100+ Module Lead Interview Questions and Answers

Various types of joins in SQL include inner join, left join, right join, and full outer join.

• Inner join: Returns rows when there is a match in both tables.

• Left join: Returns all rows from the left table and the matched rows from the right table.

• Right join: Returns all rows from the right table and the matched rows from the left table.

• Full outer join: Returns rows when there is a match in either table.

Liskov Principle is a principle of object-oriented programming that states that objects of a superclass should be replaceable with objects of its subclasses without affecting the correctness of the program.

• Named after Barbara Liskov, a computer scientist who introduced the principle in 1987

• Also known as Liskov Substitution Principle (LSP)

• Helps in designing classes that are easy to extend and maintain

• Violation of LSP can lead to unexpected behavior in the program

• Example: If a ...read more

Spring Boot provides easy and efficient ways to create RESTful services.

• Create a Spring Boot project with Spring Web dependency

• Add @RestController annotation to the controller class

• Use @RequestMapping annotation to map HTTP requests to methods

• Return data using ResponseEntity class

• Use @PathVariable annotation to get dynamic values from URL

• Use @RequestBody annotation to get data from request body

• Use @PostMapping, @GetMapping, @PutMapping, @DeleteMapping annotations for respecti...read more

Improving application performance

• Identify and optimize slow database queries

• Minimize network requests and optimize data transfer

• Use caching to reduce server load and improve response time

• Optimize code by removing unnecessary loops and improving algorithms

• Use a content delivery network (CDN) to improve page load times

• Implement load balancing to distribute traffic evenly across servers

• Use profiling tools to identify performance bottlenecks

• Upgrade hardware or infrastructure if n...read more

Clustered index determines the physical order of data in a table, while non-clustered index does not.

• Clustered index physically reorders the table data based on the indexed column

• Non-clustered index creates a separate structure to store the index data

• Clustered index is faster for retrieval but slower for insert and update operations

• Non-clustered index is slower for retrieval but faster for insert and update operations

Select alternate rows from SQL

• Use the modulo operator to filter alternate rows

• Add a WHERE clause with the modulo operator

• Example: SELECT * FROM table WHERE id % 2 = 0

• Example: SELECT * FROM table WHERE MOD(id, 2) = 0

App Center is a mobile app development platform that helps build, test, and distribute apps.

• It offers features like crash reporting, analytics, and push notifications.

• Developers can integrate App Center with their code repositories and CI/CD pipelines.

• It supports multiple platforms including iOS, Android, and Windows.

• App Center also provides a marketplace for third-party services and plugins.

• Examples of companies using App Center include Microsoft, Adobe, and Honeywell.

SOAP is a protocol while REST is an architectural style for web services.

• SOAP is XML-based while REST uses JSON or XML.

• SOAP requires more bandwidth and processing power than REST.

• SOAP has built-in error handling while REST relies on HTTP error codes.

• SOAP supports both stateful and stateless communication while REST is stateless.

• SOAP is more secure than REST due to its built-in security features.

• Examples of SOAP-based web services include Amazon Web Services and eBay.

• Examples ...read more

Data structures are used to organize and store data in a way that enables efficient access and modification.

• Common data structures include arrays, linked lists, stacks, queues, trees, and graphs.

• Arrays are used to store a collection of elements of the same data type.

• Linked lists are used to store a collection of elements where each element points to the next element in the list.

• Stacks are used to store elements in a last-in-first-out (LIFO) order.

• Queues are used to store elem...read more

A jar file contains compiled Java code while a pom file is used for managing dependencies and build configuration.

• A jar file is an archive file that contains compiled Java code, resources, and metadata.

• A pom file is an XML file used by Maven to manage dependencies and build configuration.

• A jar file is created by compiling Java code using a compiler like javac.

• A pom file is created manually or generated by a build tool like Maven.

• A jar file can be executed using the java comma...read more

Yes, we can call queueable class from batch class.

• Batch class can call a queueable class to perform additional processing after the batch job completes.

• Queueable class can be called from the finish method of the batch class.

• This allows for asynchronous processing of data.

• Example: Batch class processes records and calls a queueable class to send email notifications.

