50+ TCS Interview Questions and Answers

Array list stores elements in contiguous memory locations, while linked list stores elements in nodes with pointers to the next node.

• Array list allows fast access to elements using index, while linked list allows for fast insertion and deletion of elements.

• Array list is ideal for scenarios where random access is required, while linked list is suitable for scenarios where frequent insertion and deletion operations are needed.

• Example: Array list is used in scenarios where eleme...read more

Answering questions related to software development and Salesforce administration.

• Process Builder is a visual tool in Salesforce used to automate business processes.

• Types of relationships in Salesforce include lookup, master-detail, and many-to-many relationships.

• User represents an individual who can log in and access Salesforce, Profile defines the permissions and settings for a user, and Role determines the hierarchy and access levels within an organization.

• Workflow in Sale...read more

Code to find pairs in array list with sum 8

• Iterate through array and check if pair sum is 8

• Use a hashmap to store elements and their complements

• Time complexity O(n)

To communicate two APIs in Spring Boot, you can use RestTemplate or WebClient to make HTTP requests.

• Use RestTemplate to make synchronous HTTP requests between APIs

• Use WebClient to make asynchronous HTTP requests between APIs

• Implement error handling and exception handling for robust communication

• Consider using Feign client for declarative REST client

• Ensure proper authentication and authorization mechanisms are in place

RestController and Controller annotations are used in Spring framework to define classes as controllers for handling HTTP requests.

• RestController annotation is used to define a class as a RESTful web service controller, which returns data in JSON or XML format.

• Controller annotation is used to define a class as a traditional Spring MVC controller, which returns a view to the client.

• Both annotations are used to handle HTTP requests and map them to specific methods in the contro...read more

The @Data annotation is used in Java to declare a class as a data class, while the @Value annotation is used in Spring to create immutable objects.

• The @Data annotation in Java is used to generate getters, setters, toString, equals, and hashCode methods for a class.

• The @Value annotation in Spring is used to create immutable objects with final fields that are initialized through constructor injection.

• Both annotations help in reducing boilerplate code and improving code readabil...read more

To read values from application properties file, use a properties file reader in the programming language being used.

• Use a properties file reader class in the programming language being used (e.g. Properties class in Java).

• Load the properties file using the reader class.

• Access the values using keys specified in the properties file.

Annotations used in Spring framework for dependency injection

• Used in Spring framework to inject dependencies

• Qualifier is used to specify which bean to autowire when multiple beans of the same type exist

• Autowired is used to automatically inject the dependency

Code to print even numbers and their squares in Java8

• Use Java8 Stream API to generate even numbers

• Map each even number to its square using map() function

• Print the even numbers and their squares using forEach() function

To make a specific what? Please provide more context.

• Please provide more information about what needs to be made specific

• Clarify the scope and purpose of the specific thing

• Consider using clear and concise language to define the specific thing

Annotation used in Spring framework to indicate that a class declares one or more @Bean methods

• Used in Spring framework to define configuration classes

• Indicates that a class should be considered as a source of bean definitions

• Helps Spring to understand the configuration and create beans accordingly

Intermediate operations in Java 8 are used to process the stream elements and produce a new stream as output.

• Intermediate operations are lazy and do not start processing the stream until a terminal operation is invoked.

• Examples of intermediate operations include filter, map, sorted, distinct, limit, and skip.

• Intermediate operations can be chained together to form a pipeline of operations on a stream.

Using MultivaluedMap to add a list of values to a particular key in Java

• Create a MultivaluedMap object from Apache Commons Collections library

• Use the put method to add a key-value pair where the value is a list of values

• Use the get method to retrieve the list of values for a particular key

Multi threading is the ability of a program to perform multiple tasks concurrently.

• It allows for better utilization of CPU resources

• It can improve program performance and responsiveness

• Examples include web servers handling multiple requests simultaneously

• It requires careful management of shared resources to avoid race conditions

Method reference is a shorthand syntax for lambda expressions to call a method.

• Method reference can be used to refer to static methods, instance methods, and constructors.

• It helps in improving code readability and conciseness.

• Example: list.forEach(System.out::println) is equivalent to list.forEach(item -> System.out.println(item)).

Static class is used to create classes that cannot be instantiated and can only have static members.

• Static class cannot be instantiated, meaning you cannot create an object of a static class.

• Static class can only have static members such as static fields, methods, properties, and events.

• Static classes are commonly used for utility classes where all members are static and do not require an instance to be accessed.

Yes, we can create multiple objects in programming.

• Objects are instances of a class.

• We can create multiple objects of the same class.

• Each object has its own set of instance variables and methods.

• Objects can interact with each other through their methods.

• Example: creating multiple instances of a 'Person' class for different people.

Encapsulation types are data, procedural and combination.

• Data encapsulation hides data from outside world and provides access through methods.

• Procedural encapsulation hides implementation details of a procedure.

• Combination encapsulation is a mix of data and procedural encapsulation.

