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ReactJS Interview Questions and AnswersReactJS is a JavaScript library that is used for building user interfaces. Facebook and an individual group of developers maintain it.
ReactJS is one of the top in-demand skills for web developers, primarily front-end and full-stack developers. As such, a front-end developer earns an average base salary of $129,145 per year. Hence, preparing well for ReactJS interviews can open various job prospects for candidates.
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Key Highlights
ReactJS interview questions involve core concepts such as JSX, state, props, and component lifecycle.
Experience building real-world applications using ReactJS can help demonstrate practical knowledge and problem-solving skills to the interviewer.
Good knowledge of JavaScript and ES6 features is essential to write clean and efficient code while working with ReactJS.
Excellent communication and collaboration skills and a willingness to learn and adapt to new technologies can help make a good impression on the interviewer.
Part 1 –ReactJS Interview Questions (Basic)This first part covers basic ReactJS Interview Questions and Answers:
Q1. What is React?Answer: React is a JavaScript library used for building user interfaces. ReactJS is used as a base of a single webpage or mobile application. It deals with the view layer of an application.
Q2. What is JSX?Answer: JSX is simple JavaScript that allows HTML syntax and other HTML tags in the code. HTML syntax is processed into JavaScript calls of React framework.
Q3. What is FLUX in ReactJS?Answer: Flux is an application architecture in React View Library that Facebook designed for creating data layers in an application based on JavaScript.
Q4. What are Props and States in React?Answer: Props mean the arguments’ properties passed in the JavaScript function. A state is used for creating a dynamic and interactive component.
Q5. What are refs in React?Answer: For focus management and trigger animation, one uses refs in React. It also contains third-party libraries.
Q6. What is the difference between ReactJS and AngularJS?Answer:
ReactJS AngularJS
A JavaScript library for building user interfaces. A full-featured JavaScript framework for building large-scale, complex web applications.
It uses a virtual DOM to update the actual DOM efficiently. It uses a two-way data binding approach, where any changes to the model automatically update the view and vice versa.
Follows a unidirectional data flow, where data flows only in one direction, from parent to child components. Follows a bidirectional data flow, where changes in the view automatically update the model, and changes in the model automatically update the view.
It provides more flexibility and control, allowing developers to use any other library or framework alongside it. It provides a complete solution for building web applications, including many built-in features like routing, forms, and animations.
A good understanding of JavaScript is required as it relies heavily on it. It relies more on declarative templates and requires less JavaScript knowledge.
Q7. How is flux different from Redux?Answer:
Flux Redux
Flux is an architectural pattern that Facebook introduced. Redux is a predictable state container that is based on Flux architecture.
Flux’s single dispatcher receives actions and dispatches them to the stores. The store receives dispatched actions directly, as Redux has no dispatcher.
Flux has multiple stores that contain the application state. Redux has a single store that contains the entire application state.
Flux stores can have mutable states and be changed anywhere in the application. Redux stores have an immutable state; the only way to change the state is by dispatching an action.
Flux has more boilerplate code and requires more setup. Redux has less boilerplate code and is easier to set up.
Q8. What do you mean by a functional component in React?Answer: A functional component is a component that returns React elements as an element.
Q9. What is routing?Answer:
The ability to switch between various pages or views of an application is called routing in React.
The React Router library implements routing in React applications.
Developers can design routes using essential components and properties because it supports declarative routing.
Routing is integral to building complex React applications, as it allows for better organization and separation of concerns between different parts of an application.
Q10. What are the components of Redux?Answer: Action, Reducer, Store, and View are the components of Redux.
Action: Describes a user’s intent in the form of an object.
Reducer: A pure function that receives the current state and an action and returns a new state.
Store: A centralized place to store the state of an application.
View: The user interface of an application.
Part 2 –ReactJS Interview Questions (Advanced) Q11. List the characteristics of ReactJS.Answer:
JSX: ReactJS has JSX. JSX is simple JavaScript that allows HTML syntax and other HTML tags in the code. The React framework processes HTML syntax into JavaScript calls.
React Native: It contains a native library that supports Native iOS and Android applications.
Simplicity: It is straightforward to grab. Its component-based approach and well-defined lifecycle are direct to use.
Easy to Learn: Anyone with basic programming knowledge can quickly learn ReactJS, for Learning ReactJS, one needs to know the basics of HTML and CSS.
Data-Binding: ReactJS uses one-way data binding and application architecture controls data flow via a dispatcher.
Testability: ReactJS application is straightforward to test. Its views are easy to configure and can be treated as an application.
Q12. What are the lifecycle methods of React Components in detail?Answer: Some of the most important lifecycles methods are given below:
componentWillMount()
componentDidMount()
componentWillRecieveProps()
shouldComponentUpdate()
componentWillUpdate()
Q13. What is the lifecycle of ReactJS?Answer:
Increased application performance.
Client and Server side building.
Reliable due to JSX code.
Easy testing.
Q15. Which company developed React? When was it released?Answer: Facebook developed ReactJS and developed it in March 2013.
Q16. What is the significance of the virtual DOM in ReactJS?Answer: In ReactJS, the virtual DOM is a lightweight copy of the actual DOM, which helps to enhance the application’s performance. Whenever there is a change in the state of a React component, the virtual DOM compares the new and previous states and creates a list of minimum necessary changes. It then updates the actual DOM with these changes, resulting in faster rendering and improved user experience.
Q17. What is the basic difference between pros and state?Answer:
Props
State
Definition Short for “properties,” passed from parent component to child component. User interactions or other events can change a component’s internal state over time.
Immutable Immutable (cannot be modified by the component receiving them) Mutable (can be adjusted using setState())
Update Trigger It can only be updated by the parent component passing in new props. You can update it by calling setState() or forceUpdate() within the component.
Usage Used to pass data from parent to child components. They manage components’ internal state and re-render based on state changes.
Scope It can be accessed throughout the component tree. It can only be accessed within the component where it is defined.
