20+ Larsen & Toubro Limited Interview Questions and Answers

Instance of keyword is used to compare an object to a specified class type.

• Instance of keyword returns true if the object is an instance of the specified class.

• It can be used to check if an object is of a specific class type before casting.

• Example: if(obj instanceof String) { // do something }

Use SQL INSERT INTO SELECT statement to copy data from 2 tables and paste into a 3rd table.

• Use INSERT INTO SELECT statement to copy data from 2 tables and paste into a 3rd table.

• Specify the columns you want to copy from each table in the SELECT statement.

• Make sure the columns in the SELECT statement match the columns in the 3rd table where you are pasting the data.

Exceptions are unexpected events that disrupt the normal flow of a program. Exception handling is the process of dealing with these events.

• Exceptions are objects that represent an abnormal condition or error in a program.

• Exception handling allows developers to gracefully handle errors and prevent the program from crashing.

• Java provides try-catch blocks for handling exceptions. The try block contains the code that may throw an exception, and the catch block handles the excepti...read more

SQL joins are used to combine data from two or more tables based on a related column.

• Joins are used to retrieve data from multiple tables in a single query.

• Common types of joins are inner join, left join, right join, and full outer join.

• Joining tables can be done using the JOIN keyword and specifying the columns to join on.

• Example: SELECT * FROM table1 JOIN table2 ON table1.column = table2.column;

• Joins can be used to combine data from different tables such as customer and ord...read more

The algorithm used in the project is LSTM.

• LSTM stands for Long Short-Term Memory and is a type of recurrent neural network.

• It is commonly used for sequential data analysis such as time series forecasting, speech recognition, and natural language processing.

• LSTM networks have the ability to remember long-term dependencies and avoid the vanishing gradient problem.

• They consist of memory cells, input gates, output gates, and forget gates.

• Example applications of LSTM include predi...read more

Oops concepts in Java are fundamental concepts of object-oriented programming like inheritance, polymorphism, encapsulation, and abstraction.

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

• Polymorphism: Allows objects to be treated as instances of their parent class.

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

• Abstraction: Hiding the implementation details and showing only the necessary features of an o...read more

Reverse a string using any programming language

• Use built-in functions like reverse() or slice() in languages like Python or JavaScript

• Iterate through the string in reverse order and append each character to a new string

• Use a stack data structure to push each character onto the stack and then pop them off to reverse the string

A palindrome is a word, phrase, number, or other sequence of characters that reads the same forward and backward.

• Create a function to check if a given string is a palindrome.

• Remove all non-alphanumeric characters and convert the string to lowercase before checking.

• Compare characters from both ends of the string to determine if it is a palindrome.

Interface in Java is a reference type, similar to a class, that can contain only constants, method signatures, default methods, static methods, and nested types.

• Interfaces are used to define a contract for classes that implement them.

• Classes can implement multiple interfaces in Java.

• Interfaces cannot have instance fields, constructors, or non-static methods.

• Example: interface Shape { void draw(); }

• Example: class Circle implements Shape { public void draw() { // draw circle } ...read more

Abstraction is a concept in object-oriented programming where only relevant data is shown to the user while hiding unnecessary details.

• Abstraction helps in simplifying complex systems by only showing essential features.

• It allows for creating abstract classes and interfaces in Java.

• Example: In a car, the driver only needs to know how to drive it without understanding the internal workings of the engine.

Data refers to facts, statistics, or information collected for analysis or reference.

• Data is raw, unprocessed information.

• It can be in the form of numbers, text, images, or any other format.

• Examples include customer names, product prices, and sales figures.

• Data can be structured (organized in a specific way) or unstructured (not organized).

Arrays are a collection of elements of the same data type, while Strings are a sequence of characters.

• Arrays can store multiple values of the same data type, accessed by index.

• Strings are immutable sequences of characters, can be manipulated using various methods.

• Example: int[] numbers = {1, 2, 3}; String name = "John";

Preprocessed data is data that has been cleaned, transformed, and organized for analysis or modeling.

• Preprocessed data is often used in machine learning and data analysis to improve the accuracy and efficiency of models.

• Common preprocessing steps include removing missing values, scaling features, and encoding categorical variables.

• Examples of preprocessing techniques include normalization, standardization, one-hot encoding, and feature scaling.

LSTM is a type of recurrent neural network that can handle long-term dependencies.

• LSTM stands for Long Short-Term Memory.

• It uses gates to control the flow of information.

• It can remember information for a longer period of time compared to traditional RNNs.

• It is commonly used in natural language processing and speech recognition tasks.

