues with the next step click on the Blue button
To run commands at a time click on run button

64) From Selenium IDE how you can execute a single line?

From Selenium IDE single line command can be executed in two ways

Select “Execute this command” by right clicking on the command in Selenium IDE
Press “X” key on the keyboard after selecting the command in Selenium IDE

65) In which format does source view shows your script in Selenium IDE ?

In Selenium IDE source view shows your script in XML format

66) Explain how you can insert a start point in Selenium IDE?

In two ways selenium IDE can be set

Press “S” key on the keyboard and select the command in Selenium IDE

In Seleniun IDE right click on the command and the select “Set / Clear Start Point”

67) What if you have written your own element locator and how would you test it?

To test the locator one can use “Find Button” of Selenium IDE, as you click on it, you would see on screen an element being highlighted provided your element locator is right or or else an error message will be displayed

68) What is regular expressions? How you can use regular expressions in Selenium ?

A regular expression is a special text string used for describing a search pattern. In Selenium IDE regular expression can be used with the keyword- regexp: as a prefix to the value and patterns needs to be included for the expected values.

69) What are core extension ?

If you want to “extend” the defualt functionality provided by Selenium Function Library , you can create a Core Extension. They are also called “User Extension”. You can even download ready-made Core Extension created by other Selenium enthusiats.

70) How will you handle working with multiple windows in Selenium ?

We can use the command selectWindow to switch between windows. This command uses the title of Windows to identify which window to switch to.

71) How will you verify the specific position of an web element

You can use verifyElementPositionLeft & verifyElementPositionTop. It does a pixel comparison of the position of the element from the Left and Top of page respectively

72) How can you retrive the message in an alert box ?

You can use the storeAlert command which will fetch the message of the alert pop up and store it in a variable.

73) What is selenium RC (Remote Control)?

Selenium IDE have limitations in terms of browser support and language support. By using Selenium RC limitation can be diminished.

On different platforms and different web browser for automating web application selenium RC is used with languages like Java, C#, Perl, Python
Selenium RC is a java based and using any language it can interact with the web application
Using server you can bypass the restriction and run your automation script running against any web application

74) Why Selenium RC is used?

Selenium IDE does not directly support many functions like condition statements, Iteration, logging and reporting of test results, unexpected error handling and so on as IDE supports only HTML language. To handle such issues Selenium RC is used it supports the language like Perl, Ruby, Python, PHP using these languages we can write the program to achieve the IDE issues.

75) Explain what is the main difference between web-driver and RC ?

The main difference between Selenium RC and Webdriver is that, selenium RC injects javascript function into browsers when the page is loaded. On the other hand, Selenium Webdriver drives the browser using browsers built in support

76) What are the advantages of RC?

Advantages of RC are

Can read or write data from/ to .xls, .txt, etc
It can handle dynamic objects and Ajax based UI elements
Loops and conditions can be used for better performance and flexibility
Support many Programming languages and Operating Systems
For any JAVA script enabled browser Selenium RC can be used

77) Explain what is framework and what are the frameworks available in RC?

A collection of libraries and classes is known as Framework and they are helpful when testers has to automate test cases. NUnit, JUnit, TestNG, Bromine, RSpec, unittest are some of the frameworks available in RC .

78) How can we handle pop-ups in RC ?

To handle pop-ups in RC , using selectWindow method, pop-up window will be selected and windowFocus method will let the control from current window to pop-up windows and perform actions according to script

79) What are the technical limitations while using Selenium RC?

Apart from “same origin policy” restriction from js, Selenium is also restricted from exercising anything that is outside browser.

80) Can we use Selenium RC to drive tests on two different browsers on one operating system without Selenium Grid?

Yes, it is possible when you are not using JAVA testing framework. Instead of using Java testing framework if you are using java client driver of selenium then TestNG allows you to do this. By using “parallel=test” attribute you can set tests to be executed in parallel and can define two different tests, each using different browser.

81) Why to use TestNG with Selenium RC ?

If you want full automation against different server and client platforms, You need a way to invoke the tests from a command line process, reports that tells you what happened and flexibility in how you create your test suites. TestNG gives that flexibility.