Q18. When to use a class component over a functional component?Answer:
Q19. How does one share the data between components in React?Answer:
Props: Using props is one method of transferring data from a parent component to a child component. Props are read-only, so the child component cannot alter the data passed through them.
Context: React context offers a mechanism to share data that any component within a specific context can access. It is most beneficial to share data necessary for multiple components, such as user authentication data.
Redux: Redux is a library for state management that offers a universal state store that any component can access. It enables components to dispatch actions to update the shop and subscribe to changes in the shop.
React Query: By caching and controlling the state of asynchronous data, React Query is a data fetching module that offers a mechanism to transfer data between components. Additionally, you can use React to manage the global state.
Local Storage: The ability to store data locally in the browser that may be accessed and shared by components is provided by local storage. We should only use local storage for modest amounts of data, not for confidential or sensitive data.
Q20. What are React hooks? Final ThoughtsMany businesses seek developers with experience in ReactJS, as it has become one of the most widely used JavaScript libraries for creating complex user interfaces. If one is preparing for the ReactJS interview, one should also prepare for JavaScript and must have practical hands-on. Preparing important concepts using interview questions can help one ace their interview.
Frequently Asked Questions (FAQs)Q1. How do I prepare for a React interview?
Answer: To prepare for a React interview, it’s essential to review the fundamentals of React, including its core concepts, lifecycle methods, and popular tools and libraries. You should also practice building small React applications and be able to explain your approach and decision-making process. Finally, be sure to research the company you’re interviewing with and familiarize yourself with their React-related projects or initiatives.
2. What is ReactJS used for?
Answer: ReactJS is a JavaScript library used for building user interfaces. It allows developers to create reusable UI components and manage the state of an application in a way that is efficient and easy to understand.
3. What questions are asked in interviews on ReactJS?
What is ReactJS?
What is Flux?
How do you define JSX?
What are Props and State?
What are refs?
4. How do you pass React interview questions?
Answer: To pass React interview questions, it’s essential to have a solid understanding of ReactJS’s core concepts and be able to apply them in practical scenarios. It’s also helpful to be familiar with popular React libraries and tools, such as Redux, React Router, and Jest. Practice building small React applications and be prepared to explain your thought process and decision-making. Finally, be confident, communicate clearly, and demonstrate a willingness to learn and adapt.
Recommended ArticlesWe hope that this EDUCBA information on “ReactJs Interview Questions” was beneficial to you. You can view EDUCBA’s recommended articles for more information.
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Top 10 Soa Interview Questions And Answers {Updated For 2023}
Introduction to SOA Interview Questions and Answers
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If you are looking for a job related to SOA, you need to prepare for the 2023 SOA Interview Questions. Every interview is indeed different as per the different job profiles. Here, we have prepared the important SOA Interview Questions and Answers, which will help you succeed in your interview.
In this 2023 SOA Interview Questions article, we shall present the 10 most essential and frequently used SOA interview questions. These questions will help students build their concepts around SOA and help them to crack the interview.
Part 1 – SOA Interview Questions (Basic)This first part covers basic Interview Questions and Answers.
Q1. Explain what SOA governance is and what are its functions.Service-Oriented Architecture governance is used to control services in any SOA. Some activities are defined as a part of SOA governance. This includes managing a portfolio of services that help plan and develop new services and update the already existing ones. It also includes managing the service lifecycle. This means that all updates of services should not interrupt the current customers and their services. Also, SOA provides consistency of all services by applying rules to all created services. It also offers monitoring services that help the customer know about the downtimes or underperformance of any system, which can be severe for a particular service. As a result, necessary actions can be taken whenever required, and all problems occurring can be instantly resolved by checking performance and availability.
Q2. What are the ends, contract, address, and bindings?The service can be made available to clients from different ends. All these services must be exposed through one of these ends.
Contract: It is an agreement that is agreed upon between two parties. It defines how clients are expected to communicate. It specifies the different parameters and returns values that are to be used.
Address: This specifies where a user can find a service. There is an address URL that points to the location of services.
Binding: This determines how to access the end. It specifies the process for communication and how it is to be done.
Q3. How can you achieve loose coupling in SOA?To achieve loose coupling, you can use a service interface like WSDL for a SOAP web service. To limit the dependency, you can hide the service implementation from the consumer. Loose coupling can be handled by encapsulating different functionalities in a way in which it will limit the impact of changes to the implementation of different service interfaces. Also, sometime you may have to change the interface and manage versioning without impacting the customers. Also, one can manage multiple security constraints, multiple transports, and other specifications.
Q4. Are web services and SOA the same?SOA is an architectural concept, while web services are used to complete them. Web services are the preferred standards that are satisfied to achieve the architectural specifications of SOA. When one uses SOA, all services need to be loosely coupled. Also, SOA services should be able to describe themselves, and WSDL services will be describing how we can access the services. Also, these services can be accessed through WSDL. SOA services are located in a directory, and here UDDI describes where these web services can be found.
Q5. What is a reusable service?Reusable service is a stateless functionality that has the required granularity. It can be a part of a composite application or composite server. A reusable service should be identified with any activity prescribed by the business and which has its specifications. A service constraint may be security, QoS, SLA or any usage policies. It may be defined by different runtime contracts, multiple interfaces, and different implementations. A reusable service is looked over at the enterprise-level throughout its lifecycle, starting from design time through its runtime. Its reuse should also be promoted through a pre-defined process, and its reuse can be measured.
Part 2 – SOA Interview Questions (Advanced) Q6. Explain Business Layers and Plumbing Layers in SOA. Q8. Explain what the composition of the service is.By using composition, services are combined to produce composite applications. This application consists of an aggregation of services where an enterprise portal or process is created. A composite service consists of an aggregation of different services which will provide reusable services. It acts like combining electronics components and create reusable composite services.
Q9. What is ESB, and where does it fit in?ESB stands for Enterprise Service Bus. Unlike other relationships, it provided any to any connectivity between different companies. Also, you may need to consider deployment services, IT services, etc. SOA architecture enables SOA to meet all life’s priorities. The ESB is part of this reference architecture and provides the backbone of an SOA, but it should not be considered an SOA by itself.
