Java/Selenium

How do you run code from command prompt?

• open command prompt and change directory to the file_path using cd file_path

• compile the file using javac file_name

• run the file using java file_name

What are the foundations of OOPS?

• abstraction - abstract classes and interfaces

  • abstract methods CANNOT be static and do not contain a body

  • when an abstract class is called by a non-abstract class, the methods have to be overriden in the non-abstract class even if not used.

  • abstract classes CANNOT be instantiated (have an object created of them)

    • uses keyword extends

  • abstract classes are used as a blueprint of a class to reduce code redundancy

  • interface uses keyword implements

• polymorphism - method and object overloading

  • method overloading - multiple methods with same names as long as they have different parameters

  • object overloading - className objectName = new constructorName();

    • if constructorName is different from className then the constructorName is the subclass of the superClass className

    • objects can be created from the same class but with different constructors

• inheritance - overriding

  • uses keyword extends

  • methods and variables from superClass can be used in subClass now

  • can only extends one class at a time but can be chained —> C extends B, B extends A, C will have all of B and A

  • keyword final:

    • variable = cannot be changed

    • class = cannot be inherited

• encapsulation - getters and setters

  • sometimes variables are set as private in order to limit access

  • in order to access these private variables then public methods from the same class that manipulate them can be called

    • getters - getter method is used to fetch the variable

    • setters - setter method is used to change the variable

what is a constructor?

A constructor is a special method that has no return type, non-static, can have access modifiers, and must be the same name as the class.

• when you create an object of a constructor (instantiate), the constructor is invoked so the constructor can be used to initialize properties.

• can have multiple constructors as long as they have different parameters

what is the this keyword?

this is used to refer to the current instance (object) in a method/constructor

• used mostly when variables have the same name to give clarity

• only used with non-static methods/constructors

Explain non-static vs static

• non-static - when you create an object of a class an instance of that class is created. So changes to that instance of the class are not reflected on the original or other instances of the same class

• static - there is no separation. any changes done to the original will be reflected on anything that calls it

what is break vs continue?

• continue - will stop the code for that iteration of the loop but continue on with the rest of the loop until it’s finished

• break - will stop the execution of the rest of the code for that iteration and the rest of the loop

what is while loop vs do-while loop

• while loop will condition before running the loop

• do-while loop will always run the code in the body once before checking the condition to loop

how to tell if a number is even?

use the MOD operator %

• if n%2 == 0 then the number is even

how to tell if a word is a palindrome?

• set the string to a char array using .toCharArray()

• create a new empty String variable to save the reversedWord

• use a for loop to concatenate the chars into the reversedWord String variable starting with the last letter decrementing

• set each to lower case using .toLowerCase() to make it not case sensitive

• then compare the original String and reversedWord String using an if condition to see if they match

what does keyword final mean in terms of variables, methods, and classes?

• variables - means it cannot be changed

• methods - it cannot be overridden but can be inherited

  • classes - cannot be inherited

what is overloading vs overriding?

• overloading is having multiple methods with the same name but with different parameters

  • comes from polymorphism

• overriding is when a subClass has the same method name and arguments as a superClass, calling the method will call the local method and override the superClass

  • can be worked around by using the super keyword

  • comes from inheritance

  • keyword final can be used to stop overriding

what is ArrayList vs LinkedList? which one do you use more often?

• ArrayList - the items are added in as a queue. so if any items in the middle or beginning are removed then all items are shuffled back to fill that space. so it is a little slower when dealing with large amounts of data.

• LinkedList - the items are added in a linked chain. so if any items in the middle or beginning are removed then only the connection to the link is move. so it is faster when dealing with large amounts of data cuz there isn’t much data moving around

• ArrayList is used more often in my work activities because i don’t deal with enough data to warrant using LinkedLists

how do you connect to a database using java?

