500+ Lead Engineer Interview Questions and Answers

Finding repeating number with linear complexity.

• Use Floyd's cycle-finding algorithm to detect the cycle in the sequence.

• Maintain two pointers, one moving at a rate of one step and the other at a rate of two steps.

• When they meet, move one pointer to the start and keep the other pointer at the meeting point.

• Move both pointers at a rate of one step until they meet again, which is the start of the cycle.

• The number at the start of the cycle is the repeating number.

Converting a core PHP project into a framework involves several steps to organize and optimize the codebase.

• Choose a suitable framework like Laravel, Symfony, or CodeIgniter.

• Identify and separate the business logic from presentation logic.

• Migrate existing PHP files into the framework's directory structure.

• Refactor code to utilize framework features like routing, ORM, and templating.

• Update database connections to use the framework's ORM or query builder.

• Integrate existing func...read more

Our automation framework is built using Selenium WebDriver and TestNG.

• We use Selenium WebDriver for browser automation

• TestNG is used for test management and reporting

• We also use Apache POI for data-driven testing

• Our framework is designed to be modular and scalable

• We have implemented page object model design pattern

• We use Jenkins for continuous integration and deployment

Unit test cases for a module can be created by identifying different scenarios and inputs to test the functionality.

• Identify the different functionalities of the module that need to be tested

• Create test cases for each functionality, including positive and negative scenarios

• Ensure test cases cover edge cases and boundary conditions

• Use testing frameworks like JUnit, NUnit, or pytest to automate the testing process

• Mock dependencies or use stubs to isolate the module being tested

Nexus 9K hardware models used in Leaf and spine architecture.

• Nexus 9372PX and 9372TX used as leaf switches

• Nexus 9504, 9508, and 9516 used as spine switches

• Nexus 93108TC-EX and 93180YC-EX also used as leaf switches

• All models support VXLAN and ACI

• Highly scalable and flexible architecture

I have worked on developing custom components, templates, workflows, and integrating third-party systems in AEM. In Java, I have worked on backend development, RESTful services, and database interactions.

• Developed custom components and templates in AEM

• Implemented workflows for content approval processes

• Integrated third-party systems with AEM

• Backend development in Java

• Created RESTful services

• Worked on database interactions

A circuit breaker is an electrical switch that automatically interrupts an electrical circuit when the current exceeds a certain limit.

• Circuit breakers are designed to protect electrical circuits from damage caused by overloading or short circuits.

• They work by detecting an increase in current flow and then tripping to interrupt the circuit.

• Circuit breakers can be reset manually or automatically depending on the type.

• They come in different sizes and ratings depending on the am...read more

Transport protocol in CAN J1939 is used for transmitting large data packets over the network.

• Transport protocol breaks down large data packets into smaller segments for transmission.

• It uses a flow control mechanism to ensure all segments are received and reassembled in the correct order.

• Examples of transport protocols in J1939 include BAM (Broadcast Announce Message) and RTS/CTS (Request To Send/Clear To Send).

Outages for line/switchyard are managed by the load dispatch centre through coordination and communication.

• Outages are scheduled in advance to minimize impact on the grid and consumers.

• Load dispatch centre coordinates with the concerned authorities to plan and execute the outage.

• Alternative arrangements are made to ensure continuity of power supply during the outage.

• Regular updates are provided to stakeholders regarding the status of the outage and expected restoration time.

Debugging a project in production requires a systematic approach to identify and fix errors efficiently.

• Start by identifying the specific error message or symptom reported by users or monitoring tools.

• Review recent code changes or deployments that may have introduced the error.

• Use logging and monitoring tools to gather more information about the error and its impact.

• Replicate the issue in a controlled environment if possible to understand the root cause.

• Apply fixes carefully ...read more

The question is unclear. Please provide more context.

Media query for 3 divs in row for desktop and column for mobile view

• Use min-width and max-width to target desktop and mobile views respectively

• Set display property to flex and flex-wrap to wrap for desktop view

• Set display property to block for mobile view

A thread-safe implementation of the Singleton pattern ensures that only one instance of a class is created in a multi-threaded environment.

• Use double-checked locking to minimize the use of synchronization and improve performance.

• Declare the instance variable as volatile to ensure visibility across threads.

• Use synchronized block to create the instance if it doesn't exist.