• Examples include private variables in a class, access modifiers in Java, etc.

Java is a popular object-oriented programming language used for developing various applications.

• Java was developed by Sun Microsystems in 1995.

• It is platform-independent and can run on any operating system.

• Java is used for developing web applications, mobile applications, desktop applications, and games.

• It is known for its security features and is widely used in enterprise applications.

• Java has a vast library of pre-built classes and APIs that make development faster and easi...read more

Sample code using @functional annotation

• Use @FunctionalInterface annotation to declare a functional interface in Java

• Functional interfaces have exactly one abstract method

• Example: @FunctionalInterface interface MyFunctionalInterface { void myMethod(); }

I have configured various software systems and tools for development purposes.

• Configured IDEs such as Eclipse and Visual Studio for development

• Set up version control systems like Git and SVN

• Installed and configured build tools like Maven and Gradle

• Configured application servers like Tomcat and JBoss

• Set up databases like MySQL and Oracle for development and testing

Abstraction is the process of hiding complex implementation details and providing a simplified interface.

• Abstraction allows us to focus on the essential features of an object or system while ignoring the irrelevant details.

• An abstract class is a class that cannot be instantiated and is meant to be subclassed.

• Abstract classes can have both abstract and non-abstract methods.

• Abstract classes are used to define common behavior and characteristics that can be inherited by subclass...read more

Java 8 introduced several new features including lambda expressions, functional interfaces, streams, and the new date and time API.

• Lambda expressions allow you to write code in a more concise and readable way.

• Functional interfaces provide a way to define interfaces with a single abstract method.

• Streams allow for processing sequences of elements in a functional style.

• The new date and time API provides improved date and time handling capabilities.

Restcontroller is used for RESTful web services while controller is used for traditional web applications.

• RestController is a specialized version of @Controller

• RestController returns data in JSON or XML format

• Controller returns a view to be rendered by the browser

• RestController is used for building RESTful web services

• Controller is used for traditional web applications

• Example: @RestController vs @Controller in Spring MVC

Static variables in C are variables that retain their value between function calls.

• Static variables are initialized only once, at the start of the program execution.

• They retain their value throughout the program's execution.

• Static variables are stored in the data segment of the program's memory.

• They have a default value of 0 if not explicitly initialized.

Streams in Java 8 are sequences of elements that support functional-style operations.

• Streams allow for processing sequences of elements in a functional way

• They can be created from collections, arrays, or I/O resources

• Common operations on streams include map, filter, reduce, and collect

Shallow copy in JavaScript creates a new object and copies the references of the original object's properties.

• Shallow copy only copies the top-level properties of an object, not nested objects.

• Changes to the nested objects in the copied object will affect the original object.

• Shallow copy can be done using Object.assign() or spread operator.

Static variables are used to store values that are shared among all instances of a class or function.

• Static variables retain their value between function calls

• They are initialized only once at the start of the program

• Useful for maintaining state across multiple function calls

Immutable class is a class whose instances cannot be modified after creation.

• Immutable class instances have all fields as final and private.

• Immutable classes have no setter methods, only getter methods.

• Examples of immutable classes in Java are String, Integer, and LocalDate.

Parallel stream is a feature in Java that allows processing elements of a stream concurrently.

• Parallel stream can be created from a regular stream using parallel() method.

• It utilizes multiple threads to process elements in parallel, improving performance for large datasets.

• However, parallel stream may not always be faster than sequential stream due to overhead of managing multiple threads.

• Example: List list = Arrays.asList("apple", "banana", "cherry"); list.parallelStream().f...read more

An object is an instance of a class that encapsulates data and behavior.

• Objects have attributes (data) and methods (behavior).

• Objects can interact with each other through method calls.

• Objects can be created from classes.

• Examples of objects include a car, a person, or a bank account.

Map applies a function to each element in a collection and returns a new collection. FlatMap applies a function that returns a collection for each element and flattens the result into a single collection.

• Map transforms each element of a collection using a function and returns a new collection of the same size.

• FlatMap transforms each element of a collection using a function that returns a collection, then flattens the result into a single collection.

• Example: map([1, 2, 3], x =...read more

Java 8 Stream is a sequence of elements that can be processed in parallel or sequentially.

• Stream is not a data structure, it does not store elements

• Stream operations are divided into intermediate and terminal operations

• Intermediate operations return a new stream and terminal operations return a result

• Example: stream.filter(x -> x > 5).map(x -> x * 2).forEach(System.out::println)

• Example: stream.reduce(0, (a, b) -> a + b)

In C, 'volatile' keyword is used to indicate that a variable may be changed unexpectedly by external factors.

• Prevents compiler optimizations that assume the variable's value will not change

• Useful for variables accessed by multiple threads or hardware devices

• Example: volatile int x; // 'x' may be changed by hardware interrupts

Singleton is a design pattern that restricts the instantiation of a class to one object.

