30+ Senior Member Technical Interview Questions and Answers

Docker is a containerization platform while Virtual Machine is a virtualization platform.

• Docker shares the host OS kernel while VM has its own OS.

• Docker is lightweight and faster to start than VM.

• Docker containers are portable and can run on any system with Docker installed.

• VMs are more secure as they provide complete isolation from the host system.

• Docker is ideal for microservices architecture while VMs are better for running multiple applications with different OS requireme...read more

String Pool is a cache of String objects. Strings are immutable because their values cannot be changed once created.

• String Pool is a memory area where Java stores String objects to save memory.

• When a new String is created, Java first checks if it already exists in the String Pool. If it does, it returns a reference to the existing object instead of creating a new one.

• Strings are immutable because any operation that modifies a String actually creates a new String object rather...read more

Optimizing SQL queries can improve performance and reduce resource usage.

• Use indexes to speed up data retrieval

• Avoid using SELECT * and instead specify only required columns

• Use JOINs instead of subqueries

• Avoid using functions in WHERE clauses

• Use UNION ALL instead of UNION if possible

• Avoid using temporary tables

• Use EXPLAIN to analyze query performance

ADP is a global provider of cloud-based human capital management solutions that streamline HR, payroll, talent, time, tax and benefits administration.

• ADP provides software and services related to human resource management, payroll processing, tax compliance, and benefits administration

• It offers cloud-based solutions for businesses of all sizes

• ADP's domain is human capital management

• It serves clients in over 140 countries worldwide

• Some of its popular products include ADP Workf...read more

Functional interfaces are interfaces with only one abstract method. Example: java.util.function.Consumer

• Functional interfaces are used in lambda expressions and method references

• They provide a way to pass behavior as an argument to a method

• Examples include java.util.function.Predicate, java.util.function.Supplier

• Functional interfaces can also have default and static methods

Explanation of differences between List and ArrayList, HashMap behavior with same key, Spring boot beans, Profile annotation in Spring, database configurations in pom.xml, and data structures.

• List is an interface while ArrayList is a class that implements List interface

• HashMap replaces the old value with the new value if the same key is added

• Spring boot beans can be avoided by using @Lazy annotation

• Profile annotation in Spring allows defining different configurations for diff...read more

Linked List allows dynamic size, efficient insertion/deletion, while Array List has faster access and better cache locality.

• Linked List can grow or shrink dynamically, while Array List has fixed size.

• Insertion and deletion are faster in Linked List as it requires only changing pointers, while Array List requires shifting elements.

• Linked List has better memory utilization as it only allocates memory when needed, while Array List pre-allocates memory.

• Array List has faster acces...read more

An API is a set of rules and protocols that allows different software applications to communicate with each other.

• API stands for Application Programming Interface

• It defines the methods and data formats that applications can use to request and exchange information

• APIs can be used to access services or data from other applications or platforms

• Examples include Google Maps API for integrating maps into a website, Twitter API for accessing tweets, and Spotify API for music streami...read more

Abstract class can have both abstract and non-abstract methods, while interface can only have abstract methods.

• Abstract class can have constructors, fields, and methods, while interface cannot have any implementation.

• A class can implement multiple interfaces but can only inherit from one abstract class.

• Abstract classes are used to define a common base class for related classes, while interfaces are used to define a contract for classes to implement.

• Example: Abstract class 'Sh...read more

The web works by using a client-server model where clients request and receive information from servers via the internet.

• Clients (such as web browsers) send requests for web pages or resources to servers

• Servers process these requests and send back the requested information

• HTTP (Hypertext Transfer Protocol) is commonly used for communication between clients and servers

• Web pages are typically written in HTML (Hypertext Markup Language) and styled with CSS (Cascading Style Sheet...read more

Monolith has simplicity but lacks scalability, while microservices offer flexibility but introduce complexity.

• Monolith: Simplicity in development and deployment, easier to debug and test

• Monolith: Lack of scalability, all components tightly coupled

• Microservices: Flexibility to use different technologies for different services

• Microservices: Scalability, each service can be independently scaled

• Microservices: Increased complexity in managing multiple services and communication be...read more

Find the second highest occurrence of a vowel in a string.

• Iterate through the string and count the occurrences of each vowel (a, e, i, o, u).

• Store the counts in an array and find the second highest count.

• Return the vowel with the second highest count.