TCP 3-way handshake establishes a reliable connection between two devices. ARP resolves IP addresses to MAC addresses.

• TCP 3-way handshake involves SYN, SYN-ACK, and ACK packets

• SYN packet is sent by the client to the server to initiate the connection

• SYN-ACK packet is sent by the server to the client to acknowledge the request and send its own SYN packet

• ACK packet is sent by the client to the server to confirm the connection

• ARP resolves IP addresses to MAC addresses by broadcas...read more

Behaviors, custom renderers, and triggers are tools used in Xamarin.Forms to customize the appearance and behavior of controls.

• Behaviors allow you to add functionality to controls without subclassing them.

• Custom renderers allow you to create platform-specific renderers for controls.

• Triggers allow you to change the appearance or behavior of controls based on certain conditions.

• Behaviors and triggers can be used together to create complex interactions.

• Custom renderers are often...read more

Challenges in TOSCA include complex test case design, limited community support, and integration issues.

• Complex test case design due to the graphical representation of test scenarios

• Limited community support for issue resolution and best practices

• Integration challenges with other tools and technologies in the testing ecosystem

LINQ stands for Language Integrated Query.

• LINQ is a set of features introduced in .NET Framework that allows for querying data from different data sources using a uniform syntax.

• LINQ can be used to query objects, databases, XML, and more.

• LINQ provides a consistent model for working with data regardless of the data source.

• Example: var query = from c in customers where c.City == 'London' select c;

The .NET Framework is a software framework developed by Microsoft that provides a large library of pre-coded solutions to common programming problems.

• Developed by Microsoft

• Provides a large library of pre-coded solutions

• Supports multiple programming languages

• Used for building applications for Windows, web, mobile, and cloud

• Consists of Common Language Runtime (CLR) and class library

Unit testing involves testing individual units of code to ensure they function as expected.

• Identify the units of code to be tested

• Write test cases for each unit

• Execute the tests and analyze the results

• Use testing frameworks like JUnit or NUnit

• Mock dependencies to isolate the unit being tested

• Test for edge cases and error handling

• Ensure code coverage is sufficient

Several native features have been developed.

• Native camera app with advanced features

• Built-in voice assistant with natural language processing

• Gesture-based navigation system

• Screen recording and screenshot tools

• Biometric authentication options

• Augmented reality capabilities

We use JOIN query to link tables in SQL.

• JOIN query combines rows from two or more tables based on a related column between them.

• Types of JOINs include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN.

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

• Example: SELECT * FROM customers JOIN orders ON customers.customer_id = orders.customer_id;

Application security can be ensured through various measures.

• Implementing secure coding practices

• Using encryption for sensitive data

• Regularly updating software and patches

• Implementing access controls and authentication mechanisms

• Conducting regular security audits and testing

• Using firewalls and intrusion detection systems

• Training employees on security best practices

• Implementing a disaster recovery plan

• Performing regular backups

• Using secure hosting and cloud services

Interconnect between microservices involves communication protocols, service discovery, load balancing, and fault tolerance.

• Use communication protocols like HTTP, gRPC, or messaging queues for inter-service communication

• Implement service discovery mechanisms to locate and connect to other microservices dynamically

• Utilize load balancing techniques to distribute incoming requests evenly across multiple instances of a service

• Implement fault tolerance strategies such as circuit b...read more

super is used to refer immediate parent class instance variable or method, while this is used to refer current class instance variable or method.

• super is used to access parent class members, while this is used to access current class members

• super keyword is used to invoke parent class constructor, while this keyword is used to invoke current class constructor

• super keyword is used to differentiate between parent and child class members with same name, while this keyword is use...read more

Clustered index determines physical order of data while non-clustered index has separate structure.

• Clustered index determines the physical order of data in a table while non-clustered index has a separate structure.

• Clustered index is faster for retrieval of data while non-clustered index is faster for retrieval of specific data.

• A table can have only one clustered index while multiple non-clustered indexes can be created.

• Clustered index is created on the primary key by default...read more

To add push notifications, you need to integrate a push notification service into your app.