• setup properties for the JDBC driver using Class.forName(JDBC driver)

• create a connection to the DB using DriverManager.getConnection(url, username, password)

• empower the connection reference variable to give it the power to execute queries by creating a statement object using statement = .createStatement() method

• execute the queries using the .executeQuery() method to return a ResultSet object

• loop thru the ResultSet using a while loop with conditions while( resultSet.next()) to extract the data from the columns based on columnName and save that to a columnValue variable

• close the connection with a finally block using if connection and resultset != null .close() method respectively

how would you remove duplicate letters in a String?

• use a LinkedHashMap to keep letters in order as theyve been added

• Set an empty String variable for the new String

• set the original String to an array using .toCharArray()

• iterate thru the new Array using a for loop where it will set each char as the key and 1 as the value

• with an if condition that if the char does not already have value 1 in the map then it will be added to the map with that value and then concat into the new String variable

name some data collections

• list

  • ArrayList, LinkedList

• set

  • HashSet, LinkedHashSet, TreeSet

• map

  • HashMap, LinkedHashMap, TreeMap

ArrayList vs Array

• array - fixed size

• ArrayList - dynamic size

runtime vs compile time

• compile time - shows an error while compiling before running. shows which method will be run during compile time

  • example is method overloading. method that will be run is determined by parameters

• run time - shows an error after executing. determines which method will be run when you execute

  • overriding

how do you get text from an element? get page title?

.getText() method

.getTitle() method

how do you deal with dynamic elements?

• use relative xpath

• find a stable element and make a relative xpath of it

• then use xpath axes to get to the desired element

what are the different types of xpaths?

• absolute - start at the root node and then go all the way to the desired element

• relative - find the element in relation to a node

what are the testNG annotations?

• @BeforeSuite

• @BeforeTest

• @BeforeClass

• @BeforeMethod

• @Test

• @AfterMethod

• @AfterClass

• @AfterTest

• @AfterSuite

what is @DataProvider?

used to connect to the datasheet to run the same test but with multiple sets of data

project object model vs page object model

• project object model - an .xml file that contains dependencies that configure the project once built

• page object model - a design pattern used to test web applications where each individual page of an application will have its own class. the class will contain WebElements found on that page and methods that utilize the elements

what are the different waits in selenium?

• explicit - waits for a condition with a specific amount of time

• implicit - waits a specific amount of time to look for WebElements

• fluent - waits for a condition with a specific amount of time with polling intervals where it checks if the condition is met

what are some common exceptions you’ve encountered in selenium?

• NullPointerException - object reference being used isn’t initialized so it’s null

• NoSuchElementException - element cannot be found

• AssertionError - expected condition is not met

• FileNotFoundException - file not found at given path

• TimeoutException - excepted condition is not met with a WebDriverWait

• IOException

how do you handle drop down elements?

Use the Select class to select/deselect options in a dropdown

• use method .selectByVisibleText(), .selectByIndex(), .selectByValue(),

how to handle alerts/popups?

use the .switchTo().alert() method with either

• .dismiss()

• .accept()

• .getText()

• .sendKeys()

how to handle iFrames?

• use .switchTo().frame(“frameName”)

• have to return to default frame in between switching frames with .switchTo().parentFrame() OR .switchTo().defaultContent()

how to send keyboard events

• use Actions class

• with .sendKeys(keyName.ENTER).build().perform()

how to mouse hover

• use Actions class

• with .moveToElement(WebElement).build().perform()

how to deal with multiple tabs?

• use .switchTo().window(windowHandle)

• find window handle with .getWindowHandle()

how to read config files?

• use either:

  • FileReader

  • BufferedReader

  • InputStream

  • Scanner

• InputStream example:

  • Create InputStream object with FilePath

    • InputStream input = new FileInputStream(“filePath”)

  • create properties object as prop

  • use prop.load(input)

  • use prop.getProperty(“keyName”) to get the value

what is GitHub

• git = repository to store codes

• GitHub = open source web based software that hosts git services

what is a test suite? test case? test step?

• test suite = test class

• test case = method annotated by @Test

• test step = statements ending with semicolon

what is cucumber?

cucumber is an automation testing tool used as a bridge between a feature file written in gherkin to step definitions written in java. runs the test cases with a runner class

• Given - pre-condition

• When - action taken

• Then - validation