Q10. In SOA, do we need to build a system from scratch?If we need to integrate any existing system, you can only loosely couple wrappers that help wrap all customer services and generically expose all functionalities.
Recommended ArticlesThis has been a guide to the list Of SOA Interview Questions and Answers so that the candidate can crackdown these SOA Interview Questions easily. Here in this post, we have studied top SOA Interview Questions, which are often asked in interviews. You may also look at the following articles to learn more –
Top 100+ Cyber Security Interview Questions And Answers
1) What is cybersecurity?Here are Cyber Security interview questions and answers for fresher as well experienced candidates to get their dream job.
Cybersecurity refers to the protection of hardware, software, and data from attackers. The primary purpose of cyber security is to protect against cyberattacks like accessing, changing, or destroying sensitive information.
2) What are the elements of cybersecurity?Major elements of cybersecurity are:
Information security
Network security
Operational security
Application security
End-user education
Business continuity planning
Benefits of cyber security are as follows:
It protects the business against ransomware, malware, social engineering, and phishing.
It protects end-users.
It gives good protection for both data as well as networks.
Increase recovery time after a breach.
Cybersecurity prevents unauthorized users.
4) Define Cryptography.
5) Differentiate between IDS and IPS.Intrusion Detection System (IDS) detects intrusions. The administrator has to be careful while preventing the intrusion. In the Intrusion Prevention System (IPS), the system finds the intrusion and prevent it.
6) What is CIA?Confidentiality, Integrity, and Availability (CIA) is a popular model which is designed to develop a security policy. CIA model consists of three concepts:
Confidentiality: Ensure the sensitive data is accessed only by an authorized user.
Integrity: Integrity means the information is in the right format.
Availability: Ensure the data and resources are available for users who need them.
7) What is a Firewall?It is a security system designed for the network. A firewall is set on the boundaries of any system or network which monitors and controls network traffic. Firewalls are mostly used to protect the system or network from malware, worms, and viruses. Firewalls can also prevent content filtering and remote access.
8) Explain TracerouteIt is a tool that shows the packet path. It lists all the points that the packet passes through. Traceroute is used mostly when the packet does not reach the destination. Traceroute is used to check where the connection breaks or stops or to identify the failure.
9) Differentiate between HIDS and NIDS.Parameter HIDS NIDS
Usage HIDS is used to detect the intrusions. NIDS is used for the network.
What does it do? It monitors suspicious system activities and traffic of a specific device. It monitors the traffic of all device on the network.
10) Explain SSLSSL stands for Secure Sockets Layer. It is a technology creating encrypted connections between a web server and a web browser. It is used to protect the information in online transactions and digital payments to maintain data privacy.
11) What do you mean by data leakage?Data leakage is an unauthorized transfer of data to the outside world. Data leakage occurs via email, optical media, laptops, and USB keys.
12) Explain the brute force attack. How to prevent it?It is a trial-and-error method to find out the right password or PIN. Hackers repetitively try all the combinations of credentials. In many cases, brute force attacks are automated where the software automatically works to login with credentials. There are ways to prevent Brute Force attacks. They are:
Setting password length.
Increase password complexity.
Set limit on login failures.
13) What is port scanning?It is the technique for identifying open ports and service available on a specific host. Hackers use port scanning technique to find information for malicious purposes.
14) Name the different layers of the OSI model.Seven different layers of OSI models are as follows:
Physical Layer
Data Link Layer
Network Layer
Transport Layer
Session Layer
Presentation Layer
Application Layer
15) What is a VPN?VPN stands for Virtual Private Network. It is a network connection method for creating an encrypted and safe connection. This method protects data from interference, snooping, censorship.
16) What are black hat hackers?Black hat hackers are people who have a good knowledge of breaching network security. These hackers can generate malware for personal financial gain or other malicious reasons. They break into a secure network to modify, steal, or destroy data so that the network can not be used by authorized network users.
17) What are white hat hackers?White hat hackers or security specialist are specialized in penetration testing. They protect the information system of an organization.
18) What are grey hat hackers?Grey hat hackers are computer hacker who sometimes violate ethical standards, but they do not have malicious intent.
19) How to reset a password-protected BIOS configuration?There are various ways to reset BIOS password. Some of them are as follows:
Remove CMOS battery.
By utilizing the software.
By utilizing a motherboard jumper.
By utilizing MS-DOS.
20) What is MITM attack?A MITM or Man-in-the-Middle is a type of attack where an attacker intercepts communication between two persons. The main intention of MITM is to access confidential information.
21) Define ARP and its working process.It is a protocol used for finding MAC address associated with IPv4 address. This protocol work as an interface between the OSI network and OSI link layer.
22) Explain botnet.It’s a number of internet-connected devices like servers, mobile devices, IoT devices, and PCs that are infected and controlled by malware.
23) What is the main difference between SSL and TLS?The main difference between these two is that SSL verifies the identity of the sender. SSL helps you to track the person you are communicating to. TLS offers a secure channel between two clients.
24) What is the abbreviation of CSRF?CSRF stands for Cross-Site Request Forgery.
25) What is 2FA? How to implement it for a public website?TFA stands for Two Factor Authentication. It is a security process to identify the person who is accessing an online account. The user is granted access only after presenting evidence to the authentication device.
26) Explain the difference between asymmetric and symmetric encryption.Symmetric encryption requires the same key for encryption and decryption. On the other hand, asymmetric encryption needs different keys for encryption and decryption.
27) What is the full form of XSS?XSS stands for cross-site scripting.
28) Explain WAF 29) What is hacking?Hacking is a process of finding weakness in computer or private networks to exploit its weaknesses and gain access.
For example, using password cracking technique to gain access to a system.
30) Who are hackers?A Hacker is a person who finds and exploits the weakness in computer systems, smartphones, tablets, or networks to gain access. Hackers are well experienced computer programmers with knowledge of computer security.