• Choose a push notification service provider such as Firebase Cloud Messaging or OneSignal

• Integrate the push notification SDK into your app

• Register your app with the push notification service provider

• Create a server-side API to send push notifications to your app

• Handle push notifications in your app's code

MVVM stands for Model-View-ViewModel. It is a design pattern used in software engineering.

• MVVM separates the user interface from the business logic

• Model represents the data and business logic

• View represents the user interface

• ViewModel acts as a mediator between the Model and View

• Types of MVVM include Classic MVVM, Prism MVVM, and ReactiveUI MVVM

A recursive query is a query that refers to itself in order to retrieve data from a database.

• A recursive query is used to retrieve hierarchical data such as organizational structures or family trees.

• It typically involves a common table expression (CTE) in SQL.

• The query continues to execute until a specific condition is met, such as reaching the root node in a tree structure.

• Example: Finding all employees and their managers in a company hierarchy.

Exceptions in TOSCA are handled using Try-Catch blocks and error handling activities.

• Use Try-Catch blocks to handle exceptions in TOSCA scripts.

• Utilize error handling activities like 'Raise Error' or 'Log Message' to manage exceptions.

• Implement custom error messages for better understanding of the issue.

• Use conditional statements to handle specific exceptions based on the scenario.

• Regularly review and update exception handling mechanisms for improved script reliability.

Optimizing a React application involves reducing bundle size, improving rendering performance, and implementing code splitting.

• Use code splitting to load only necessary code for each page

• Minimize bundle size by removing unused dependencies and optimizing images

• Use React.memo and shouldComponentUpdate to prevent unnecessary re-renders

• Use lazy loading to defer loading of non-critical components

• Use server-side rendering to improve initial load time

• Use performance profiling tools...read more

PowerApps can be used to write back, modify, or delete data from a data source.

• PowerApps provides connectors to various data sources like SharePoint, SQL Server, and Excel.

• To write back data, you can use the Patch function in PowerApps.

• To modify data, you can use the Update function in PowerApps.

• To delete data, you can use the Remove function in PowerApps.

• DAX (Data Analysis Expressions) functions can be used to perform calculations and manipulations on data in PowerApps.

ITIL is a framework for IT service management that outlines best practices for IT processes.

• ITIL consists of five stages: Service Strategy, Service Design, Service Transition, Service Operation, and Continual Service Improvement.

• Each stage has its own set of processes and activities that must be followed to ensure effective IT service management.

• Examples of ITIL processes include Incident Management, Problem Management, Change Management, and Service Level Management.

Transport process involves planning, organizing, and executing the movement of goods or people from one place to another.

• Planning the route and mode of transportation

• Organizing the logistics and scheduling

• Executing the actual movement of goods or people

• Monitoring the progress and ensuring timely delivery

Products can be physical or digital and have various attributes such as quality, features, and packaging.

• Physical products include tangible items like clothing, electronics, and furniture.

• Digital products include software, music, and e-books.

• Product attributes include quality, features, packaging, branding, and price.

• Quality can refer to the durability, reliability, and performance of a product.

• Features can include functionality, design, and customization options.

• Packaging ca...read more

Xamarin Profiler is a tool for analyzing and optimizing the performance of Xamarin apps.

• Xamarin Profiler helps identify memory leaks, CPU usage, and other performance issues

• It can be used with both iOS and Android apps

• The tool provides detailed reports and visualizations to help developers optimize their code

• Xamarin Profiler is available as part of the Visual Studio Enterprise subscription

Multiple design patterns were used including Singleton, Factory, and Observer.

• Singleton pattern was used to ensure only one instance of a class is created.

• Factory pattern was used to create objects without exposing the creation logic.

• Observer pattern was used to notify objects of any changes in state.

• Other patterns such as Decorator and Adapter were also used in specific cases.

Redux is a predictable state container for JavaScript apps.

• Redux is used for managing the state of an application in a predictable way.

• It helps in maintaining a single source of truth for the state.

• Redux is commonly used with React to manage the state of components.

• Actions are dispatched to update the state in Redux.

• Reducers specify how the state changes in response to actions.

DevOps for Xamarin involves continuous integration, delivery, and deployment of mobile apps.