82) Explain how you can capture server side log Selenium Server?

To capture server side log in Selenium Server, you can use command

java –jar .jar –log selenium.log

83) Other than the default port 4444 how you can run Selenium Server?

You can run Selenium server on java-jar selenium-server.jar-port other than its default port

84) How Selenium grid hub keeps in touch with RC slave machine?

At predefined time selenium grid hub keeps polling all RC slaves to make sure it is available for testing. The deciding parameter is called “remoteControlPollingIntervalSeconds” and is defined in “grid_configuration.yml”file

85) Using Selenium how can you handle network latency ?

To handle network latency you can use driver.manage.pageloadingtime for network latency

86) To enter values onto text boxes what is the command that can be used?

To enter values onto text boxes we can use command sendkeys()

87) How do you identify an object using selenium?

To identify an object using Selenium you can use

isElementPresent(String locator)

isElementPresent takes a locator as the argument and if found returns a Boolean

88) In Selenium what are Breakpoints and Startpoints?

Breakpoints: When you implement a breakpoint in your code, the execution will stop right there. This helps you to verify that your code is working as expected.
StartpointsStartpoint indicates the point from where the execution should begin. Startpoint can be used when you want to run the testscript from the middle of the code or a breakpoint.

89) Mention why to choose Python over Java in Selenium?

Few points that favor Python over Java to use with Selenium is,

Java programs tend to run slower compared to Python programs.
Java uses traditional braces to start and ends blocks, while Python uses indentation.
Java employs static typing, while Python is dynamically typed.
Python is simpler and more compact compared to Java.

90) Mention what are the challenges in Handling Ajax Call in Selenium Webdriver?

The challenges faced in Handling Ajax Call in Selenium Webdriver are

Using "pause" command for handling Ajax call is not completely reliable. Long pause time makes the test unacceptably slow and increases the testing time. Instead, "waitforcondition" will be more helpful in testing Ajax applications.
It is difficult to assess the risk associated with particular Ajax applications
Given full freedom to developers to modify Ajax application makes the testing process challenging
Creating automated test request may be difficult for testing tools as such AJAX application often use different encoding or serialization technique to submit POST data.

91) Mention what is IntelliJ?

Intellij is an IDE that helps you to write better and faster code for Selenium. Intellij can be used in the option to Java bean and Eclipse.

92) Mention in what ways you can customize TestNG report?

You can customize TestNG report in two ways,

Using ITestListener Interface
Using IReporter Interface

93) To generate pdf reports mention what Java API is required?

To generate pdf reports, you need Java API IText.

94) Mention what is Listeners in Selenium WebDriver?

In Selenium WebDriver, Listeners "listen" to the event defined in the selenium script and behave accordingly. It allows customizing TestNG reports or logs. There are two main listeners i.e. WebDriver Listeners and TestNG Listeners.

95) Mention what are the types of Listeners in TestNG?

The types of Listeners in TestNG are,

IAnnotationTransformer
IAnnotationTransformer2
IConfigurable
IConfigurationListener
IExecutionListener
IHookable
IInvokedMethodListener
IInvokedMethodListener2
IMethodInterceptor
IReporter
ISuiteListener
ITestListener

96) Mention what is desired capability? How is it useful in terms of Selenium?

The desired capability is a series of key/value pairs that stores the browser properties like browser name, browser version, the path of the browser driver in the system, etc. to determine the behavior of the browser at run time.

For Selenium,

It can be used to configure the driver instance of Selenium WebDriver.
When you want to run the test cases on a different browser with different operating systems and versions.

97) For Database Testing in Selenium Webdriver what API is required?

For Database Testing in Selenium Webdriver, you need JDBC (Java Database Connectivity) API. It allows you to execute SQL statements.

98) Mention when to use AutoIT?

Selenium is designed to automate web-based applications on different browsers. But to handle window GUI and non-HTML popups in the application you need AutoIT. know more about How to use AutoIT with Selenium

99) Mention why do you need Session Handling while working with Selenium?

While working with Selenium, you need Session Handling. This is because, during test execution, the Selenium WebDriver has to interact with the browser all the time to execute given commands. At the time of execution, it is also possible that, before current execution completes, someone else starts execution of another script, in the same machine and in the same type of browser. So to avoid such situation you need Session Handling.

