900+ Technical Lead Interview Questions and Answers

Tech Lead interview questions on requirement analysis, microservices, AWS CDK, auto-scaling, and ElasticSearch.

• Requirement analysis to production deployment flow and tools used

• Auto-scaling in microservices architecture

• Difference between microservices and serverless

• Choosing between monolith and microservices for an enterprise-level application

• Importance of writing documentation, manuals, and tech wiki

• Writing a lambda function using AWS CDK and setting properties for CDK

• Auto-sc...read more

Answering managerial questions for Tech Lead position

• For past issue, explain the problem and how you identified it

• Describe the mitigation strategy and its effectiveness

• For non-compliant code, assess the impact and prioritize fixes

• Communicate the issue to stakeholders and plan for a fix

• For looking to switch, explain the reasons and how it aligns with career goals

I have worked on multiple automation frameworks including Selenium, Appium, and TestNG.

• I have experience in creating and maintaining automated test scripts using Selenium WebDriver for web applications.

• I have also worked with Appium for mobile automation testing.

• TestNG has been my preferred choice for test management and reporting.

• I have also integrated automation scripts with CI/CD pipelines using tools like Jenkins.

• I have experience in creating custom frameworks using Java ...read more

REST API is a web service that uses HTTP methods to interact with resources. GET, PUT, POST, DELETE, MERGE, PATCH are different methods.

• REST API is a stateless architecture that uses HTTP methods to interact with resources.

• GET method is used to retrieve data from a server.

• PUT method is used to update an existing resource on the server.

• POST method is used to create a new resource on the server.

• DELETE method is used to delete a resource from the server.

• MERGE method is used to u...read more

Technical interview questions on Unix and SQL

• To find files in a directory, use the 'find' command

• To count words using grep, use the '-c' option

• To kill a particular process, use the 'kill' command with the process ID

• To find the kernel version and operating system, use the 'uname' command

• The 'top' command is used to monitor system processes and resource usage

• A zombie process is a process that has completed execution but still has an entry in the process table

• Joins in SQL are us...read more

Caching can speed up request response. Popular caches include Redis, Memcached, and browser caching.

• Caching stores frequently accessed data in memory for faster retrieval

• Browser caching stores static assets like images and CSS files

• Redis and Memcached are popular in-memory caching solutions for web applications

• Cache invalidation is important to ensure data consistency

Implementing naming of threads in a multi-threaded OS and implementing rand5 using rand7

• Use thread ID or thread name to name threads in a multi-threaded OS

• Implement a function that generates a random number between 1 and 7

• Use rejection sampling to implement rand5 using rand7

• Ensure thread names are unique to avoid confusion

• Test the implementation thoroughly to ensure correctness

Answering questions related to Technical Lead interview

• I have experience in containerization and orchestration tools like Docker and Swarm, which will help me quickly learn and adapt to Kubernetes

• I have a strong understanding of distributed systems and cloud infrastructure, which are key components of Kubernetes architecture

• Steps to deploy Kubernetes involve setting up a cluster, configuring nodes, installing Kubernetes components, and deploying applications using YAML files

• I...read more

JWT token is used to secure endpoints in REST APIs by providing authentication and authorization.

• JWT stands for JSON Web Token

• It is a compact, URL-safe means of representing claims to be transferred between two parties

• It is used for authentication and authorization

• It contains three parts: header, payload, and signature

• The header contains the algorithm used to sign the token

• The payload contains the claims or information about the user

• The signature is used to verify the authent...read more

To make a thread safe object in Java, use synchronization or locks.

• Use synchronized keyword to ensure only one thread can access the object at a time.

• Use locks to provide more fine-grained control over synchronization.

• Use thread-safe data structures like ConcurrentHashMap or AtomicInteger.

• Avoid using static variables or mutable shared state.

• Consider using immutable objects or thread-local variables.

• Test the thread safety of your code using tools like JUnit or stress testing.

• D...read more

Factors considered before moving to PaaS

• Cost-effectiveness compared to on-premise solutions

• Scalability and flexibility of the platform

• Ease of deployment and management

• Availability of necessary features and integrations

• Security and compliance measures

• Vendor lock-in and portability

• Ability to focus on application development rather than infrastructure management

Technical Lead interview questions on COBOL, DB2, and CICS

• Types of call in COBOL

• File status 39 indicates end-of-file reached

• AICA is Abend-AID CICS Abend RSN (Reason) Code

• Cursor is used to fetch rows from DB2 tables sequentially

• Compiler options include OPTIMIZE, DEBUG, and LIST

• BIND utility is used to bind DB2 programs to database

• Dynamic VSAM file reading can be done using READNEXT function

• -911 SQLCODE indicates deadlock or timeout error

• Research organization before interview

• Int...read more

Angular code to fetch and display JSON response in tabular format.

• Use HttpClient module to make an HTTP GET request to the given URL.

• Subscribe to the response and extract the JSON data.

• Create an Angular component to display the data in a tabular format using HTML and CSS.