31) What is network sniffing?Network sniffing is a tool used for analyzing data packets sent over a network. This can be done by the specialized software program or hardware equipment. Sniffing can be used to:
Capture sensitive data such as password.
Eavesdrop on chat messages
Monitor data package over a network
32) What is the importance of DNS monitoring?Yong domains are easily infected with malicious software. You need to use DNS monitoring tools to identify malware.
33) Define the process of salting. What is the use of salting?Salting is that process to extend the length of passwords by using special characters. To use salting, it is very important to know the entire mechanism of salting. The use of salting is to safeguard passwords. It also prevents attackers testing known words across the system.
For example, Hash(“QxLUF1bgIAdeQX”) is added to each and every password to protect your password. It is called as salt.
34) What is SSH?SSH stands for Secure Socket Shell or Secure Shell. It is a utility suite that provides system administrators secure way to access the data on a network.
35) Is SSL protocol enough for network security?SSL verifies the sender’s identity, but it does not provide security once the data is transferred to the server. It is good to use server-side encryption and hashing to protect the server against a data breach.
36) What is black box testing and white box testing?
Black box testing: It is a software testing method in which the internal structure or program code is hidden.
White box testing: A software testing method in which internal structure or program is known by tester.
37) Explain vulnerabilities in network security.Vulnerabilities refer to the weak point in software code which can be exploited by a threat actor. They are most commonly found in an application like SaaS (Software as a service) software.
38) Explain TCP Three-way handshake.It is a process used in a network to make a connection between a local host and server. This method requires the client and server to negotiate synchronization and acknowledgment packets before starting communication.
39) Define the term residual risk. What are three ways to deal with risk?It is a threat that balances risk exposure after finding and eliminating threats.
Three ways to deal with risk are:
Reduce it
Avoid it
Accept it.
40) Define Exfiltration. 41) What is exploit in network security?An exploit is a method utilized by hackers to access data in an unauthorized way. It is incorporated into malware.
42) What do you mean by penetration testing?It is the process of checking exploitable vulnerabilities on the target. In web security, it is used to augment the web application firewall.
43) List out some of the common cyber-attack.Following are the common cyber-attacks which can be used by hackers to damage network:
Malware
Phishing
Password attacks
DDoS
Man in the middle
Malvertising
Rogue software
44) How to make the user authentication process more secure?In order to authenticate users, they have to provide their identity. The ID and Key can be used to confirm the user’s identity. This is an ideal way how the system should authorize the user.
45) Explain the concept of cross-site scripting.Cross-site scripting refers to a network security vulnerability in which malicious scripts are injected into websites. This attack occurs when attackers allow an untrusted source to inject code into a web application.
46) Name the protocol that broadcast the information across all the devices.Internet Group Management Protocol or IGMP is a communication protocol that is used in game or video streaming. It facilitates routers and other communication devices to send packets.
47) How to protect email messages?Use cipher algorithm to protect email, credit card information, and corporate data.
48) What are the risks associated with public Wi-Fi?Public Wi-Fi has many security issues. Wi-Fi attacks include karma attack, sniffing, war-driving, brute force attack, etc.
Public Wi-Fi may identify data that is passed through a network device like emails, browsing history, passwords, and credit card data.
49) What is Data Encryption? Why it is important in network security?Data encryption is a technique in which the sender converts the message into a code. It allows only authorized user to gain access.
50) Explain the main difference between Diffie-Hellman and RSA.Diffie-Hellman is a protocol used while exchanging key between two parties while RSA is an algorithm that works on the basis two keys called private and public key.
51) What is a remote desktop protocol?Remote Desktop Protocol (RDP) is developed by Microsoft, which provides GUI to connect two devices over a network.
The user uses RDP client software to serve this purpose while other device must run RDP server software. This protocol is specifically designed for remote management and to access virtual PCs, applications, and terminal server.
52) Define Forward Secrecy.Forward Secrecy is a security measure that ensures the integrity of unique session key in event that long term key is compromised.
53) Explain the concept of IV in encryption.IV stands for the initial vector is an arbitrary number that is used to ensures that identical text encrypted to different ciphertexts. Encryption program uses this number only once per session.
54) Explain the difference between stream cipher and block cipher.Parameter Stream Cipher Block Cipher
How does it work? Stream cipher operates on small plaintext units Block cipher works on large data blocks.
Code requirement It requires less code. It requires more code.
Usage of key Key is used only once. Reuse of key is possible.
Application Secure Socket layer. File encryption and database.
Usage Stream cipher is used to implement hardware. Block cipher is used to implement software.
55) Give some examples of a symmetric encryption algorithm.Following are some examples of symmetric encryption algorithm.
RCx
Blowfish
Rijndael (AES)
DES
56) What is the abbreviation of ECB and CBC?The full form of ECB is Electronic Codebook, and the full form of CBC is Cipher Block Chaining.
57) Explain a buffer overflow attack. 58) Define Spyware.Spyware is a malware that aims to steal data about the organization or person. This malware can damage the organization’s computer system.
59) What is impersonation?It is a mechanism of assigning the user account to an unknown user.
60) What do you mean by SRM?SRM stands for Security Reference Monitor provides routines for computer drivers to grant access rights to object.
61) What is a computer virus?A virus is a malicious software that is executed without the user’s consent. Viruses can consume computer resources, such as CPU time and memory. Sometimes, the virus makes changes in other computer programs and insert its own code to harm the computer system.
A computer virus may be used to:
Access private data like user id and passwords
Display annoying messages to the user
Corrupt data in your computer
Log the user’s keystrokes
62) What do you mean by Authenticode?Authenticode is a technology that identifies the publisher of Authenticode sign software. It allows users to ensure that the software is genuine and not contain any malicious program.
63) Define CryptoAPICryptoAPI is a collection of encryption APIs which allows developers to create a project on a secure network.
64) Explain steps to secure web server.Follow the following steps to secure your web server:
Update ownership of file.
Keep your webserver updated.
Disable extra modules in the webserver.