100) Mention what are the advantages of Using Git Hub For Selenium?

The advantages of Using Git Hub for Selenium are

Multiple people when they work on the same project they can update project details and inform other team members simultaneously.
Jenkins can help you to build the project from the remote repository regularly. This helps you to keep track of failed builds.

Different types of Command used in Structural Query Language(SQL)

Posted on March 26, 2017 by Shakti Das

Different type of Command used in SQL basically categories by their functionality. These functions include building database objects, manipulating objects, populating database tables with data, updating existing

data in tables, deleting data, performing database queries, controlling database access, and overall database administration.The following are the different types of command.

The main categories are

DDL (Data Definition Language)
DML (Data Manipulation Language)
DQL (Data Query Language)
DCL (Data Control Language)
Data administration commands
Transactional control commands

These SQL commands are mainly categorized into four categories as discussed below:

DDL(Data Definition Language) : DDL or Data Definition Language actually consists of the SQL commands that can be used to define the database schema. It simply deals with descriptions of the database schema and is used to create and modify the structure of database objects in database.Examples of DDL commands:
- CREATE – is used to create the database or its objects (like table, index, function, views, store procedure and triggers).
- DROP – is used to delete objects from the database.
- ALTER-is used to alter the structure of the database.
- TRUNCATE–is used to remove all records from a table, including all spaces allocated for the records are removed.
- COMMENT –is used to add comments to the data dictionary.
- RENAME –is used to rename an object existing in the database.
DML(Data Manipulation Language) : The SQL commands that deals with the manipulation of data present in database belong to DML or Data Manipulation Language and this includes most of the SQL statements.Examples of DML:
- SELECT – is used to retrieve data from the a database.
- INSERT – is used to insert data into a table.
- UPDATE – is used to update existing data within a table.
- DELETE – is used to delete records from a database table.
DCL(Data Control Language) : DCL includes commands such as GRANT and REVOKE which mainly deals with the rights, permissions and other controls of the database system.Examples of DCL commands:
- GRANT-gives user’s access privileges to database.
- REVOKE-withdraw user’s access privileges given by using the GRANT command.
TCL(transaction Control Language) : TCL commands deals with the transaction within the database.Examples of TCL commands:
- COMMIT– commits a Transaction.
- ROLLBACK– rollbacks a transaction in case of any error occurs.
- SAVEPOINT–sets a save point within a transaction.
- SET TRANSACTION–specify characteristics for the transaction.

If you have any further clarification on this topic please give comment below in Different types of Command used in Structural Query Language(SQL)

Selenium Wait Implicit Wait Explicit Wait Fluent Wait

Posted on March 11, 2017 by Shakti Das

Selenium Wait Command is used in Selenium WebDriver to wait a particular amount of time defined by user.Selenium Wait can be divided into two categories Implicit wait and Explicit wait and another type of hybrid wait is Fluent Wait.In the implicit wait selenium WebDriver wait for a fixed amount of time before executing next command or throwing an exception . Where in all other Selenium Wait type of WebDriver will execute the next line of command if it found that element.

Implicit wait

This is the Selenium Wait statement gives command to the browser to wait for an certain period of time in that time if the element is located in the page the execution will take place or else the “WebDriver wait” for a specific amount of time to check whether the element is located on that page or not.

driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

[codesyntax lang=”java”]

package tesng;
public class robot { protected WebDriver driver;
 @Test public void tutorials() throws InterruptedException { 
System.setProperty("webdriver.gecko.driver", "D:\\geckodriver.exe");
 driver = new FirefoxDriver(); driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS); 
driver.get("http://www.marketwatch.com/"); System.out.println(driver.findElement(By.linkText("The Moneyologist")).getTagName()); } }

[/codesyntax]

In above example the WebDriver wait for 10 Second to find the link text is present or not.

Note for implicit-From Selenium 3.0.1 release the WebDriver is not throwing the exception “Element not Found Exception” instead of it is waiting for element to be present.

Explicit wait

An explicit wait is a wait statement let the user to define for a certain condition and predefined time to wait for proceeding further in the code. The Explicit wait wait for an particular event to occur in that period of time to perform any operation on that web element.