• Automated builds and testing using tools like Visual Studio App Center

• Continuous delivery through app store publishing and distribution

• Monitoring and logging for app performance and user feedback

• Collaboration between development and operations teams for seamless app delivery

SSIS is a data integration tool by Microsoft used for ETL operations.

• SSIS stands for SQL Server Integration Services.

• It is used for extracting, transforming, and loading data from various sources.

• It has a visual interface for designing workflows and tasks.

• SSIS packages can be scheduled and executed using SQL Server Agent.

• Examples of SSIS tasks include data cleansing, data migration, and data warehousing.

Exception handling is the process of handling errors and unexpected events in a program.

• It allows a program to gracefully handle errors and prevent crashes.

• It involves catching and handling exceptions using try-catch blocks.

• Common exceptions include null pointer exceptions and arithmetic exceptions.

• Exception handling can improve the reliability and robustness of a program.

Messaging center is a platform for sending and receiving messages between users or systems.

• It allows users to communicate with each other through messages.

• It can be used for notifications, alerts, and updates.

• Messaging center can be integrated with other systems or applications.

• Examples include email, chat applications, and social media messaging.

• It can also be used for automated messaging, such as appointment reminders or order confirmations.

Xamarin is a cross-platform app development tool that allows developers to build native apps for iOS, Android, and Windows using C#.

• Advantages:

• - Code sharing across multiple platforms

• - Native performance

• - Access to native APIs

• - Large community support

• - Integration with Visual Studio

• Disadvantages:

• - Limited access to some platform-specific features

• - Large app size

• - Requires knowledge of C#

• - Licensing fees for enterprise use

• - Limited third-party library support

• - Debugging can be...read more

To change the port in Spring Boot, modify the application.properties file or use command line arguments.

• Modify application.properties file with 'server.port=XXXX'

• Use command line argument '--server.port=XXXX'

• Update port in embedded server configuration in code

SCD Types refer to Slowly Changing Dimensions Types used in data warehousing.

• SCD Type 1: Overwrite the old data with new data

• SCD Type 2: Create a new record for the new data and keep the old record

• SCD Type 3: Add new columns to the existing record to store new data

• SCD Type 4: Create a separate table to store historical data

• SCD Type 6: Combination of Type 1 and Type 2

Kubernetes is an open-source container orchestration platform that automates deployment, scaling, and management of containerized applications.

• Kubernetes is used to manage containerized applications across multiple hosts.

• It provides features like automatic scaling, self-healing, and rolling updates.

• Kubernetes uses a declarative approach to define the desired state of the application.

• It supports various container runtimes like Docker, CRI-O, and containerd.

• Kubernetes has a lar...read more

OOPs is a programming paradigm that focuses on objects and their interactions. SOLID principles are a set of guidelines for OOP design.

• OOPs stands for Object-Oriented Programming

• It emphasizes on objects and their interactions

• SOLID principles are a set of guidelines for OOP design

• SOLID stands for Single Responsibility, Open-Closed, Liskov Substitution, Interface Segregation, and Dependency Inversion

• Single Responsibility Principle (SRP) states that a class should have only one ...read more

SQL query for updating data in a database table.

• Use the UPDATE statement in SQL to modify existing records in a table.

• Specify the table name, column names, and values to be updated in the query.

• Use WHERE clause to specify the condition for which records to update.

• Example: UPDATE table_name SET column1 = value1, column2 = value2 WHERE condition;

Anypoint MQ is a cloud-based message queuing service that enables reliable communication between applications.

• Anypoint MQ uses a publish-subscribe model for message delivery.

• It supports multiple protocols such as JMS, AMQP, and MQTT.

• It provides features like message filtering, dead-letter queues, and message encryption.

• Anypoint MQ can be integrated with MuleSoft's Anypoint Platform for seamless application integration.

• It offers high availability and scalability with automatic...read more

Power BI is a business analytics service by Microsoft that provides interactive visualizations and business intelligence capabilities.

• Power BI allows users to connect to a wide range of data sources

• Users can create custom visualizations and reports

• Power BI offers a variety of features such as data modeling, data transformation, and data analysis

• Projects in Power BI can range from simple dashboards to complex data models

• Examples of Power BI projects include sales dashboards, f...read more