Delete default scripts.
65) What is Microsoft Baseline Security Analyzer?Microsoft Baseline Security Analyzer or MBSA is a graphical and command-line interface that provides a method to find missing security updates and misconfigurations.
66) What is Ethical hacking?Ethical hacking is a method to improve the security of a network. In this method, hackers fix vulnerabilities and weakness of computer or network. Ethical hackers use software tools to secure the system.
67) Explain social engineering and its attacks.Social engineering is the term used to convince people to reveal confidential information.
There are mainly three types of social engineering attacks: 1) Human-based, 2) Mobile-based, and 3) Computer-based.
Human-based attack: They may pretend like a genuine user who requests higher authority to reveal private and confidential information of the organization.
Computer-based attack: In this attack, attackers send fake emails to harm the computer. They ask people to forward such email.
68) What is IP and MAC Addresses?IP Address is the acronym for Internet Protocol address. An internet protocol address is used to uniquely identify a computer or device such as printers, storage disks on a computer network.
MAC Address is the acronym for Media Access Control address. MAC addresses are used to uniquely identify network interfaces for communication at the physical layer of the network.
69) What do you mean by a worm?A Worm is a type of malware which replicates from one computer to another.
70) State the difference between virus and wormParameter Virus Worm
How they infect a computer? It inserts malicious code into a specific file or program. Generate it’s copy and spread using email client.
Dependency Virus need a host program to work They do not require any host to function correctly.
Linked with files It is linked with any file on a network.
Affecting speed It is slower than worm. It faster compared to a virus.
71) Name some tools used for packet sniffing.Following are some tools used for packet sniffing.
Tcpdump
Kismet
Wireshark
NetworkMiner
Dsniff
72) Explain anti-virus sensor systemsAntivirus is software tool that is used to identify, prevent, or remove the viruses present in the computer. They perform system checks and increase the security of the computer regularly.
73) List out the types of sniffing attacks.Various types of sniffing attacks are:
Protocol Sniffing
Web password sniffing
Application-level sniffing
TCP Session stealing
LAN Sniffing
ARP Sniffing
74) What is a distributed denial-of-service attack (DDoS)?It is an attack in which multiple computers attack website, server, or any network resource.
75) Explain the concept of session hijacking.TCP session hijacking is the misuse of a valid computer session. IP spoofing is the most common method of session hijacking. In this method, attackers use IP packets to insert a command between two nodes of the network.
76) List out various methods of session hijacking.Various methods of session hijacking are:
Using packet Sniffers
Cross-Site Scripting (XSS Attack)
IP Spoofing
Blind Attack
77) What are Hacking Tools?Hacking Tools are computer programs and scripts that help you find and exploit weaknesses in computer systems, web applications, servers, and networks. There are varieties of such tools available on the market. Some of them are open source, while others are a commercial solution.
78) Explain honeypot and its Types.Honeypot is a decoy computer system which records all the transactions, interactions, and actions with users.
Honeypot is classified into two categories: 1) Production honeypot and 2) Research honeypot.
Production honeypot: It is designed to capture real information for the administrator to access vulnerabilities. They are generally placed inside production networks to increase their security.
Research Honeypot: It is used by educational institutions and organizations for the sole purpose of researching the motives and tactics of the back-hat community for targeting different networks.
79) Name common encryption tools.Tools available for encryptions are as follows:
RSA
Twofish
AES
Triple DES
80) What is Backdoor?It is a malware type in which security mechanism is bypassed to access a system.
81) Is it right to send login credentials through email?It is not right to send login credentials through email because if you send someone userid and password in the mail, chances of email attacks are high.
82) Explain the 80/20 rule of networking?This rule is based on the percentage of network traffic, in which 80% of all network traffic should remain local while the rest of the traffic should be routed towards a permanent VPN.
83) Define WEP cracking.It is a method used for a security breach in wireless networks. There are two types of WEP cracking: 1) Active cracking and 2) Passive cracking.
84) What are various WEP cracking tools?Well known WEP cracking tools are:
Aircrack
WebDecrypt
Kismet
WEPCrack
85) What is a security auditing?Security auditing is an internal inspection of applications and operating systems for security flaws. An audit can also be done via line by line inspection of code.
86) Explain phishing.It is a technique used to obtain a username, password, and credit card details from other users.
87) What is Nano-scale encryption?Nano encryption is a research area which provides robust security to computers and prevents them from hacking.
88) Define Security Testing?Security Testing is defined as a type of Software Testing that ensures software systems and applications are free from any vulnerabilities, threats, risks that may cause a big loss.
89) Explain Security Scanning.Security scanning involves identifying network and system weaknesses and later provides solutions for reducing these risks. This scanning can be performed for both Manual as well as Automated scanning.
90) Name the available hacking tools.Following is a list of useful hacking tools.
Acunetix
WebInspect
Probably
Netsparker
Angry IP scanner:
Burp Suite
Savvius
91) What is the importance of penetration testing in an enterprise?Here are two common application of Penetration testing.
Financial sectors like stock trading exchanges, investment banking, want their data to be secured, and penetration testing is essential to ensure security.
In case if the software system is already hacked and the organization would like to determine whether any threats are still present in the system to avoid future hacks.
Penetration testing cannot find all vulnerabilities in the system.
There are limitations of time, budget, scope, skills of penetration testers.
Data loss and corruption
Down Time is high which increase costs
93) Explain security threatSecurity threat is defined as a risk which can steal confidential data and harm computer systems as well as organization.
94) What are physical threats?A physical threat is a potential cause of an incident that may result in loss or physical damage to the computer systems.
95) Give examples of non-physical threatsFollowing are some examples of non-physical threat:
Loss of sensitive information
Loss or corruption of system data
Cyber security Breaches
Disrupt business operations that rely on computer systems
Illegal monitoring of activities on computer systems
96) What is Trojan virus?Trojan is a malware employed by hackers and cyber-thieves to gain access to any computer. Here attackers use social engineering techniques to execute the trojan on the system.