   WebElement DynamicElement = (new WebDriverWait(driver, 10))
                .until(ExpectedConditions.presenceOfElementLocated(By.xpath(".//input[@type='text']")));

[codesyntax lang=”java”]

package tesng;

public class explicit_wait {    
 protected WebDriver driver;    
 @Test     public void guru99tutorials() throws InterruptedException {   
      System.setProperty("webdriver.gecko.driver", "D:\\geckodriver.exe");    
     driver = new FirefoxDriver();        driver.get("http://www.google.co.in");   
      WebElement DynamicElement = (new WebDriverWait(driver, 10)).until(ExpectedConditions.presenceOfElementLocated(By.xpath(".//input[@type='text']")));     } }

[/codesyntax]

The WebDriver will for a maximum 10 second to check the presence of the element located by xpath if in between 10 seconds the driver is finding that element it will execute the next step.

Selenium Fluent Wait

Fluent Wait is an special type of Selenium Wait used to find the object when the object is dynamic in nature. It will check the presence of element in particular interval time and will handle exception by its own if the element is not currently visible.

We can use this Selenium Fluent Wait in the scenarios where we do not sure whether the element is visible or not. If the element is visible we will perform operation in it if not visible the fluent wait will handle the error by its own.

In this bellow example i have taken 2 second for the presence of element and in each 250 millisecond it will check whether the element is visible or not till end of 2 second by Selenium Fluent Wait.

Syntax-
Driver declaration
Waiting Time setting in driver
Function declaration and function definition(With driver and web element as parameter )
Function call

Example-

[codesyntax lang=”java”]

FluentWait wait=new FluentWait(driver);
wait.poolingEvery(250,TimeUnit.MILISECONDS);
wait.withTimeout(2, TimeUnit.SECONDS);
wait.ignoring(TimeoutException.class);
Function<WebDriver, Boolean> function = new Function<WebDriver, Boolean>() {
public Boolean apply(WebDriver arg) {
WebElement element = arg
.findElement(By.xpath("//div[contains(text(),'You already have a Mailbox named')]"));
if (element.isDisplayed()) {
System.out.println("Found");
arg.findElement(By.xpath("//button[@class='btn pull-right create-toggle']")).click();
return true;
} else {
System.out.println("Not Found");
return false;
}
}
};
wait.until(function);

[/codesyntax]

Thread.Sleep(Time)

Thread.Sleep is the worst method for “Selenium Wait” so we do not advise to use this type of wait in the program unless until u need this. This Thread.Sleep() will pause your java program for an specific duration.

Code

Thread.Sleep(1000);

All the Selenium Wait methods we are discuses above are need for different time in Selenium WebDriver So please use the require Selenium Wait for your definite purpose.

Eclipse Shortcuts Windows, Mac, and Linux

Posted on January 22, 2017 by Shakti Das

1. Shortcuts

1.1. Using shortcuts in Eclipse

Using shortcuts make a developer more productive. Eclipse provides keyboard shortcuts for the most common actions. Using shortcuts is usually preferable as you can perform actions much faster.

Eclipse supports of course the typical shortcuts, e.g. Ctrl+S for saving, Ctrl+C for copying the selected text or file and Ctrl+V for pasting the element currently in the clipboard.

1.2. Shortcuts on Mac OS

This description uses the shortcuts based on Windows and Linux. Mac OS uses the Cmd key frequently instead of the Ctrl key.

2. Quick Access

The Ctrl+3 shortcut allows you to perform all available actions in Eclipse. This shortcut puts the focus into the Quick Access (quick access) search box which allows you to execute any Eclipse command. For example you can open a Preference, a Wizard, a view and a Preference page.

You can also use QuickAccess to search for an opened editor by typing in the name of the resource which the editor shows.

The following screenshot shows how you the available commands in quick access for the “New Java” search term.

