400+ Lead Engineer Interview Questions and Answers

A heap dump is a snapshot of the memory usage of a Java application at a specific point in time.

• Heap dumps can be generated using tools like jmap or VisualVM.

• They provide detailed information about objects in memory, their sizes, and references.

• Analyzing a heap dump can help identify memory leaks by pinpointing objects that are consuming excessive memory.

• Common signs of memory leaks in a heap dump include a large number of objects of the same type or objects that should have ...read more

The default connection pooling in Spring Boot is HikariCP, which can be customized through properties in the application.properties file.

• HikariCP is the default connection pooling library in Spring Boot, known for its high performance and low overhead.

• To customize the connection pooling, you can modify properties like 'spring.datasource.hikari.*' in the application.properties file.

• For example, you can set maximum pool size, connection timeout, idle timeout, and other paramete...read more

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

Integrating third party libraries involves adding the library to the project dependencies and configuring it for use.

• Add the library as a dependency in the project's build file (e.g. Gradle, Maven)

• Import the necessary classes or functions from the library in your code

• Configure any necessary settings or initialization code for the library to work properly

• Ensure compatibility with the project's existing codebase and dependencies

• Update the project's documentation to include info...read more

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

During emergency shutdown, the execution plan involves immediate identification of the problem and taking necessary steps to mitigate it.

• Identify the cause of the emergency shutdown

• Initiate the emergency shutdown procedure

• Isolate the affected equipment or area

• Notify relevant personnel and authorities

• Implement emergency response plan

• Conduct post-shutdown analysis and investigation

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

The company has achieved several milestones in the last 3 years.

• Launched a new product line that increased revenue by 25%

• Expanded into three new international markets

• Received a patent for a new technology

• Implemented a new quality control system that reduced defects by 30%

• Won an industry award for innovation

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 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

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

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

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.

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

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

Defects in BOPP film can include wrinkles, bubbles, and scratches. Resolving them requires understanding material properties and processing conditions.

• Identify the specific defect in the BOPP film, such as wrinkles, bubbles, or scratches.

• Analyze the root cause of the defect, which could be related to material properties or processing conditions.

• Adjust processing parameters like temperature, speed, or tension to minimize defects.

• Ensure proper handling and storage of BOPP film ...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.

The question is unclear. Please provide more context.

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).

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.

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.

Accelerated ageing process in storage chamber of suture testing lab is a method to simulate long-term storage conditions in a shorter period of time.

• Accelerated ageing involves subjecting the sutures to elevated temperatures and humidity levels to speed up degradation processes.

• This process helps researchers predict the shelf life and performance of sutures under normal storage conditions.

• Common accelerated ageing methods include thermal cycling, UV exposure, and chemical exp...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.

Active agents initiate actions while passive agents respond to actions.

• Active agents are proactive while passive agents are reactive.

• Active agents initiate change while passive agents undergo change.

• Examples of active agents include enzymes, hormones, and neurotransmitters while examples of passive agents include water, air, and salt.

• Active agents are often associated with living organisms while passive agents are associated with non-living things.

Ultrasonic level transmitter uses sound waves to measure the level of liquid or solid in a container.

• The transmitter sends high-frequency sound waves towards the surface of the liquid or solid.

• The waves bounce back and are received by the transmitter.

• The time taken for the waves to return is measured and used to calculate the distance to the surface.

• The distance is then converted into a level measurement and transmitted to a control system.

• Ultrasonic level transmitters are co...read more

Linux system process, PKI, Cryptography, and Secure Boot process are all important components of secure computing.

• Linux system process refers to the way in which the operating system manages and executes programs and applications.

• PKI (Public Key Infrastructure) is a system for managing digital certificates and public-private key pairs to ensure secure communication.

• Cryptography involves the use of mathematical algorithms to secure data and communications.

• Secure Boot process i...read more

To design a tool like Google Looker, I would start by understanding the user's needs and requirements.

• Conduct user research to understand their needs and pain points

• Identify key features and functionalities required

• Create wireframes and prototypes to test and refine the design

• Collaborate with cross-functional teams to ensure seamless integration with existing systems

• Continuously gather feedback and iterate on the design

• Ensure scalability and security of the tool

Ambassador pattern is a Kubernetes design pattern that allows for external access to services.

• It involves using a sidecar container to proxy requests from outside the cluster to the service.

• The sidecar container can handle tasks such as authentication and load balancing.

• It allows for decoupling of the service from the external access mechanism.

• Examples include the use of Ambassador and Istio as implementations of the pattern.

A cursor is a database object used to manipulate data in a result set.

• A cursor is used to traverse through a result set one row at a time.