SDLC process for HR ERP implementation involves planning, analysis, design, development, testing, deployment, and maintenance.

• Planning phase involves defining project scope, goals, and objectives.

• Analysis phase involves gathering requirements and analyzing existing systems.

• Design phase involves creating a blueprint for the new system.

• Development phase involves coding and building the system.

• Testing phase involves testing the system for bugs and errors.

• Deployment phase involve...read more

Solve a simple problem involving arrays, focusing on basic operations and manipulations.

• Identify the problem: Understand what needs to be achieved with the array.

• Common operations: Sorting, searching, or modifying elements.

• Example: Given an array of strings, sort them alphabetically.

• Edge cases: Consider empty arrays or arrays with duplicate strings.

There are 7 layers in the OSI model: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

• Physical layer deals with physical connections and signals

• Data Link layer handles error detection and correction

• Network layer routes data between different networks

• Transport layer ensures data delivery and error checking

• Session layer establishes, maintains, and terminates connections

• Presentation layer translates data into a format that the application layer can...read more

Resources are tools or assets used to achieve a goal, while styles refer to the way in which something is done or presented.

• Resources can include materials, equipment, personnel, or financial assets.

• Styles can encompass different approaches, methods, techniques, or aesthetics.

• For example, in software development, resources may include programming languages and libraries, while styles may refer to coding conventions and design patterns.

An abstract class is a class that cannot be instantiated and may contain abstract methods.

• Cannot be instantiated directly

• May contain abstract methods that must be implemented by subclasses

• Can have both abstract and non-abstract methods

• Used to define a common interface for subclasses

To count the number of links on a web page, you can use a web scraping tool or inspect the page's HTML code.

• Use a web scraping tool like BeautifulSoup or Selenium to extract all the links from the webpage.

• Inspect the HTML code of the webpage and look for anchor tags (<a>) which contain the links.

• Count the number of anchor tags to determine the total number of links on the webpage.

Use CSS selector to locate element on webpage

• Use unique id or class names to locate element

• Use CSS selectors like 'id', 'class', 'name', 'tag name', etc.

• Use XPath if necessary for complex element locating

The sum of principal diagonal elements of a matrix is calculated by adding the elements from the top left to bottom right.

• Add the elements from the top left to bottom right of the matrix to get the sum of principal diagonal elements.

• For example, in a 3x3 matrix [[1, 2, 3], [4, 5, 6], [7, 8, 9]], the principal diagonal elements are 1, 5, and 9. Their sum would be 15.

Resolved a critical data synchronization issue in a distributed system, enhancing performance and reliability.

• Identified a race condition causing data inconsistencies during peak loads.

• Implemented a locking mechanism to ensure data integrity across nodes.

• Conducted extensive testing to validate the solution under various scenarios.

• Collaborated with cross-functional teams to align on system architecture changes.

Find the largest string in a given array of strings

• Iterate through the array and compare the length of each string to find the largest one

• Use a variable to keep track of the largest string found so far

• Return the largest string at the end

The most used technologies during work include Java, Spring Boot, AWS, Docker, and Kubernetes.

• Java

• Spring Boot

• AWS

• Docker

• Kubernetes

OOPs (Object-Oriented Programming) is a programming paradigm based on the concept of objects, which can contain data and code.

• OOPs focuses on creating objects that interact with each other to solve complex problems

• Key principles include encapsulation, inheritance, polymorphism, and abstraction

• Encapsulation allows data hiding and bundling of data with methods that operate on that data

• Inheritance enables a new class to inherit properties and behavior of an existing class

• Polymor...read more

Lock and Synchronised are both mechanisms used for thread synchronization in Java.

• Lock is a more flexible and powerful mechanism compared to synchronized keyword in Java.

• Lock interface provides more functionalities like tryLock(), lockInterruptibly(), etc.

• Lock allows for more fine-grained control over locking and unlocking of resources.

• Synchronized keyword is simpler to use but may lead to deadlocks in complex scenarios.

• Synchronized keyword is implicitly used in synchronized ...read more

Remove zeros from arrays list of strings

• Iterate through each string in the array

• Use filter method to remove zeros from each string

• Return the updated array without zeros

FindElements method returns a list of web elements matching the specified locator.

• Return type of FindElements is List

• It returns a list of all elements matching the specified locator

• Example: List elements = driver.findElements(By.xpath("//input[@type='text']"));