Table 1. Navigation
Shortcut	Description
`Ctrl`+`Shift`+`R`	Search dialog for resources, e.g., text files
`Ctrl`+`Shift`+`T`	Search dialog for Java Types
`Ctrl`+`F8`	Shortcut for switching perspectives

Table 2. Navigation between editors
Shortcut	Description
`Ctrl`+`E`	Search dialog to select an editor from the currently open editors
`Alt`+`←`	Go to previous opened editor. Cursor is placed where it was before you opened the next editor
`Alt`+`→`	Similar Alt + ← but opens the next editor
`Ctrl`+`Q`	Go to editor and the position in this editor where the last edit was done
`Ctrl`+`PageUp`	Switch to previous opened editor
`Ctrl`+`PageDown`	Switch to next opened editor

Table 3. Navigation between views
Shortcut	Description
`Ctrl`+`F7`	Shortcut for switching views. Choose the view to switch to with your mouse or cycle through the entries with repeating the keystroke
`Shift`+`Alt`+`Q`	Open menu for switch view keybindings
`Shift`+`Alt`+`Q`+`P`	Show package explorer
`Shift`+`Alt`+`Q`+`C`	Show console

4. Start Java programs

Table 4. Running programs
Shortcut	Description
`Ctrl`+`F11`	Run last launched
`F11`	Run last launched in debug mode
`Ctrl`+`Alt`+`B`	Skip all breakpoints. Let’s you use debug mode for code reloading
`Alt`+`Shift`+`X`+`J`	Run current selected class as Java application
`Alt`+`Shift`+`X`+`T`	Run JUnit test
`Alt`+`Shift`+`X`+`P`	Run JUnit Plug-in test

5. Editing in the Java editor

Table 5. Handling the editor
Shortcut	Description
`Shift`+`Alt`+`↑`	Selects enclosing elements.,result depending on cursor position

Table 6. Handling the editor
Shortcut	Description
`Ctrl`+`1`	Quickfix; result depending on cursor position
`Ctrl`+`Space`	Content assist/ code completion
`Ctrl`+`T`	Show the inheritance tree of the current Java class or method.
`Ctrl`+`O`	Show all methods of the current class, press Ctrl + O again to show the inherited methods.
`Ctrl`+`M`	Maximize active editor or view
`Ctrl`+`Shift`+`F`	Format source code
`Ctrl`+`I`	Correct indentation, e.g., format tabs/whitespaces in code
`Ctrl`+`F`	Opens the find dialog
`Shift`+`Enter`	Adds a link break at the end of the line
`Ctrl`+`Shift`+`O`	Organize the imports; adds missing import statements and removes unused ones
`Alt`+`Shift`+`Z`	Wrap the select block of code into a block, e.g. try/catch.

Table 7. Cursor navigation and text selection
Shortcut	Description
`Ctrl`+`←` or `Ctrl`+`→`	Move one text element in the editor to the left or right
`Ctrl`+`↑` or `Ctrl`+`↓`	Scroll up / down a line in the editor
`Ctrl`+`Shift`+`P`	Go to the matching bracket
`Shift`+`Cursor movement`	Select text from the starting position of the cursor
`Alt`+`Shift ↑ / ↓`	Select the previous / next syntactical element
`Alt`+`Shift ↑ / ↓ / ← / →`	Extending / reducing the selection of the previous / next syntactical element

Table 8. Copy and move lines
Shortcut	Description
`Ctrl`+`Alt`+`↓`	Copy current line below the line in which the cursor is placed
`Ctrl`+`Alt`+`↑`	Copy current line above the line in which the cursor is placed
`Alt`+`Up`	Move line one line up
`Alt`+`Down`	Move line one line down

Table 9. Delete
Shortcut	Description
`Ctrl`+`D`	Deletes line
`Ctrl`+`Shift`+`DEL`	Delete until end of line
`Ctrl`+`DEL`	Delete next element
`Ctrl`+`BACKSPACE`	Delete previous element

Table 10. Create new lines
Shortcut	Description
`Shift`+`Enter`	Adds a blank line below the current line and moves the cursor to the new line. The difference between a regular enter is that the currently line is unchanged, independently of the position of the cursor.
`Ctrl`+`Shift`+`Enter`	Same as Shift + Enter but above

Table 11. Variable assignment
Shortcut	Description
`Ctrl`+`2`+`L`	Assign statement to new local variable
`Ctrl`+`2`+`F`	Assign statement to new field