• It can be used to update or delete rows in a result set.

• Attributes of a cursor include its name, type, scrollability, and sensitivity.

• Examples of cursor types include forward-only, static, dynamic, and keyset-driven.

1. Different types of welds and their applications. 2. Stress, strain, torque, buoyancy, etc.

• Different types of welds include butt welds, fillet welds, lap welds, etc.

• Butt welds are used to join two pieces of metal together end-to-end, while fillet welds are used to join two pieces of metal together at right angles.

• Lap welds are used to join two pieces of metal together that overlap each other.

• Stress is the force per unit area that a material is subjected to, while strain is ...read more

Read DTCs service in UDS is used to retrieve diagnostic trouble codes from a vehicle's electronic control unit.

• DTCs are codes that indicate a problem with a vehicle's systems or components

• The read DTCs service allows technicians to identify and diagnose issues with a vehicle

• The service is part of the Unified Diagnostic Services (UDS) protocol used in automotive diagnostics

• Examples of DTCs include P0300 (random/multiple cylinder misfire detected) and U0100 (lost communication ...read more

The 12 factors approach is a methodology for building modern, scalable, and maintainable microservices.

• Codebase: One codebase tracked in revision control, many deploys

• Dependencies: Explicitly declare and isolate dependencies

• Config: Store config in the environment

• Backing services: Treat backing services as attached resources

• Build, release, run: Strictly separate build and run stages

• Processes: Execute the app as one or more stateless processes

• Port binding: Export services via p...read more

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

L3 fabric is a network architecture that provides high-speed and low-latency connectivity between devices. COOP is a protocol used for failover and redundancy in networking.

• L3 fabric is a type of network architecture that uses Layer 3 routing to provide high-speed and low-latency connectivity between devices.

• It is designed to be scalable and flexible, allowing for easy expansion and modification of the network.

• COOP (Cluster Over the Wire Protocol) is a protocol used for failo...read more

Java 16 and Spring Boot 2.5 are the latest versions with new features and improvements.

• Java 16 introduces Records, Pattern Matching for instanceof, and Vector API among others.

• Spring Boot 2.5 includes support for Java 16, improved startup time, and better error messages.

• Other new features in Spring Boot 2.5 include support for Kotlin 1.5, Micrometer 1.7, and Spring Data 2021.0.

I am proficient in Civil3D and have extensive experience in using it for designing and drafting civil engineering projects.

• Expertise in creating and editing surfaces, alignments, profiles, and corridors

• Ability to generate 3D models and perform earthwork calculations

• Experience in creating plan and profile sheets, cross-sections, and quantity takeoffs

• Familiarity with Civil3D add-ons such as AutoTURN and Hydraflow

• Proficient in using Civil3D for various civil engineering projects...read more

A thread pool is a group of threads that can be reused to execute multiple tasks concurrently.

• Define a task interface that encapsulates the work to be done

• Create a queue to hold tasks

• Create a fixed number of threads in the pool

• Each thread should loop indefinitely, taking tasks from the queue and executing them

• Use synchronization primitives to ensure thread safety

• Consider using a thread-safe data structure for the task queue, such as a concurrent queue

• Consider using a thread-s...read more

CAN bus off is a state where communication between nodes on a CAN bus is lost. It can be recovered by resetting the bus or fixing the underlying issue.

• CAN bus off occurs when a node on the bus detects an error and goes into a fault state.

• This can happen due to issues like a short circuit, open circuit, or excessive noise on the bus.

• To recover from CAN bus off, the bus needs to be reset or the underlying issue needs to be fixed.

• Resetting the bus involves sending a sequence of ...read more

Engineering calculations involve analyzing data, applying formulas, and solving problems to design and optimize systems.

• Identifying the problem or goal of the calculation

• Gathering relevant data and information

• Applying appropriate formulas and equations

• Performing calculations accurately

• Interpreting results and making recommendations

• Iterating and refining calculations as needed

Leaf and spine architecture is a network topology used in Cisco ACI for scalable and efficient data center networking.

• Leaf switches connect to spine switches, which then connect to the core network.

• Leaf switches handle traffic within their own pod, while spine switches handle traffic between pods.

• ACI uses a 2-tier spine-leaf architecture for scalability and flexibility.

• The spine switches act as the routing backbone, while the leaf switches provide access to endpoints.

• ACI allo...read more

Linq expression to fetch desired results

• Use 'Where' to filter data based on conditions

• Use 'Select' to project data into desired format

• Use 'OrderBy' or 'OrderByDescending' to sort data

• Use 'Skip' and 'Take' to implement pagination