Achieve parallel testing in Selenium using Java

• Use TestNG framework to execute tests in parallel

• Create multiple instances of WebDriver

• Use ThreadLocal to maintain thread safety

• Use Selenium Grid to distribute tests across multiple machines

• Configure TestNG XML file to specify parallel execution mode

Abstract classes and interfaces are used to achieve abstraction and provide a blueprint for classes to implement.

• Used abstract class to create a base class for different types of vehicles, with common properties and methods.

• Used interface to define a contract for different payment methods, with each method implementing its own logic.

• Abstract classes are used when we want to provide a default implementation for some methods, while leaving others to be implemented by the derive...read more

Answers to questions related to vacuum technology and design.

• Vacuum is a space devoid of matter. Outgassing is the release of trapped gases from a material in a vacuum.

• Considerations for designing a vacuum chamber include material selection, sealing methods, and pumping speed.

• A virtual leak is a false indication of a leak caused by gas trapped in a chamber or system.

• Virtual leak and outgassing are not the same.

• Venting is the process of releasing gas from a chamber or system t...read more

I have used the built-in scheduler in Azure Data Factory (ADF).

• ADF provides a built-in scheduler that allows you to schedule and orchestrate data integration and data transformation activities.

• The scheduler in ADF supports various scheduling options such as time-based, event-based, and tumbling window triggers.

• You can define the schedule for your pipelines and activities using JSON-based expressions.

• For example, you can schedule a pipeline to run every day at a specific time ...read more

DB activities that can be part of a transaction group

• Insertion of data into a table

• Updating data in a table

• Deletion of data from a table

• Creating or dropping a table

• Altering the structure of a table

• Executing stored procedures

• Executing functions

• Executing triggers

Factors considered before moving to IaaS

• Cost savings compared to on-premise infrastructure

• Scalability and flexibility to meet changing business needs

• Reduced maintenance and management responsibilities

• Access to advanced technologies and features

• Improved disaster recovery and business continuity capabilities

Teradata architecture and performance tuning techniques

• Teradata architecture consists of parsing engine, BYNET, access module processors, and storage

• Performance tuning techniques include indexing, partitioning, and query optimization

• Indexing involves creating indexes on frequently accessed columns

• Partitioning involves dividing large tables into smaller ones for faster access

• Query optimization involves rewriting queries to reduce resource consumption

Explaining @Transactional, Authentication vs Authorization, and Cookies vs Session

• By default, @Transactional rolls back on unchecked exceptions

• Authentication is verifying the identity of a user, while Authorization is granting access to resources based on their role

• Cookies are stored on the client-side, while sessions are stored on the server-side

• Sessions are preferred for security reasons, as cookies can be easily manipulated

• Examples of authentication mechanisms include user...read more

Microservices architecture can improve scalability, flexibility, and fault tolerance of a project.

• Identify the different functionalities of the project and break them down into smaller, independent services

• Use APIs to communicate between services

• Implement containerization and orchestration tools like Docker and Kubernetes

• Ensure each service has its own database to avoid data coupling

• Monitor and manage services individually

• Examples: Netflix, Amazon, Uber

I have worked with various design patterns including MVC, Singleton, Factory, and Observer.

• MVC pattern for separating concerns in web applications

• Singleton pattern for ensuring only one instance of a class is created

• Factory pattern for creating objects without exposing the instantiation logic

• Observer pattern for implementing event-driven architectures

I have used various logging methodologies including centralized logging, structured logging, and event logging.

• Centralized logging using tools like ELK stack and Splunk

• Structured logging using libraries like Serilog and log4net

• Event logging using Windows Event Viewer and Syslog

• Custom logging solutions using database or file storage

• Logging for performance monitoring and debugging purposes

Display days of each month based on user input in OAF page.

• Get the month name input from user

• Use Java Calendar class to get number of days in the month

• Create an array of strings to store the days

• Loop through the days and display them on the page

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

• Create a private constructor to restrict object creation.

• Create a static method to return the single instance of the class.

• Use lazy initialization to create the instance only when needed.

• Ensure thread safety by using synchronized keyword or double-checked locking.

• Commonly used in database connections, logging, and configuration settings.

EC2 is a web service that provides resizable compute capacity in the cloud.

• EC2 stands for Elastic Compute Cloud

• It allows users to rent virtual computers on which to run their own applications

• EC2 instances can be easily scaled up or down based on demand

• To build and deploy on AWS, one can use services like AWS CodeDeploy, AWS CodePipeline, and AWS Elastic Beanstalk

Perl DBI module is used to connect to databases and fetch data from tables.

• Use DBI module to connect to database using appropriate driver, username, password, and database name

• Prepare and execute SQL queries to fetch data from tables using DBI module

• Use fetchrow_array() or fetchrow_hashref() methods to retrieve data from query results

Implement validation checks before saving data to restrict user from entering wrong data.

• Implement client-side validation checks using JavaScript to ensure data entered is in correct format.

• Implement server-side validation checks to ensure data entered is valid and meets business rules.

• Display error messages to the user if data entered is incorrect.

• Disable the save button until all validation checks have passed.