6. Coding

Table 12. Coding
Shortcut	Description
`Shift`+`F2`	Show the Javadoc for the selected type / class / method
`Alt`+`Shift`+`N`	Shortcut for the menu to create new objects
`Alt`+`Shift`+`Z`	Surround block with try and catch

7. Refactoring

Table 13. Refactoring
Shortcut	Description
`Alt`+`Shift`+`R`	Rename
`Ctrl`+`2`+`R`	Rename locally (in file), faster than Alt + Shift + R
`Alt`+`Shift`+`T`	Opens the context-sensitive refactoring menu, e.g., displays

8. Minimum

The following shortcuts are the absolute minimum a developer should be familiar with to work efficient in Eclipse.

Table 14. Must known shortcuts
Shortcut	Description
`Ctrl`+`S`	Saves current editor
`Ctrl`+`1`	Quickfix; shows potential fixes for warnings, errors or shows possible actions
`Ctrl`+`Space`	Content assist/ code completion
`Ctrl`+`Q`	Goes to the last edited position
`Ctrl`+`D`	Deletes current line in the editor
`Ctrl`+`Shift`+`O`	Adjusts the imports statements in the current Java source file
`Ctrl`+`2`+`L or F`	Assign statement to new local variable or field
`Ctrl`+`Shift`+`T`	Open Type Dialog
`Ctrl`+`O`	Shows quick outline of a class
`Ctrl`+`F11`	Run last launched application
`Shift`+`F10`	Opens context menu. Keyboard equivalent to Mouse2
`Ctrl`+`F10`	Opens view menu for current view.

Polymorphism in Java Static Polymorphism/Compile time polymorphism vs Dynamic Polymorphism/Run time Ploymorphism

Posted on January 22, 2017 by Shakti Das

Polymorphism in the java as the word poly means “More than one” and morph ism means “Functionality” is also applicable in java,where the function behave the more than one way, With same function name and different parameter.

For instance, let’s consider a class Animal and let Cat be a subclass of Animal. So, any cat IS animal. Here, Cat satisfies the IS-A relationship for its own type as well as its super class Animal.

Note: It’s also legal to say every object in Java is polymorphic in nature, as each one passes an IS-A test for itself and also for Object class.

Static Polymorphism/Compile time polymorphism:

In Java, static polymorphism is achieved through method overloading. Method overloading means there are several methods present in a class having the same name but different types/order/number of parameters.

At compile time, Java knows which method to invoke by checking the method signatures. So, this is called compile time polymorphism or static binding. The concept will be clear from the following example:

class DemoOverload{

    public int add(int x, int y){  //method 1

    return x+y;

    }

    public int add(int x, int y, int z){ //method 2

    return x+y+z;

    }

    public int add(double x, int y){ //method 3

    return (int)x+y;

    }

    public int add(int x, double y){ //method 4

    return x+(int)y;

    }

}

class Test{

    public static void main(String[] args){

    DemoOverload demo=new DemoOverload();

    System.out.println(demo.add(2,3));      //method 1 called

    System.out.println(demo.add(2,3,4));    //method 2 called

    System.out.println(demo.add(2,3.4));    //method 4 called

    System.out.println(demo.add(2.5,3));    //method 3 called

    }

}

In the above example, there are four versions of add methods. The first method takes two parameters while the second one takes three. For the third and fourth methods there is a change of order of parameters. The compiler looks at the method signature and decides which method to invoke for a particular method call at compile time.

Dynamic Polymorphism/Run time Ploymorphism:

Suppose a sub class overrides a particular method of the super class. Let’s say, in the program we create an object of the subclass and assign it to the super class reference. Now, if we call the overridden method on the super class reference then the sub class version of the method will be called.

Have a look at the following example.

class Vehicle{

    public void move(){

    System.out.println(“Vehicles can move!!”);

    }

}

class MotorBike extends Vehicle{

    public void move(){

    System.out.println(“MotorBike can move and accelerate too!!”);

    }

}

class Test{

    public static void main(String[] args){

    Vehicle vh=new MotorBike();

    vh.move();    // prints MotorBike can move and accelerate too!!

    vh=new Vehicle();

    vh.move();    // prints Vehicles can move!!

