100+ Module Lead Interview Questions and Answers

Answering technical questions on Linux, SQL server, and Java.

• Command in Linux: ls - lists files and directories in a directory

• Indexing in SQL server: improves query performance by reducing the number of disk I/O operations

• Thread dump in core Java: a snapshot of all the threads that are currently executing in a Java Virtual Machine (JVM)

• Difference between di and df in Linux: di shows disk usage by inode while df shows disk usage by file system

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() select new { employee.Name, department.Name }

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 behavior if sharing is not specified.

• Example: A class that ...read more

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.

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

UNION combines the result sets of two or more SELECT statements, while UNION ALL does the same but includes duplicate rows.

• UNION removes duplicate rows from the result set, while UNION ALL includes all rows

• UNION is slower than UNION ALL because it performs a distinct operation

• UNION requires that all SELECT statements have the same number of columns with compatible data types

• Example: SELECT column1 FROM table1 UNION SELECT column1 FROM table2;

• Example: SELECT column1 FROM table...read more

Docker is a containerization platform that allows developers to package, deploy, and run applications in isolated environments.

• Docker uses containerization to create lightweight, portable environments for applications

• Docker images are built using Dockerfiles, which specify the application and its dependencies

• Docker build command: docker build

• Docker containers can be run locally or in the cloud, and can be easily scaled up or down

• Docker Hub is a repository for Docker images, ...read more

Duplicate characters in a string can be identified using a single loop by utilizing a set to track seen characters.

• Use a Set: Initialize an empty set to keep track of characters that have been seen as you iterate through the string.

• Check for Duplicates: For each character, check if it is already in the set. If it is, it’s a duplicate; if not, add it to the set.

• Example: For the string 'hello', as you loop through, 'h' and 'e' are added to the set, but 'l' will be identified as...read more

I ensure SLA adherence and effective client communication through structured processes and proactive engagement during escalations.

• Establish clear escalation protocols to identify critical issues quickly.

• Maintain regular updates with clients, providing timely information on the status of their concerns.

• Utilize a ticketing system to track SLA metrics and ensure compliance.

• Example: In a recent project, I implemented daily stand-ups during a critical escalation, which improved t...read more

A real-time example of object-oriented programming with inheritance, encapsulation, and polymorphism.

• A car is an object that inherits properties from a vehicle class

• Encapsulation ensures that the car's internal workings are hidden from the user

• Polymorphism allows the car to have different behaviors based on the context

• For example, a car can be a sports car or a family car, each with different properties and behaviors

A weak entity set is an entity set that does not have sufficient attributes to form a primary key on its own.

• Weak entity sets depend on another entity set (strong entity set) to form a primary key.

• They have a partial key which is a set of attributes that can uniquely identify entities within the weak entity set.

• Examples include 'Order Item' which depends on 'Order' entity set to uniquely identify each item.

• Another example is 'Dependent' entity set which depends on 'Employee' ...read more

Code to throw ConcurrentModificationException and how to avoid it

• Iterating over a collection and modifying it at the same time can throw ConcurrentModificationException

• To avoid it, use Iterator to iterate over the collection and then modify it

• Alternatively, use ConcurrentHashMap or CopyOnWriteArrayList for thread-safe iteration

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.

Partitions in Informatica help in parallel processing and improving performance.

• Partitions in databases and Informatica serve different purposes

• Informatica partitions help in parallel processing of data

• Improves performance by distributing data processing across multiple nodes

• Allows for better resource utilization and faster data processing

• Example: Partitioning in Informatica can be used to process large volumes of data efficiently

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 specific use case and design considerations.

sum vs sumx in Power BI, x-Velocity, optimization techniques, project-related questions

• sum is an aggregation function that calculates the total of a column, while sumx is an iterator function that performs a calculation for each row and then aggregates the results

• x-Velocity is a feature in Power BI that optimizes data storage and query performance by compressing and indexing data

• Optimization techniques in Power BI include data modeling, query optimization, and performance tun...read more

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 variables are not included in the serialization process.

• St...read more

Microservice design patterns are architectural patterns that help in designing and implementing microservices.

• Service Decomposition

• API Gateway

• Service Registry

• Circuit Breaker

• Saga Pattern

Display flex is for one-dimensional layouts, while display grid is for two-dimensional layouts.

• Display flex is used for creating layouts in one direction (either row or column)

• Display grid is used for creating layouts in two dimensions (rows and columns)

• Flexbox is more suitable for small-scale layouts, while Grid is better for larger layouts with more complex structures

Java 8 introduced several enhancements in memory management, including the Metaspace and improvements in garbage collection.

• Metaspace replaces PermGen: In Java 8, the PermGen space is replaced by Metaspace, which dynamically resizes based on the application's needs.

• Improved Garbage Collection: Java 8 introduced the G1 garbage collector as the default, optimizing memory management for large heaps.

• Compressed OOPs: Java 8 continues to support compressed ordinary object pointers ...read more

I have extensive experience in core Java and related technologies, focusing on development, frameworks, and best practices.

• Core Java: Proficient in OOP concepts, exception handling, and collections framework. Example: Developed a multi-threaded application using Java Concurrency.

• Spring Framework: Utilized Spring Boot for microservices architecture. Example: Created RESTful APIs for a banking application.

• Hibernate: Implemented ORM with Hibernate for database interactions. Exam...read more

To create project structure using Maven in AEM, follow these steps:

• Create a new Maven project in Eclipse or any other IDE

• Add AEM dependencies in the pom.xml file

• Create a content package using the AEM Maven Archetype

• Add the content package to the project structure

• Build the project using Maven

• Deploy the project to AEM using Maven or Package Manager

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 component

The project follows a microservices architecture.

• The project is divided into small, independent services that communicate with each other through APIs.

• Each service is responsible for a specific task or functionality.

• The architecture allows for scalability, flexibility, and easier maintenance.

• Examples of microservices used in the project include user management, payment processing, and inventory management.

Use Java 8 streams to remove duplicates from an ArrayList of strings efficiently.

• Create an ArrayList of strings with duplicates: List<String> list = Arrays.asList("apple", "banana", "apple", "orange");

• Use Java 8 streams to filter duplicates: List<String> uniqueList = list.stream().distinct().collect(Collectors.toList());

• The 'distinct()' method removes duplicates based on the natural ordering of the elements.

• Print the unique elements: System.out.println(uniqueList); // Output:...read more

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