• Ensures a class has only one instance and provides a global point of access to it

• Commonly used in scenarios where only a single instance of a class is needed, such as database connections or configuration settings

• Implemented by creating a static method that returns the same instance of the class every time it is called

Object-oriented programming (OOP) is a programming paradigm based on the concept of objects.

• OOP is a programming approach that focuses on creating objects that contain both data and methods.

• The main pillars of OOP are encapsulation, inheritance, and polymorphism.

• Encapsulation allows objects to hide their internal state and expose only necessary information.

• Inheritance enables the creation of new classes based on existing classes, inheriting their properties and behaviors.

• Poly...read more

Static vs Singleton: Static refers to a class member that belongs to the class itself, while Singleton is a design pattern that restricts the instantiation of a class to a single object.

• Static members are shared among all instances of a class, while Singleton ensures only one instance of a class exists.

• Static members can be accessed without creating an object, while Singleton requires instantiation.

• Static members are typically used for utility methods or constants, while Sing...read more

A collection is a group of related objects or data items that are stored together.

• Collections can be used to store and manipulate multiple items of the same type.

• Examples of collections include arrays, lists, sets, and maps.

• Collections provide methods for adding, removing, and accessing items in the group.

Use SQL query with subquery to find 3rd highest salary in a table.

• Use ORDER BY and LIMIT to get the 3rd highest salary.

• Use a subquery to exclude the top 2 highest salaries before selecting the 3rd highest.

Union combines and removes duplicates, Union All combines all rows including duplicates.

• Union removes duplicates, Union All includes duplicates

• Union is slower than Union All as it has to remove duplicates

• Union requires the same number of columns in both queries, Union All does not

Hibernate is an ORM framework for Java, Kafka is a distributed event streaming platform, and GCP is Google Cloud Platform.

• Hibernate is an ORM (Object-Relational Mapping) framework that simplifies database interactions in Java applications.

• Kafka is a distributed event streaming platform used for building real-time data pipelines and streaming applications.

• GCP (Google Cloud Platform) is a suite of cloud computing services offered by Google for storage, computing, and data analy...read more

Dependency Injection is a design pattern where components are given their dependencies rather than creating them internally.

• Allows for better code reusability and testability

• Promotes loose coupling between components

• Commonly used in frameworks like Spring for Java

• Example: Instead of a class creating an instance of another class it needs, the instance is provided externally

Garbage collector is a program that automatically manages memory by reclaiming unused memory.

• Automatically frees up memory that is no longer in use

• Prevents memory leaks by reclaiming unused memory

• Examples include Java's garbage collector and C#'s garbage collector

HashMap is a data structure that stores key-value pairs and allows for fast retrieval of values based on keys.

• HashMap is part of the Java Collections framework.

• It uses hashing to store elements in key-value pairs.

• It allows for quick retrieval of values based on keys.

• Example: HashMap map = new HashMap<>();

Yes, I have a strong foundation in computer skills including programming languages, databases, and software development tools.

• Proficient in programming languages such as Java, Python, and C++

• Experience with databases like MySQL and MongoDB

• Familiarity with software development tools like Git and Jira

Expectation is a belief about what will happen in the future or what should happen in a particular situation.

• Expectation is a mental state anticipating a certain outcome.

• It can be based on past experiences, assumptions, or desires.

• Expectations can influence behavior and emotions.

• Unmet expectations can lead to disappointment or frustration.

• Examples: Expecting a promotion after working hard, expecting a package to arrive on time.

OOPS concepts in Java refer to Object-Oriented Programming principles like Inheritance, Encapsulation, Polymorphism, and Abstraction.

• Inheritance: Allows a class to inherit properties and behavior from another class.

• Encapsulation: Bundling data and methods that operate on the data into a single unit.

• Polymorphism: Ability to present the same interface for different data types.

• Abstraction: Hiding the implementation details and showing only the necessary features of an object.

JSX is a syntax extension for JavaScript used in React to write HTML elements in JavaScript code.

• JSX allows developers to write HTML-like code in JavaScript files

• It makes the code more readable and easier to understand

• JSX elements are transpiled into regular JavaScript by tools like Babel

Volatile keyword in programming is used to indicate that a variable's value can be changed unexpectedly.

• Volatile keyword is used in multithreaded programming to ensure that the variable's value is always read from memory and not cached.

• It is commonly used when working with hardware registers or shared variables in concurrent programming.

• Example: volatile int x = 10; // variable x is marked as volatile to prevent compiler optimizations

Set is an unordered collection of unique elements, while ordered set is a collection of unique elements with a defined order.

• Set does not maintain any specific order of elements, while ordered set maintains the order of elements based on insertion.

• In a set, elements are stored in a random order, while in an ordered set, elements are stored in the order they were inserted.

• Examples of sets include {1, 2, 3} while examples of ordered sets include {3, 1, 2}.

I am looking for new challenges and opportunities for growth.

• Seeking new challenges to expand my skills and knowledge

• Interested in working on different projects and technologies

• Hoping to advance my career and take on more responsibilities