    }

}

It should be noted that in the first call to move(), the reference type is Vehicle and the object being referenced is MotorBike. So, when a call to move() is made, Java waits until runtime to determine which object is actually being pointed to by the reference. In this case, the object is of the class MotorBike. So, the move() method of MotorBike class will be called. In the second call to move(), the object is of the class Vehicle. So, the move() method of Vehicle will be called.

As the method to call is determined at runtime, this is called dynamic binding or late binding.

If you have any further clarification on this topic please give comment below post Polymorphism in Java Static Polymorphism/Compile time polymorphism vs Dynamic Polymorphism/Run time Ploymorphism

Access Modifiers in Java ,How Access Level Helps in Inheritance and Polymorphism

Posted on January 22, 2017 by Shakti Das

In java their are 4 access modifiers public,protected,<default>,<package>,private

Public-Public is the access modifiers which shows the highest visibility any class member declare as public can be visible
1.Within the class.
2.Within the package.
3.Outside the package.
Protected-Any class member declare as protected are visible
1.Within the class.
2.Within the package.
3.Out side the package but only in the case of is-a relationship.
Default-
If we do not any access modifier to declare then the class member is consider as default member.
1.Default member are visible within the class
2.Within the package.
Private-
Private is the access modifier which shows the least visibility if we declare any member as private then it is visible
1.Only within that classes.

Understanding all java access modifiers

Let’s understand the access modifiers by a simple table.

Access Modifier	within class	within package	outside package by subclass only	outside package
Private	Y	N	N	N
Default	Y	Y	N	N
Protected	Y	Y	Y	N
Public	Y	Y	Y	Y

If you have any further clarification on Access Modifiers in Java ,How Access Level Helps in Inheritance and Polymorphism please give comment bellow

Java Autoboxing and Unboxing with examples

Posted on January 22, 2017 by Shakti Das

Java 1.5 introduced a special feature of auto conversion of primitive types to the corresponding Wrapper class and vice versa.

Autoboxing: Automatic conversion of primitive types to the object of their corresponding wrapper classes is known as autoboxing. For example – conversion of int to Integer, long to Long, double to Double etc.

Unboxing: It is just the reverse process of autoboxing. Automatically converting an object of a wrapper class to its corresponding primitive type is known as unboxing. For example – conversion of Integer to int, Long to long, Double to double etc.

Primitive type Wrapper classboolean Booleanbyte Bytechar Characterfloat Floatint Integerlong Longshort Shortdouble Double

When does the autoboxing and unboxing happens in Java

Autoboxing

: Lets see few cases with examples, where autoboxing happens.
Case 1: When a method is expecting a wrapper class object but the value that is passed as parameter is a primitive type. For example in the below code, the method myMethod() is expecting an object of Integer wrapper class, however we passed a primitive int type. The program ran fine as compiler does the autoboxing (conversion of int to Integer)

class AutoboxingExample1{ public static void myMethod(Integer num){ System.out.println(num); } public static void main(String[] args) { /* passed int (primitive type), it would be * converted to Integer object at Runtime */ myMethod(2); }}

Output:

Case 2: When at some point of time, you are assigning a primitive type value to an object of its wrapper class. For example: The below statements are valid because compiler does the autoboxing at runtime.

Integer inum = 3; //Assigning int to Integer: AutoboxingLong lnum = 32L; //Assigning long to Long: Autoboxing

Case 3: When dealing with collection framework classes:

ArrayList<Integer> arrayList = new ArrayList<Integer>();arrayList.add(11); //Autoboxing – int primitive to IntegerarrayList.add(22); //Autoboxing

Here ArrayList class is expecting an Integer wrapper class object but we are providing int primitive.

Unboxing

Case 1: Method is expecting Integer object (parameter) but we have supplied int. Auotmatic conversion(unboxing) happened that converted Integer to int.

class UnboxingExample1{ public static void myMethod(int num){ System.out.println(num); } public static void main(String[] args) { Integer inum = new Integer(100); /* passed Integer wrapper class object, it * would be converted to int primitive type * at Runtime */ myMethod(inum); }}

Output:

100

Case 2: Assignments

Integer inum = new Integer(5);int num = inum; //unboxing object to primitive conversion

Case 3: While dealing with collection classes:

ArrayList arrayList = new ArrayList()int num = arrayList.get(0); // unboxing because get method returns an Integer object

What happens behind the scenes?