97) Define SQL InjectionIt is an attack that poisons malicious SQL statements to database. It helps you to take benefit of the design flaws in poorly designed web applications to exploit SQL statements to execute malicious SQL code. In many situations, an attacker can escalate SQL injection attack in order to perform other attack, i.e. denial-of-service attack.
98) List security vulnerabilities as per Open Web Application Security Project (OWASP).Security vulnerabilities as per open web application security project are as follows:
SQL Injection
Cross-site request forgery
Insecure cryptographic storage
Broken authentication and session management
Insufficient transport layer protection
Unvalidated redirects and forwards
Failure to restrict URL access
99) Define an access token.An access token is a credential which is used by the system to check whether the API should be granted to a particular object or not.
100) Explain ARP PoisoningARP (Address Resolution Protocol) Poisoning is a type of cyber-attack which is used to convert IP address to physical addresses on a network device. The host sends an ARP broadcast on the network, and the recipient computer responds back with its physical address.
ARP poisoning is sending fake addresses to the switch so that it can associate the fake addresses with the IP address of a genuine computer on a network and hijack the traffic.
101) Name common types of non-physical threats.Following are various types of non-physical threats:
Trojans
Adware
Worms
Spyware
Denial of Service Attacks
Distributed Denial of Service Attacks
Virus
Key loggers
Unauthorized access to computer systems resources
Phishing
102) Explain the sequence of a TCP connection.The sequence of a TCP connection is SYN-SYN ACK-ACK.
103) Define hybrid attacks.Hybrid attack is a blend of dictionary method and brute force attack. This attack is used to crack passwords by making a change of a dictionary word with symbols and numbers.
104) What is Nmap?Nmap is a tool which is used for finding networks and in security auditing.
105) What is the use of EtterPeak tool?EtterPeak is a network analysis tool that is used for sniffing packets of network traffic.
106) What are the types of cyber-attacks?There are two types of cyberattacks: 1) Web-based attacks, 2) System based attacks.
107) List out web-based attacksSome web-based attacks are: 1) SQL Injection attacks, 2) Phishing, 3) Brute Force, 4) DNS Spoofing, 4) Denial of Service, and 5) Dictionary attacks.
108) Give examples of System-based attacksExamples of system-based attacks are:
Virus
Backdoors
Bots
Worm
109) List out the types of cyber attackersThere are four types of cyber attackers. They are: 1) cybercriminals, 2) hacktivists, 3) insider threats, 4) state-sponsored attackers.
110) Define accidental threatsThey are threats that are accidently done by organization employees. In these threats, an employee unintentionally deletes any file or share confidential data with outsiders or a business partner going beyond the policy of the company.
These interview questions will also help in your viva(orals)
Top 6 Sql Joins Interview Questions And Answers {Updated For 2023}
Introduction To SQL Joins Interview Questions And Answers
SQL refer as Structured Query Language is a language that is designed entirely for accessing databases, and it is the most popular with other Database languages. With SQL, we can create tables, change data, update, and delete as per the business requirement. So, let’s start with the frequently asked SQL joins interview questions.
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Below is the important set of SQL Joins Interview Questions that are divided into two-part:
Part 1 – SQL Joins Interview Questions(Basic)The first part covers the basic interview questions:
1. What is a SQL join and why do we need it?SQL joins are used to combine records from two or more than two tables in a database system. A join refers to combining the fields from two or more than two tables by using a value that is common to each of the tables which helps in reducing the repeated columns and data stored in columns of the same table. We need joins to get details about the referenced data and It creates a logical bonding between two or more tables. It is necessary to get data efficiently from multiple tables, that’s why we need SQL joins.
2. What are the different types of SQL joins? Give a brief introduction to them?There are total 5 joins in SQL, they are: –
a. Inner Join OR Join
This is a kind of join where we get all the records that match the condition in two or more than two tables and then the records in all the tables that didn’t match are not displayed. It displays only the matching entries of two or more tables.
b. Outer Join
If there are no matching columns then it will return NULL values.
This kind of JOIN combines Right Outer Join in addition to Left Outer Join. It displays records from the tables when the conditions are met and displays the NULL value when there is no match.
This kind of join has two conditions, first, it removes duplicates records from the result, and second this join will be made on all the columns with the same name for equality.
This kind of join gives the cartesian product of the two or more than two tables involved.
It is almost the same as the inner join but rather it is a join of a table to itself.
3. What are Nested Joins in SLQ?This kind of join works for each tuple in the outer join relation, then it scans the entire inner-join relation and adds any tuple that matches the join-condition and the result will be displayed.
Part 2 – SQL Joins Interview Questions (Advanced) 4. What is Merge Join in SQL? 5. What is a hash Join in SQL? how to use it?The below query is an example of a hash join: –
ORDER BY p.Name, ps. Name
6. How data should be structured to perform Join Operations in a one-to-many relationship and what about a many-to-many relationship?Generally, one-to-many relationships are structured using a single FOREIGNKEY. Consider our example of customers and orders above:
CREATE TABLE customers ( customer_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, first_name VARCHAR(255) NOT NULL, last_name VARCHAR(255) NOT NULL, email VARCHAR(255) NOT NULL, ); CREATE TABLE orders ( order_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, customer_id INT NOT NULL, order_placed_date DATE NOT NULL, FOREIGN KEY (customer_id) REFERENCES customers (customer_id) );The answer: we use an intermediary mapping table with two FOREIGN KEYs. Consider the following:
CREATE TABLE orders ( order_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, order_placed_date DATE NOT NULL, ); CREATE TABLE products ( product_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, name VARCHAR(255) NOT NULL, price INT NOT NULL ); CREATE TABLE products_to_orders ( product_to_order_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, order_id INT NOT NULL, product_id INT NOT NULL, FOREIGN KEY (order_id) REFERENCES orders(order_id), FOREIGN KEY (product_id) REFERENCES products(product_id) );In this example, we need to use two JOIN statements to link all these tables together: one to link products_to_orders to products, and one to link products_to_orders with orders.
