Tech Mahindra Module Lead Interview Questions and Answers

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 ca...read more

Factory Design Pattern is a creational pattern that provides an interface for creating objects in a superclass, but allows subclasses to alter the type of objects that will be created.

• Factory Design Pattern is used to create objects without exposing the creation logic to the client.

• It provides a way to delegate the instantiation logic to child classes.

• It promotes loose coupling by eliminating the need to bind applicati...read more

Runtime polymorphism is the ability of an object to take on multiple forms during runtime.

• It is achieved through inheritance and method overriding.

• The method called depends on the actual object type at runtime.

• Example: Animal class with a speak() method, and Dog and Cat classes that inherit from Animal and override the speak() method.

• When a Dog object calls speak(), the overridden method in the Dog class is executed.

• Wh...read more

Dependency injection is a design pattern where objects are passed as dependencies rather than being created within a class.

• Reduces coupling between classes

• Increases testability and maintainability

• Allows for easier swapping of dependencies

• Examples: Constructor injection, Setter injection, Interface injection

Yes, I have worked with nUnit framework.

• I have used nUnit for unit testing in C# projects.

• I am familiar with its syntax and assertions.

• I have integrated nUnit with Visual Studio for continuous testing.

• I have used nUnit to test both simple and complex scenarios.

• For example, I used nUnit to test a payment processing system.

• I also used nUnit to test a complex algorithm for data analysis.

Endpoints are URLs that clients use to access resources in a WebAPI.

• Endpoints are the entry points for a WebAPI.

• They define the resources that can be accessed by clients.

• Endpoints are identified by a URL and HTTP method.

• Examples of endpoints include /api/users and /api/products.

• Endpoints can have parameters that are passed in the URL or request body.

WebService is a software system designed to support interoperable machine-to-machine interaction over a network. WebApi is a framework for building HTTP services that can be consumed by a broad range of clients.

• WebService uses SOAP protocol for communication while WebApi uses HTTP protocol.

• WebService is platform-independent while WebApi is platform-dependent.

• WebService supports only XML format while WebApi supports XML...read more

Singleton and static are both design patterns used to create objects with global access, but they differ in their implementation.

• Singleton restricts the instantiation of a class to a single object, while static allows multiple instances.

• Singleton provides a global point of access to the object, while static members are accessed through the class name.

• Singleton can be lazy-loaded, while static members are initialized at...read more

Entity framework supports left/right join to pull details from joinee table.

• Use LINQ to perform left/right join in Entity framework

• Use DefaultIfEmpty() method to perform left join

• Use join...into statement to perform right join

• Example: var result = from employee in context.Employees

• join department in context.Departments on employee.DepartmentId equals department.Id into empDept

• from department in empDept.DefaultIfEmpty()

DI can be achieved through method, constructor, and property level patterns.

• Method level DI involves passing dependencies as method parameters.

• Constructor level DI involves passing dependencies as constructor parameters.

• Property level DI involves setting dependencies as properties of an object.

• Examples of DI frameworks that use these patterns include Spring and Unity.

• Choosing the appropriate pattern depends on the spec

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

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 create...read more

Omnichannel is a marketing strategy that provides a seamless and integrated customer experience across all channels.

• Omnichannel focuses on creating a consistent brand experience across all channels

• It involves integrating online and offline channels such as social media, email, mobile, and physical stores

• Customers can interact with the brand through any channel and receive a consistent experience

• Examples include Starbuc...read more

Web to Case is a Salesforce feature that allows customers to submit support cases through a web form.

• Web to Case creates a case record in Salesforce from information submitted through a web form.

• The web form can be customized to include specific fields and validation rules.

• Web to Case can be integrated with email-to-case to ensure all customer inquiries are captured in Salesforce.

• Examples of industries that use Web to ...read more

With sharing and without sharing are keywords used in Apex to specify sharing rules for a class.

• With sharing enforces the sharing rules of the current user, while without sharing ignores them.

• With sharing is used for classes that access or modify data that belongs to multiple users, while without sharing is used for utility classes or classes that only access data owned by the current user.

• With sharing is the default b...read more

Without sharing keyword is used in Apex to bypass sharing rules and access all data.

• Used in classes that need to access all data regardless of sharing rules

• Can be used in batch classes, trigger handlers, and unit tests

• Should be used with caution as it can compromise data security

• Example: Database.delete([SELECT Id FROM Account], false);

Static and transient keywords are used in Java programming language for different purposes.

• Static keyword is used to create class-level variables and methods that can be accessed without creating an instance of the class.

• Transient keyword is used to indicate that a variable should not be serialized when the object is converted to a byte stream.

• Static variables are shared among all instances of a class, while transient ...read more

Field level securities in Aura components

• Use Lightning Data Service to enforce CRUD and FLS

• Use Apex to enforce additional security logic

• Use Lightning Design System to control visibility of fields

• Use custom validation rules to enforce business logic

• Use sharing rules to control record access

Field-level security can be maintained using profiles, permission sets, and sharing rules.

• Profiles can be used to restrict access to fields for a group of users.

• Permission sets can be used to grant additional access to specific fields for certain users.

• Sharing rules can be used to extend access to fields beyond the default sharing settings.

• Validation rules can also be used to enforce data integrity and security at the

LDS stands for Local Data Store.

• LDS is a database that stores data locally on a device.

• It is commonly used in mobile applications to store data offline.

• LDS can be used to store user preferences, cached data, and other information.

• Examples of LDS include SQLite and Realm.

force:createRecord allows creation of records without Apex code.

• Saves time and effort by eliminating the need for Apex code

• Allows for easy creation of records from custom or standard objects

• Can be used in Lightning Experience, Salesforce mobile app, and Communities

• Can prepopulate fields with default values

• Can be used with custom Lightning components

• Example: Creating a new Account record from a custom Lightning componen