Points to consider when merging two rating scale questions

• Ensure the rating scales have the same range and intervals

• Consider the wording and phrasing of the questions to ensure consistency

• Evaluate if the merged question will provide meaningful and actionable data

• Test the merged question with a sample audience to ensure clarity and understanding

Answering technical questions on Spring XML configuration, bean scopes, Agile method, prime numbers, and hashmap.

• To read property file from Spring XML configuration, use tag

• Bean scopes in Spring are singleton, prototype, request, session, and global-session

• Agile method is an iterative approach to software development

• Prime numbers are numbers that are only divisible by 1 and itself

• Internal working of hashmap involves hashing the key to get an index and storing the value at th...read more

Designing a service layer for a highly scalable application requires careful consideration of architecture and technology choices.

• Use a microservices architecture to break down the application into smaller, more manageable components.

• Implement load balancing and auto-scaling to ensure that the service layer can handle high traffic volumes.

• Choose a technology stack that is well-suited to the specific needs of the application, such as high throughput or low latency.

• Implement ca...read more

Adapter pattern converts the interface of a class into another interface that clients expect.

• Adapter pattern is used to make incompatible interfaces work together.

• It is used when we want to reuse an existing class that doesn't have the interface we need.

• It involves creating a wrapper class that translates the interface of one class into another interface.

• An example is using a USB to Ethernet adapter to connect a computer to a network.

• It is possible to replace it with other pa...read more

The tip and tail checks on the final outputs ensure accuracy and quality.

• Check for any errors or discrepancies in the tip and tail sections of the final outputs.

• Verify that the tip and tail sections are properly aligned and formatted.

• Ensure that all necessary information is included in the tip and tail sections.

• Confirm that the tip and tail sections meet the required standards and specifications.

• Perform a final review of the tip and tail sections to ensure they are error-free...read more

String is immutable to ensure thread safety and security. Yes, we can write our own immutable class.

• String is immutable to prevent accidental modification of data.

• Immutable classes ensure thread safety and security.

• We can write our own immutable class by making all fields final and not providing any setters.

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

We use OAuth2 for authentication and role-based access control for authorization.

• We use OAuth2 protocol for authentication which allows users to grant access to their resources without sharing their credentials.

• For authorization, we implement role-based access control (RBAC) which restricts access based on the user's role.

• RBAC is implemented using JSON Web Tokens (JWT) which contain user's roles and permissions.

• We also use HTTPS protocol to ensure secure communication between...read more

I encourage open communication and active listening to resolve disputes among team members.

• Encourage team members to express their concerns and listen actively to each other.

• Identify the root cause of the dispute and work towards finding a mutually beneficial solution.

• If necessary, involve a neutral third party to mediate the discussion.

• Establish clear communication guidelines and conflict resolution processes within the team.

• Regularly check in with team members to ensure tha...read more

Oracle provides steps to avoid custom part of workflow from being overridden.

• Use the 'freeze' feature to lock the workflow and prevent changes

• Use the 'versioning' feature to create multiple versions of the workflow

• Use the 'access control' feature to restrict access to the workflow

• Use the 'approval' feature to require approval before changes can be made

• Use the 'audit trail' feature to track changes made to the workflow

Yes, I have experience with Jenkins and Cloud Deployment.

• I have used Jenkins for continuous integration and continuous deployment.

• I have experience with setting up Jenkins pipelines for automated deployment.

• I have worked with cloud platforms like AWS and Azure for deploying applications.

• I have used tools like Ansible and Terraform for infrastructure automation.

• I have experience with containerization using Docker and Kubernetes for deployment.

• I have worked with Git for version...read more

Authentication and authorization were handled using a combination of technologies and protocols.

• Used OAuth 2.0 for authentication

• Implemented role-based access control for authorization

• Stored user credentials securely using bcrypt hashing algorithm

• Used JSON Web Tokens (JWT) for session management

• Implemented two-factor authentication for sensitive operations

SQL query optimization involves analyzing and modifying queries to improve performance.

• Identify and eliminate unnecessary or redundant queries

• Use appropriate indexes to speed up data retrieval

• Optimize query structure and syntax

• Avoid using wildcard characters at the beginning of a LIKE statement

• Minimize the use of subqueries

• Use EXPLAIN or query execution plans to identify bottlenecks

• Consider denormalizing tables for frequently accessed data

• Optimize database schema design

• Regula...read more

To move from one Entity Framework version to another, update the NuGet package and make necessary code changes.

• Update the NuGet package to the desired version

• Make necessary code changes to accommodate any breaking changes

• Test thoroughly to ensure the application still works as expected

Customer information will be encrypted using industry-standard encryption algorithms and stored securely.

• Use industry-standard encryption algorithms such as AES or RSA

• Ensure that encryption keys are securely stored and managed

• Implement secure storage mechanisms such as hashing and salting

• Regularly review and update encryption protocols to ensure they remain secure

Free uses metadata stored in the heap to determine the number of memory blocks to delete for arrays.

• Free stores metadata about the size of the allocated memory block in the heap.

• Free uses this metadata to determine the number of memory blocks to delete for arrays.

• For example, if an array of 10 integers was allocated, the metadata would indicate the size of the block as 40 bytes.

• Free would then use this information to delete all 40 bytes of memory allocated for the array.