Top 40+ Java Interview Questions And Answers In 2022
In this post, we see Core Java Interview Questions for Freshers and Experienced. This post covers Core Java Interview Questions for Selenium Automation Testers too. This post on Java Interview Questions is prepared with basic and important concepts of Java with examples for your easy understanding.
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Q12 What Are The Important Methods Of Java Exception Class
Exception and all of its subclasses doesnt provide any specific methods and all of the methods are defined in the base class Throwable.
How To Swap Two Numbers Without Using A Third Variable
Itâs a slightly tricky question. Itâs a three steps process. Itâs better visualized in code.
int a = 10 int b = 20 b = b + a // now b is sum of both the numbersa = b - a // b - a = - a = b b = b - a // - b = a
We canât return multiple variables in Java. Since Java is Pass-by-Value and these are primitive data types, their values wonât change. For example, below swap function will not change the input integer values.
public static void swapNumbers public static void main
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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.
What Is Selenium Ide
Selenium IDE is implemented as Firefox extension which provides record and playback functionality on test scripts. It allows testers to export recorded scripts in many languages like HTML, Java, Ruby, RSpec, Python, C#, JUnit and TestNG.
Selenium IDE has limited scope, and the generated test scripts are not very robust, and portable.
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How Can You Debug The Tests In The Selenium Ide
This is one of the most asked selenium interview questions
- We need to first insert the breakpoints where we need to debug and execute the test step by step.
- Later, Run the test case.
- After this, the execution stops at the point where the breakpoint is kept.
- You can click on the Run button to continue the execution of all the commands sequentially.
What Is Constructor In Java
Constructor in Java is used in the creation of an Object that is an instance of a Class. The constructor name should be the same as the class name. It looks like a method but its not a method. It wont return any value. We have seen that methods may return a value. If there is no constructor in a class, then the compiler automatically creates a default constructor.
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What Are The Testing Types That Are Supported By Selenium
Regression Testing and Functional Testing are majorly supported by Selenium.
All the Test cases are executed repeatedly either partially or as a full to ensure that the existing functionalities are working as designed. It includes the following steps,
- Re-testing: All the test cases in the Test Suite are executed which proves to be time-consuming and expensive.
- Regression Test case Selection: The test cases are classified or categorized as features tests, integration tests etc., and some test cases are selected.
- Prioritization of Test cases: The test cases that are selected are prioritized based on the critical functionalities and business impact.
In this, all the functions in the application are verified with a specific requirement. This is primarily the black-box testing as it is not concerned about the source code of the application. It includes the following steps,
- Test Input is identified.
- The test case is executed
- The actual outcome and the test outcome are compared accordingly.
How Is The Desired Capability Useful In Terms Of Selenium
A series of key-value pairs can be used to store information like the browser name, browser version, the path of the browser driver in the system, etc., to determine the behavior of the browser at the run-time. This feature or functionality is commonly referred to as desired capability.
For Selenium,
The driver instance can be configured using this.
It comes into practice when you want to run the test cases in different operating systems, browsers, and versions.
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What Are The Testing Types Supported By Selenium
Selenium supports Regression testing and Functional testing.
Regression testing – It is a full or partial selection of already executed test cases that are re-executed to ensure existing functionalities work fine.
The steps involved are –
Functional testing – Functional Testing involves the verification of every function of the application with the required specification.
The following are the steps involved:
What Is The Major Difference Between Driverclose And Driverquit
driver.close:
Its a command by which the current window can be closed. For example, if we have multiple browser windows open then, by using this command we can close the window with which the focus is.
driver.quit:
This command closes all the browser windows which are open. For example, if we have multiple browser windows open then, this command can close all the windows at once.
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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.
Explain Xpath Absolute And Xpath Attributes
XPath has two main types of expressions: absolute and relative. Absolute expressions always start with a forward slash , which indicates the root element of the document. Relative expressions do not start with a forward slash, and are relative to the current context.
Attributes are another important part of XPath. Attributes are added to elements and can contain valuable information about that element. In order to access an attribute, you must use the at sign followed by the attribute name.
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Java Interview Questions For Selenium Automation Testing
Java Interview Questions for Selenium Automation Testing | This tutorial has listed 100++ frequently asked interview questions based on important topics during Java technical interview round for Selenium automation testing.
During an interview, the same question can be asked in many different ways. So, be confident in an interview. Interviewers are interested in listening not just the correct answer, but also your knowledge about the topic.
Here, listed Java interview questions for Selenium automation testing with the best possible answers will be helpful to get complete knowledge and tackle the interview.
Your approach towards understanding the questions and sharing your answers plays an extremely important role in an interview success.
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What Is Selenese How Is It Classified
Selenese is the set of Selenium commands which are used to test your web application. The tester can test the broken links, the existence of some object on the UI, Ajax functionality, alerts, window, list options, and a lot more using Selenese.
Action: Commands which interact directly with the application
Accessors: Allow the user to store certain values to a user-defined variable
Assertions: Verifies the current state of the application with an expected state
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Can You Mention Why Do You Need The Session Handling In Selenium
Session handling is very important while working with Selenium. This is because while working with the test case scenarios we need to establish the communication between the browser and the application while executing the commands. There can be an issue where while running a particular test script, another test script can be triggered within the same host and same type of browser. This is the most important part and the reason why we need the session handling.
Explain The Difference Between Assert And Verify Commands
The assert command is used to check if the given condition is true or not. If the condition is true, then the execution of the program will continue. If the condition is false, then the execution of the program will stop.