Recommended ArticleWe hope that this EDUCBA information on “SQL Joins Interview Questions” was beneficial to you. You can view EDUCBA’s recommended articles for more information.
Top 20 Apache Oozie Interview Questions
This article was published as a part of the Data Science Blogathon.
IntroductionApache Oozie is a Hadoop workflow scheduler. It is a system that manages the workflow of dependent tasks. Users can design Directed Acyclic Graphs of workflows that can be run in parallel and sequentially in Hadoop.
Apache Oozie is an important topic in Data Engineering, so we shall discuss some Apache Oozie interview questions and answers. These questions and answers will help you prepare for Apache Oozie and Data Engineering Interviews.
Read more about Apache Oozie here.
Interview Questions on Apache Oozie1. What is Oozie?
Oozie is a Hadoop workflow scheduler. Oozie allows users to design Directed Acyclic Graphs of workflows, which can then be run in Hadoop in parallel or sequentially. It can also execute regular Java classes, Pig operations, and interface with HDFS. It can run jobs both sequentially and concurrently.
2. Why do we need Apache Oozie?
Apache Oozie is an excellent tool for managing many tasks. There are several sorts of jobs that users want to schedule to run later, as well as tasks that must be executed in a specified order. Apache Oozie can make these types of executions much easier. Using Apache Oozie, the administrator or user can execute multiple independent jobs in parallel, run the jobs in a specific sequence, or control them from anywhere, making it extremely helpful.
3. What kind of application is Oozie?
Oozie is a Java Web App that runs in a Java servlet container.
4. What exactly is an application pipeline in Oozie?
It is important to connect workflow jobs that run regularly but at various times. Multiple successive executions of a process become the input to the following workflow. When these procedures are chained together, the outcome is referred to as a data application pipeline.
5. What is a Workflow in Apache Oozie?
Apache Oozie Workflow is a set of actions that include Hadoop MapReduce jobs, Pig jobs, and so on. The activities are organized in a control dependency DAG (Direct Acyclic Graph) that governs how and when they can be executed. hPDL, an XML Process Definition Language, defines Oozie workflows.
6. What are the major elements of the Apache Oozie workflow?
The Apache Oozie workflow has two main components.
Control flow nodes: These nodes are used to define the start and finish of the workflow, as well as to govern the workflow’s execution path.
Action nodes are used to initiate the processing or calculation task. Oozie supports Hadoop MapReduce, Pig, and File system operations and system-specific activities like HTTP, SSH, and email.
7. What are the functions of the Join and Fork nodes in Oozie?
In Oozie, the fork and join nodes are used in tandem. The fork node divides the execution path into multiple concurrent paths. The join node combines two or more concurrent execution routes into one. The join node’s descendants are the fork nodes that connect concurrently to form join nodes.
Syntax:
…
…
8. What are the various control nodes in the Oozie workflow?
The various control nodes are:
Start
End
Kill
Decision
Fork & Join Control nodes
9. How can I set the start, finish, and error nodes for Oozie?
This can be done in the following Syntax:<error
“[A custom message]”
10. What exactly is an application pipeline in Oozie?
It is important to connect workflow jobs that run regularly but at various times. Multiple successive executions of a process become the input to the following workflow. When these procedures are chained together, the outcome is referred to as a data application pipeline.
11. What are Control Flow Nodes?
The mechanisms that specify the beginning and end of the process are known as control flow nodes (start, end, fail). Furthermore, control flow nodes give way for controlling the workflow’s execution path (decision, fork, and join)
12. What are Action Nodes?
The mechanisms initiating the execution of a computation/processing task are called action nodes. Oozie supports a variety of Hadoop actions out of the box, including Hadoop MapReduce, Hadoop file system, Pig, and others. In addition, Oozie supports system-specific jobs such as SSH, HTTP, email, and so forth.
13. Are Cycles supported by Apache Oozie Workflow?
Apache Oozie Workflow does not support cycles. Workflow definitions in Apache Oozie must be a strict DAG. If Oozie detects a cycle in the workflow specification during workflow application deployment, the deployment is aborted.
14. What is the use of the Oozie Bundle?
The Oozie bundle enables the user to run the work in batches. Oozie bundle jobs are started, halted, suspended, restarted, re-run, or killed in batches, giving you more operational control.
15. How does a pipeline work in Apache Oozie?
The pipeline in Oozie aids in integrating many jobs in a workflow that runs regularly but at different intervals. The output of numerous workflow executions becomes the input of the next planned task in the workflow, which is conducted back to back in the pipeline. The connected chain of workflows forms the Oozie pipeline of jobs.
16. Explain the role of the Coordinator in Apache Oozie?
To resolve trigger-based workflow execution, the Apache Oozie coordinator is employed. It provides a basic framework for providing triggers or predictions, after which it schedules the workflow depending on those established triggers. It enables administrators to monitor and regulate workflow execution in response to cluster conditions and application-specific constraints.
17. What is the decision node’s function in Apache Oozie?
Switch statements are decision nodes that conduct different jobs dependent on the conclusion of another expression.
18. What are the various control flow nodes offered by Apache Oozie workflows for starting and terminating the workflow?
The following control flow nodes are supported by Apache Oozie workflow and start or stop workflow execution.
End Control Node – The end node is the last node to which an Oozie workflow task transfers, which signifies that the workflow job was completed. When a workflow task reaches the end node, it completes, and the job status switches to SUCCEED. One end node is required for every Apache Oozie workflow definition.
The kill control node allows a workflow job to kill itself. When a workflow task reaches the kill node, it terminates in error, and the job status switches to KILLED.
19. What are the various control flow nodes that Apache Oozie workflows offer for controlling the workflow execution path?
The following control flow nodes are supported by Apache Oozie workflow and control the workflow’s execution path.
Decision Control Node – A decision control node is similar to a switch-case statement because it allows a process to choose which execution path to take.