• Return the instance variable in the getInstance() method.

Yes, I have knowledge on PLM tools.

• I have experience working with PLM tools such as Teamcenter and Windchill.

• I have used PLM tools to manage product data, collaborate with cross-functional teams, and track project progress.

• I am familiar with PLM concepts such as BOM management, change management, and version control.

• I have also worked on customizing PLM tools to meet specific business requirements.

• Overall, my experience with PLM tools has helped me streamline product developm...read more

No, DML operations cannot be performed on UDF functions.

• UDF functions are read-only and cannot modify the data in the database.

• DML operations can only be performed on tables or views.

• UDF functions can be used in SELECT statements to retrieve data.

• Examples of UDF functions include string manipulation, date calculations, and mathematical operations.

PHP is a server-side scripting language used for web development. The current version is PHP 8.0.

• PHP stands for Hypertext Preprocessor

• It is an open-source language

• PHP is used for creating dynamic web pages

• PHP 8.0 was released on November 26, 2020

Design control process ensures products meet requirements. PLM tools manage product data.

• Design control process ensures products meet design requirements and regulatory standards

• PLM tools (Product Lifecycle Management) are used to manage product data, documents, and processes

• Examples of PLM tools include Teamcenter, Windchill, and Agile PLM

Printing to console will not happen as System.out is null.

• System.out is a static field in the System class that represents the standard output stream.

• Assigning null to System.out means that any attempt to print to console will result in a NullPointerException.

• To redirect console output to a file or another output stream, System.setOut() method can be used.

The Java Virtual Machine (JVM) is an abstract computing machine that enables a computer to run Java programs.

• JVM is platform-independent and converts Java bytecode into machine code.

• It consists of class loader, runtime data areas, execution engine, and native method interface.

• JVM memory is divided into method area, heap, stack, and PC register.

• Examples of JVM implementations include Oracle HotSpot, OpenJ9, and GraalVM.

Business rules are guidelines or constraints defined by a business, while JavaScript is a programming language used for web development.

• Business rules are specific to a business domain and define constraints or guidelines for operations.

• JavaScript is a programming language used for creating interactive web pages and web applications.

• Business rules are typically defined by business analysts or stakeholders, while JavaScript is written by developers.

• Use business rules to enforc...read more

Convert even numbers in a list of strings to odd by adding 1

• Iterate through the list of strings and check if each element is a number

• If the number is even, convert it to odd by adding 1

• Return the modified list of strings

To find out 1m3 concrete costing, calculate the cost of materials and labor involved.

• Determine the cost of cement, sand, aggregate, and water per cubic meter

• Calculate the labor cost involved in mixing, pouring, and finishing the concrete

• Add the material and labor costs to get the total cost of 1m3 concrete

• Consider any additional costs such as transportation, equipment rental, and taxes

Performance testing challenges include identifying bottlenecks, simulating real-world scenarios, and analyzing results.

• Identifying bottlenecks in the system

• Simulating real-world scenarios to accurately test performance

• Analyzing results to identify areas for improvement

• Ensuring test environment is representative of production environment

• Managing test data and test scripts

• Dealing with network latency and other external factors

• Ensuring tests are repeatable and consistent

• Balancin...read more

There will be 19 matches in total in a knock out tournament with 20 teams.

• In a knock out tournament, each match eliminates one team.

• To determine the number of matches, subtract 1 from the total number of teams.

• For 20 teams, there will be 20 - 1 = 19 matches.

I have worked on Linux kernel versions 3.x, 4.x, and 5.x.

• Worked on Linux kernel versions 3.x, 4.x, and 5.x

• Experience with kernel development and debugging

• Familiar with kernel modules and drivers

Complex algorithms in DSA optimize data processing and enhance performance across various applications.

• 1. Dijkstra's Algorithm: Used for finding the shortest path in graphs, e.g., GPS navigation.

• 2. A* Search Algorithm: Combines heuristics with Dijkstra's for pathfinding in games.

• 3. Dynamic Programming: Solves problems like the Knapsack problem and Fibonacci sequence efficiently.

• 4. QuickSort: A divide-and-conquer algorithm for efficient sorting, average time complexity O(n log...read more

SQL query to select all columns from two tables.

• Use SELECT statement to select columns from tables.

• Use aliases to differentiate columns from different tables.

• Separate table names with comma in FROM clause.