The verify command is used to check if the given condition is true or not. If the condition is true, then the execution of the program will continue. If the condition is false, then the execution of the program will not stop, but an error message will be displayed.
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What Is The Difference Between Assert And Verify Statements In Selenium
Assert:
- We can check whether an element is on the page or not.
- The test fails and gets terminated whenever there is a fail in the check. That is the program control flow stops.
Verify:
- Its only to specify whether the given condition is true or false.
- The program control flow does not stop due to this.
Overall, the Verify statement does not halt the program execution whereas the Assert statement does halt the execution.
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How Will You Use Jsp El In Order To Get The Http Method Name
Using pageContext JSP EL implicit object you can get the request object reference and make use of the dot operator to retrieve the HTTP method name in the JSP page. The JSP EL code for this purpose will look like $.
In case you are facing any challenges with these java interview questions, please comment on your problems in the section below. Apart from this Java Interview Questions Blog, if you want to get trained from professionals on this technology, you can opt for structured training from edureka!
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Why Are Strings Immutable In Java
In Java, String is immutable to make sure that the string value doesnt change. String literals are usually shared between multiple clients. If the value of the string changes , it will affect all reference variables and cause severe discrepancies.Hence, strings are immutable in Java. Making string immutable enhances security, caching, synchronization, and performance of the application.
Why Do We Use Selenium Rc
- Selenium IDE has the limitations which Selenium RC can diminish in terms of browser support and language support.
- IDE does not support many functions like Logging, iterations, conditional statements, test case results reporting etc., as it supports only HTML Language.
- Thats why the Selenium RC is used to communicate with the other languages like Perl, Python etc.,
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What Makes Selenium Such A Widely Used Testing Tool Give Reasons
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How Many Parameters Do Selenium Commands Have At A Minimum
There are four parameters that you must pass in Selenium. They are as follows,
We can bind the Selenium to a specific IP address instead of a Local host in our local machine.
We can specify the port number too i.e., TCP/IP port to connect the Selenium tests to the Grid hub. We need to make sure that there is no other application with the same port number up in any other location within the same machine.
The browser in which the selenium scripts have to be executed.
The application URL triggers the test cases within that.
How To Use Foreach Method
The forEach method provides a shortcut to perform an action on all the elements of an iterable. Letâs say we have to iterate over the list elements and print it.
List< String> list = new ArrayList< > Iterator< String> it = list.iterator while )
We can use forEach method with lambda expression to reduce the code size.
List< String> list = new ArrayList< > list.forEach
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How To Login To Any Site If It Is Showing An Authentication Pop
To handle authentication pop-ups, verify its appearance and then handle them using an explicit wait command.
Use the explicit wait command
WebDriverWait wait = new WebDriverWait
Alert class is used to verify the alert
Alert alert = wait.until)
Once verified, provide the credentials
alert.authenticateUsing)
You Cannot Use Extra Space The First Index Of Occurrence And The Last Index Of Occurrence Will Be
We will keep three variables. The 2 variables firstIndex and lastIndex will be initialized to -1. The third will be a boolean type variable found which will be initially false. If the element is found, we will make it true, and store the current index in firstIndex and lastIndex variables. If the element is found further, only the lastIndex variable will change. The fact that the number has already been found in the array will be denoted by the found boolean variable.
Java Program to find the First and Last Occurrence of an element in the Array
import java.util.* classMainint target = scn.nextInt int fIndex = -1, lIndex = -1 boolean found = false for else } }if else }}
Sample Output
Input:5123252Output: First Index = 1 Last Index = 3
When the element does not exist
Input:5123252Output:The element does not exist in the array.
- Corner Cases, You might Miss: The corner case of elements not present in the array is something that should be taken care of separately. In our code, we use the boolean variable found to do so. Otherwise, we can directly see if the values of fIndex and lIndex variables are -1 or not.
- Time Complexity: O as we are traversing the array.
- Auxiliary Space: O as we have not used any extra space to solve the problem.
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Write A Program To Show A Single Thread In Java
Java Program to show Single Thread
publicclassMain}
Output
When the sentence is a palindrome
Input: 2 Race, e cAr 2Output: true
When the sentence is not a palindrome
Input: 2 Race, a cAr 2Output: false
- Corner cases, You Might Miss: It is very important to convert all the alphabets in the String to lowercase. If this is not done, our answer will not be correct. Also, the special case of the string being empty is not handled separately as the program automatically covers this test case by not including any character of the string. So, according to our program, an empty string will be a palindrome.
- If you want that the answer should be false in the case of an empty string, you can apply this condition in the isStrPalindrome function.
- Time Complexity: O where N is the length of the input string.Auxiliary Space: O as we have not used any extra space.
Top 20 Java Interview Programs For Programming And Coding Interview
In this tutorial, we have provided a big list of basic Java interview programs with actual logical code examples asked in Programming and Coding Interviews for freshers and experienced candidates.
Important and basic Java programs that are generally asked in the technical round of Java and Automation Interviews.
This has now become a general practice by the interviewers to ask basic Java Programs in interviews rather than just focusing on theoretical aspects.
For this, we have come up with an idea of listing down a few very important Java Programs along with the proper explanation of each program.
Moreover, we have also included the respective outputs which will give you a fair idea about how that program worked. The flow of the program and the concepts are properly explained wherever possible throughout this article.
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