• LSTM has been shown to be effective in predicting stock prices and weather patterns.

Spring Boot is a framework for building Java-based enterprise applications quickly and with minimal configuration.

• Spring Boot simplifies the process of creating stand-alone, production-grade Spring-based applications.

• It provides a range of features including embedded servers, auto-configuration, and production-ready metrics.

• Spring Boot allows developers to focus on writing business logic rather than configuring the application.

• It is widely used in the development of microserv...read more

Test the strength of password validation by checking for various criteria

• Check for minimum length requirement

• Include uppercase and lowercase letters

• Include numbers and special characters

• Test against common passwords or dictionary words

• Ensure password expiration and lockout policies are enforced

OWASP Top 10 is a list of the most critical web application security risks.

• It is updated every 3-4 years by the Open Web Application Security Project (OWASP)

• The list includes vulnerabilities such as injection, broken authentication and session management, cross-site scripting (XSS), and more

• It is used as a guide for developers and security professionals to prioritize their security efforts

• The latest version is OWASP Top 10 2017

ML algorithms are mathematical models used to identify patterns and make predictions from data.

• ML algorithms can be supervised, unsupervised, or semi-supervised

• Supervised algorithms include linear regression, decision trees, and neural networks

• Unsupervised algorithms include k-means clustering and principal component analysis

• Semi-supervised algorithms combine elements of both supervised and unsupervised learning

• ML algorithms require training data to learn from and testing dat...read more

Spring IOC (Inversion of Control) is a design pattern where the control of object creation and lifecycle is shifted from the application code to the Spring framework.

• In Spring IOC, objects are created and managed by the Spring container.

• It helps in achieving loose coupling between classes by removing the dependency on object creation.

• Dependency Injection is a key concept in Spring IOC, where the dependencies of a class are injected at runtime.

• Example: Instead of creating obje...read more

Angular is a popular open-source front-end web application framework developed by Google.

• Angular is used for building dynamic web applications.

• It allows for the creation of single-page applications.

• Angular uses TypeScript for building applications.

• It provides features like data binding, dependency injection, and routing.

• Angular has a large community and ecosystem with many libraries and tools available.

Abstraction in Java is a concept where we hide the implementation details and only show the necessary features of an object.

• Abstraction allows us to focus on what an object does rather than how it does it.

• In Java, abstraction is achieved through abstract classes and interfaces.

• Abstract classes cannot be instantiated and can have abstract methods that must be implemented by subclasses.

• Interfaces in Java are like abstract classes but can only contain abstract methods and consta...read more

Interface in Java is a reference type in Java, similar to a class, that can contain only constants, method signatures, default methods, static methods, and nested types.

• Interfaces are used to achieve abstraction and multiple inheritance in Java.

• All methods in an interface are public and abstract by default.

• A class can implement multiple interfaces but can only extend one class.

• Example: interface MyInterface { void myMethod(); }

• Example: class MyClass implements MyInterface { p...read more

Joins are used to combine rows from two or more tables based on a related column. DDL, DML, and TCL are SQL commands for data manipulation and transaction control.

• Joins are used in SQL to retrieve data from multiple tables based on a related column.

• DDL (Data Definition Language) commands are used to define the structure of database objects like tables, indexes, etc.

• DML (Data Manipulation Language) commands are used to manipulate data in the database, such as INSERT, UPDATE, D...read more

Different types of tests include unit testing, integration testing, system testing, and acceptance testing.

• Unit testing focuses on testing individual components or functions in isolation.

• Integration testing verifies that different components work together correctly.

• System testing tests the entire system as a whole.

• Acceptance testing ensures that the system meets the requirements and is ready for deployment.

Stream API in Java provides a way to process collections of objects in a functional style.

• Stream API allows for easy manipulation of collections using functional programming concepts like map, filter, and reduce.

• It supports lazy evaluation, allowing for efficient processing of large datasets.

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

Designed a microservices architecture using Docker and Kubernetes for a real-time analytics platform

• Utilized Docker containers to encapsulate each microservice

• Implemented Kubernetes for container orchestration and scaling

• Used Kafka for real-time data streaming between microservices

Current CTC is $80,000 and expecting $90,000 to join.

• Current CTC: $80,000

• Expected CTC to join: $90,000

Observables and promises are both used for handling asynchronous operations in JavaScript.

• Observables are used for handling multiple values over time, while promises are used for handling a single value at a time.

• Observables can be cancelled, while promises cannot be cancelled.

• Promises have a built-in mechanism for error handling using the catch method, while observables use the error callback function.

• Observables are part of the RxJS library, while promises are built-in to J...read more