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AT&T Interview Questions and Answers
41 Interview questions
JDK is for development, JRE is for running Java applications, and JVM is the engine that executes Java bytecode.
JDK (Java Development Kit): A full-featured software development kit that includes tools for developing, debugging, and monitoring Java applications. Example: javac compiler.
JRE (Java Runtime Environment): A subset of the JDK that provides the libraries and components necessary to run Java applications. ...
OOP concepts in Java include Encapsulation, Inheritance, Polymorphism, and Abstraction, enabling modular and reusable code.
Encapsulation: Bundling data and methods that operate on the data within one unit (class). Example: private variables with public getters/setters.
Inheritance: Mechanism where one class inherits properties and behaviors from another. Example: class Dog extends Animal.
Polymorphism: Ability to pr...
Data warehouses, data marts, data lakes, and delta lakes serve different purposes in data storage and analytics.
Data Warehouse: Centralized repository for structured data, optimized for query and analysis. Example: Amazon Redshift.
Data Mart: Subset of a data warehouse focused on a specific business line or team. Example: Sales data mart.
Data Lake: Storage for raw, unstructured data, allowing for flexible data expl...
Denormalization in OLAP systems improves query performance by reducing the complexity of data retrieval.
Denormalization reduces the number of joins needed in queries, speeding up data retrieval.
In OLAP, data is often read-heavy; denormalized structures like star schemas optimize read performance.
For example, a star schema combines fact tables with dimension tables, simplifying queries.
Denormalization can lead to d...
Compensation and benefits include salary, bonuses, health insurance, retirement plans, and other perks.
Base Salary: The fixed annual amount paid to an employee, e.g., $100,000.
Bonuses: Performance-based incentives, e.g., annual bonuses up to 20% of salary.
Health Insurance: Coverage for medical expenses, e.g., employer pays 80% of premiums.
Retirement Plans: Contributions to 401(k) or pension plans, e.g., employer m...
CLR stands for Common Language Runtime, a virtual machine component of the .NET framework responsible for managing code execution.
CLR provides services such as memory management, exception handling, and security.
It compiles code into Intermediate Language (IL) and then translates it into machine code at runtime.
CLR allows for language interoperability within the .NET framework, enabling different languages to work...
Static keyword in Java is used to create class-level variables and methods that can be accessed without creating an instance of the class.
Static variables are shared among all instances of a class.
Static methods can be called without creating an object of the class.
Static keyword can be used to initialize a variable only once.
Example: public static int count = 0;
Streams process elements sequentially, while parallel streams process elements concurrently.
Streams process elements one by one in a sequential manner.
Parallel streams process elements concurrently, potentially utilizing multiple threads for faster processing.
Streams are suitable for smaller datasets or when order matters.
Parallel streams are more efficient for larger datasets or when order is not important.
Exampl...
Using Unix command 'grep' to find a word in a set of files
Use 'grep' command followed by the word you want to search for and the file(s) you want to search in
Add the '-r' flag to search recursively in all files in a directory
Use '-i' flag for case-insensitive search
Example: grep 'hello' file.txt
Example: grep -r 'error' /path/to/directory
Example: grep -i 'apple' file1.txt file2.txt
To pull large amount of data in Spring Data JPA, use pagination, lazy loading, and query optimization techniques.
Use pagination to limit the amount of data retrieved in each query
Implement lazy loading to fetch data only when needed
Optimize queries by using indexes, avoiding N+1 query problem, and fetching only necessary columns
AT&T Interview Experiences
59 interviews found
Anonymous
I appeared for an interview in Dec 2024.
(3 Questions)
- Q1. What is Object-Oriented Programming (OOP), and can you explain its fundamental concepts?
- Ans.
OOP is a programming paradigm based on the concept of objects, which can contain data in the form of fields and code in the form of procedures.
OOP focuses on creating objects that interact with each other to solve complex problems.
Fundamental concepts include classes, objects, inheritance, encapsulation, and polymorphism.
Classes are blueprints for creating objects, while objects are instances of classes.
Inheritance all...
- Q2. What is the definition of an array, and what are the different types of arrays?
- Ans.
An array is a data structure that stores a collection of elements of the same type. There are different types of arrays such as one-dimensional, multi-dimensional, and associative arrays.
One-dimensional array: Stores elements in a single row or column.
Multi-dimensional array: Stores elements in multiple rows and columns.
Associative array: Uses key-value pairs to store elements.
Example: ['apple', 'banana', 'orange']
- Q3. What is the clr
- Ans.
CLR stands for Common Language Runtime, a virtual machine component of the .NET framework responsible for managing code execution.
CLR provides services such as memory management, exception handling, and security.
It compiles code into Intermediate Language (IL) and then translates it into machine code at runtime.
CLR allows for language interoperability within the .NET framework, enabling different languages to work toge...
The content is based on HTML, Windows, and ADO.NET.
(2 Questions)
- Q1. What motivates you to pursue this job?
- Ans.
I am motivated to pursue a career as a Customer Care Executive because I enjoy helping others and providing excellent service.
I have a passion for assisting customers and resolving their issues
I thrive in a fast-paced environment where I can use my communication skills effectively
I find satisfaction in ensuring customer satisfaction and building positive relationships
I believe in the importance of delivering exceptiona...
- Q2. What is your expected salary?
- Ans.
My expected salary is based on my experience, skills, and the market rate for web developers.
I have researched the average salary for web developers in this location.
I am open to negotiation based on the overall compensation package offered.
I am looking for a salary that reflects my expertise and contributions to the team.