In the above section we learnt how java compiler performs automatic conversion between primitive type and corresponding Wrapper objects. Lets discuss what compiler actually does during autoboxing and unboxing. The best way to understand this is to compare things before java 1.5 and after java 1.5 (boxing and unboxing introduced in java 1.5).

Autoboxing:
What we see:

Integer number = 100;

What compiler does (or what we used to do before java 1.5):

Integer number = Integer.valueOf(100);

Unboxing:
What we see:

Integer num2 = new Integer(50);int inum = num2;

What compiler does:

Integer num2 = new Integer(50);int inum = num2.intValue();

Similar things happen with the other wrapper classes and primitive types such as long, double, short etc.

Few things you should take care:

Do not mix primitives and objects while doing comparisons. You might get unpredictable results for such comparisons. Better thing to do is: compare object with objects (using equals() method) and compare primitive with primitives(using logical operators such as “==”, “<” etc).

SQL Insert Command Different Types

Posted on January 22, 2017 by Shakti Das

SQL Insert Command Different Types
Different type of SQL command are used to perform same operation need to use at different time as per our requirement.We can use them in the next example we are going to create a table name as TEST and heaving the following command.

Create Table command

CREATE TABLE TEST(ID NUMBER(10),NAME VARCHAR2(30));

Type-1

INSERT INTO TABLENAME(COLUMN1,COLUMN2) VALUES (VALUES1,VALUES2);

eg-insert into test(id,name) values(1,’shak’);

Type-2

eg-insert into test values(2,’data1′);

Type-3

eg-insert into test(‘&id’,’&name’);

Alter Command For Add Renaming Column

Posted on January 22, 2017 by Shakti Das

Alter table command is used to modify the table structure we can add a column or modify column.

Syntax
ALTER TABLE table_name
ADD column_name datatype

eg-alter table test add mobile number(10);

Modifying a column

Syntax

ALTER TABLE “table_name”
RENAME COLUMN “column 1” TO “column 2”;

Alter table Modify

Posted on January 22, 2017 by Shakti Das

This command is used to alter table existing data type.By giving this command we can change the parameter of an table.

ALTER TABLE table_name MODIFY column_name column_type;

alter table emp modify id number(20);

Learn Scripting

Author: Shakti Das

Important Selenium Interview Questions And Answers

Different types of Command used in Structural Query Language(SQL)

If you have any further clarification on this topic please give comment below in Different types of Command used in Structural Query Language(SQL)

Selenium Wait Implicit Wait Explicit Wait Fluent Wait

Implicit wait

Explicit wait

Selenium Fluent Wait

Eclipse Shortcuts Windows, Mac, and Linux

1. Shortcuts

1.1. Using shortcuts in Eclipse

1.2. Shortcuts on Mac OS

2. Quick Access

3. Navigation and text selection

4. Start Java programs

5. Editing in the Java editor

6. Coding

7. Refactoring

8. Minimum

Polymorphism in Java Static Polymorphism/Compile time polymorphism vs Dynamic Polymorphism/Run time Ploymorphism

Static Polymorphism/Compile time polymorphism:

Dynamic Polymorphism/Run time Ploymorphism:

If you have any further clarification on this topic please give comment below post Polymorphism in Java Static Polymorphism/Compile time polymorphism vs Dynamic Polymorphism/Run time Ploymorphism

Access Modifiers in Java ,How Access Level Helps in Inheritance and Polymorphism

Understanding all java access modifiers

If you have any further clarification on Access Modifiers in Java ,How Access Level Helps in Inheritance and Polymorphism please give comment bellow

Java Autoboxing and Unboxing with examples

When does the autoboxing and unboxing happens in Java

Autoboxing

Unboxing

What happens behind the scenes?

Few things you should take care:

SQL Insert Command Different Types

Alter Command For Add Renaming Column

Alter table Modify