Fork and Join Control Nodes – The fork and join control nodes work in pairs and function as follows. The fork node divides a single execution path into numerous concurrent execution paths. The join node waits until all concurrent execution paths from the relevant fork node arrive.
20. What is the default database Oozie uses to store job ids and statuses?
Oozie stores job ids and job statuses in the Derby database.
ConclusionThese Apache Oozie Interview Questions can assist you in becoming interview-ready for your upcoming personal interview. In Oozie-related interviews, interviewers usually ask the interviewee these .
To sum up:
Apache Oozie is a distributed scheduling system to launch and manage Hadoop tasks.
Oozie allows you to combine numerous complex jobs that execute in a specific order to complete a larger task.
Two or more jobs within a specific set of tasks can be programmed to execute in parallel with Oozie.
The real reason for adopting Oozie is to manage various types of tasks that are being handled in the Hadoop system. The user specifies various dependencies between jobs in the form of a DAG. This information is consumed by Oozie and handled in the order specified in the workflow. This saves the user time when managing the complete workflow. Oozie also determines the frequency at which a job is executed.
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Top 10 Redux Interview Questions & Answers {Updated For 2023}
Introduction to Redux Interview Questions and Answers
React is a User interface library. The core Redux is built upon action, state, and reducers. All the data resides at the store. Reacts components use actions in order to update the stores. Reducers help the store to update itself. Props make sure the updated stores are available for the React.
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Now Redux is a knowable state container built for JavaScript apps. It allows managing the application state, and it stands to be open source. Applications that run consistently help run in different environments (client, server, and native) and are easy to test.
Now, if you are looking for a job related to Redux, you need to prepare for the 2023 Redux Interview Questions. Every interview is different from the different job profiles, but still, to clear the interview, you need to have a good and clear knowledge of Redux. Here, we have prepared the important Redux Interview Questions And Answers which will help you succeed in your interview.
Below are the 10 important Redux Interview Questions And Answers that are frequently asked in an interview. These questions are divided into two parts are as follows:
Part 1 – Redux Interview Questions (Basic)This first part covers basic Interview Questions and Answers.
1. Benefits of Redux?Answer:
Maintainability: The maintenance of Redux becomes easier due to strict code structure and organization.
Organization: code organization is very strict; hence the stability of the code is high, which intern increases the work to be much easier.
Server rendering: This is useful, particularly to the preliminary render, which keeps up a better user experience or search engine optimization. The server-side created stores are forwarded to the client-side.
Developer tools: It is Highly traceable, so changes in position and changes in the application; all such instances make the developers have a real-time experience.
Ease of testing: The first rule of writing testable code is to write small functions that do only one thing and that are independent. Redux’s code is made of functions that used to be: small, pure, and isolated.
Q2. How Distinct from MVC and Flux?As far as MVC structure is concerned, the data, presentation, and logical layers are well separated and handled. Change to an application even at a smaller position may involve many changes through the application. this happens because data flow exists bidirectional as far as MVC is concerned. Maintenance of MVC structures are hardly complex, and Debugging also expects a lot of experience for it.
Q3. Functional programming concepts?The various functional programming concepts used to structure Redux are listed below,
Functions are treated as First-class objects.
Capable of passing functions in the format of arguments.
Capable of controlling flow using recursions, functions, and arrays.
Helper functions such as reduce and map filters are used.
Allows linking functions together.
The state doesn’t change.
Prioritize the order of executing the code is not really necessary.
Q4. Redux change of state?Example:
A function is called in the form of a component.
So now an action gets dispatched by the relative container.
This happens because the prop (which was just called in the container) is tied to an action dispatcher using mapDispatchToProps (in the container).
Reducer on capturing the action, it intern executes a function, and this function returns a new state with specific changes.
The state change is known by the container and modifies a specific prop in the component due to the mapStateToProps function.
Q5. Where can Redux be used?Redux is majorly used in combination with reacting. It also has the ability to get used to other view libraries too. Some of the famous entities like AngularJS, chúng tôi and Meteor. It can get combined with Redux easily. This is a key reason for the popularity of Redux in its ecosystem. So many articles, tutorials, middleware, tools, and boilerplates are available.
Part 2 – Redux Interview Questions (Advanced) Q6. What is the typical flow of data in a React + Redux app?Call-back from the UI component dispatches an action with a payload; these dispatched actions are intercepted and received by the reducers. This interception will generate a new application state. From here, the actions will be propagated down through a hierarchy of components from the Redux store. The below diagram depicts the entity structure of a redux+react setup.
Q7. What is store in redux?ducers return a state via action.
export function configureStore(initialState) { return createStore(rootReducer, initialState); }The root reducer is a collection of all reducers in the application.
const rootReducer = combineReducers({ donors: donorReducer, }); Q8. Explain Reducers in Redux?The reducer as follows.
export default function donorReducer(state = [], action) { switch (action.type) { case actionTypes.addDonor: return [...state, action.donor]; default: return state; } }The reducers receive the initial state and action. Based on the action type, it returns a new state for the store. The state maintained by reducers is immutable. The below-given reducer it holds the current state and action as an argument for it and then returns the next.
state:function handelingAuthentication(st, actn) { return _.assign({}, st, { auth: actn.pyload }); } Q9. Redux workflow features?Answer:
Reset: Allow to reset the state of the store
Revert: Rollback to the last committed state
Sweep: All disabled actions that you might have fired by mistake will be removed
Commit: Makes the current state the initial state
Q10. Explain action’s in Redux?Actions in Redux are functions that return an action object. The action-type and the action data are packed in the action object. Which also allows a donor to be added to the system. Actions send data between the store and the application. The actions produce all information retrieved by the store.
export function addDonorAction(donor) { return { type: actionTypes.addDonor, donor, }; }Internal Actions are built on top of Javascript objects and associate a type of property to it.
Recommended ArticleThis has been a guide to List Of Redux Interview Questions and Answers so that the candidate can crackdown these Interview Questions easily. Here in this post, we have studied about top Redux Interview Questions, which are often asked in interviews. You may also look at the following articles to learn more –
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