I applied via Approached by Company and was interviewed in Dec 2024. There were 3 interview rounds.
Request to write procedures for React, Node, and MySQL.
Discussed the terminologies related to the job position, such as securing data and handling large datasets.
(2 Questions)
- Q1. What is your reason for seeking a change in your current position?
- Ans.
Seeking new challenges and opportunities for growth in a more specialized role.
Desire to work on more complex projects
Opportunity to specialize in a specific technology or domain
Seeking career advancement and professional development
Looking for a more challenging and rewarding role
- Q2. What is the reason for your job changes approximately every 2.5 years?
- Ans.
Seeking new challenges and opportunities for growth led to job changes every 2.5 years.
Desire for new challenges and opportunities for growth
Seeking higher compensation or better benefits
Company restructuring or layoffs
Relocation or family reasons
Exploring different industries or technologies
Interview Preparation Tips
I applied via Referral and was interviewed in Oct 2024. There was 1 interview round.
(2 Questions)
- Q1. It was a online coding round with one question related to a medium hard binary search question..
- Q2. The second question was bit ambiguous question involving a tree, where we were asked to add a tree child and subchild in the form a a directory and subdirectory
- Ans.
Adding a tree child and subchild resembles creating directories and subdirectories in a file system.
A tree structure consists of nodes, where each node can have multiple children.
To add a child, create a new node and link it to the parent node.
For example, if 'Folder A' is a parent, 'Folder B' can be a child of 'Folder A'.
To add a subchild, link a new node to the child node, e.g., 'File 1' as a subchild of 'Folder B'.
T...
Interview Preparation Tips
I appeared for an interview in May 2025, where I was asked the following questions.
- Q1. SQL - easy/ medium aggregation based queries Python - list comprehension Databases - deep dive into OLAP dbs and data formats like AVRO, PARQUET Deep dive on points mentioned in resume. Overall 4 rounds - ...
- Q2. There might be offsite rounds
Selected
I applied via Referral and was interviewed in Aug 2024. There were 3 interview rounds.
(2 Questions)
- Q1. Ospf protocol and routing
- Q2. Osi layers and bgp
(2 Questions)
- Q1. Bgp protocol and switching
- Q2. Incident management
(2 Questions)
- Q1. Tell me about yourself
- Ans.
I am a highly experienced Senior Network Engineer with a strong background in designing, implementing, and managing complex network infrastructures.
Over 10 years of experience in network engineering
Proficient in Cisco, Juniper, and Palo Alto technologies
Skilled in network design, implementation, and troubleshooting
Certified in CCNP and JNCIP
Led successful network upgrade projects at previous companies
- Q2. Experience and expertice , certification
Chandra Sekhar Mahanta
Selected
Automation scripting and test management.
How will you manage escalations with a third-party vendor?
(3 Questions)
- Q1. What is the breakdown of compensation and benefits?
- Ans.
Compensation and benefits include salary, bonuses, health insurance, retirement plans, and other perks.
Base Salary: The fixed annual amount paid to an employee, e.g., $100,000.
Bonuses: Performance-based incentives, e.g., annual bonuses up to 20% of salary.
Health Insurance: Coverage for medical expenses, e.g., employer pays 80% of premiums.
Retirement Plans: Contributions to 401(k) or pension plans, e.g., employer matche...
- Q2. Location preferences
- Q3. Reduce notice period in previous company
Interview Preparation Tips
I applied via LinkedIn and was interviewed in Jun 2024. There was 1 interview round.
(3 Questions)
- Q1. Sql question related to windows function
- Q2. Unix basics - find a word in a set of files
- Ans.
Using Unix command 'grep' to find a word in a set of files
Use 'grep' command followed by the word you want to search for and the file(s) you want to search in
Add the '-r' flag to search recursively in all files in a directory
Use '-i' flag for case-insensitive search
Example: grep 'hello' file.txt
Example: grep -r 'error' /path/to/directory
Example: grep -i 'apple' file1.txt file2.txt
- Q3. Python question related to file system, regex
Interview Preparation Tips
Skills evaluated in this interview
Selected
I appeared for an interview in Mar 2025, where I was asked the following questions.
- Q1. Tell me about your self.
- Q2. Why do you join this company.
- Q3. What is Oops concepts in java.
- Q4. What are the main features of java.
- Q5. What is the difference between JDK, JRE, AND JVM.
Skills evaluated in this interview
(2 Questions)
- Q1. Difference between streams and parallel streams
- Ans.
Streams process elements sequentially, while parallel streams process elements concurrently.
Streams process elements one by one in a sequential manner.
Parallel streams process elements concurrently, potentially utilizing multiple threads for faster processing.
Streams are suitable for smaller datasets or when order matters.
Parallel streams are more efficient for larger datasets or when order is not important.
Example: St...
- Q2. What is Static keyword in Java do?
- Ans.
Static keyword in Java is used to create class-level variables and methods that can be accessed without creating an instance of the class.
Static variables are shared among all instances of a class.
Static methods can be called without creating an object of the class.
Static keyword can be used to initialize a variable only once.
Example: public static int count = 0;
Interview Preparation Tips
Skills evaluated in this interview
(2 Questions)
- Q1. Past Projects achievements
- Ans.
Led cross-functional teams to successfully deliver multiple projects on time and within budget.
Managed project timelines, resources, and budgets effectively
Implemented project management best practices to ensure successful outcomes
Collaborated with stakeholders to define project scope and objectives
Resolved project issues and risks in a timely manner
Delivered regular project updates to senior leadership
- Q2. Ai today and tomorrow
Interview Preparation Tips
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