3500+ Senior Software Engineer Interview Questions and Answers

Our code review process involves peer reviews and automated testing. We follow best practices and use manual testing for edge cases.

• Peer reviews are conducted for all code changes before merging into the main branch

• We use automated testing tools like Jest and Enzyme for unit and integration testing

• We follow best practices like writing clean and modular code, using meaningful variable names, and commenting where necessary

• Manual testing is used for edge cases and scenarios that...read more

Dependency Injection is a design pattern used to remove hard-coded dependencies and make code more flexible and testable.

• Dependency Injection is implemented by injecting the required dependencies into a class rather than creating them within the class.

• This can be achieved through constructor injection, setter injection, or interface injection.

• For example, in Java, Spring Framework provides a powerful dependency injection mechanism through its @Autowired annotation.

• Dependency ...read more

Answers to interview questions for Senior Software Engineer

• 1. CASE is used to provide conditional logic in SQL queries, while DECODE is used to perform conditional value substitution.

• 2. Primary keys are used to uniquely identify each record in a database table.

• 3. Procedures and functions are both database objects that encapsulate a series of SQL statements, but functions return a value while procedures do not.

• 4. SELECT MAX(salary) FROM employees WHERE salary < (SELECT MAX(sal...read more

Use dynamic SQL to create table view with more than 60 columns for different profiles

• Use dynamic SQL to generate the CREATE VIEW statement based on the profile requirements

• Iterate through the profile columns and add them to the CREATE VIEW statement dynamically

• Consider using a loop or a mapping function to handle the large number of columns efficiently

IRCTC reserves seats using a complex system of availability checks and booking processes.

• IRCTC uses a combination of real-time availability checks and booking processes to reserve seats.

• The system checks for availability of seats in real-time and reserves them for a short period of time while the booking process is completed.

• IRCTC uses a locking mechanism to ensure that the same seat is not booked by multiple users at the same time.

• The locking mechanism is based on a first-co...read more

Yes, authentication is implemented using OAuth 2.0 protocol.

• OAuth 2.0 protocol is used for authentication.

• Access tokens are issued to authorized clients.

• Refresh tokens are used to obtain new access tokens.

• Authentication is required for all API endpoints.

Troubleshooting application issues requires thorough analysis, communication, and collaboration.

• Identifying the root cause of the issue by analyzing logs, code, and system configurations.

• Communicating effectively with team members to gather information and brainstorm solutions.

• Collaborating with other teams such as DevOps or QA to investigate potential infrastructure or testing issues.

• Utilizing debugging tools and techniques to isolate and fix the problem.

• Documenting the trou...read more

Express.js is a popular Node.js web framework used for building web applications. Body-parser is a middleware used to parse incoming request bodies.

• Express.js is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications.

• It provides a way to handle HTTP requests and responses, routing, middleware, and more.

• Body-parser is a middleware used to parse incoming request bodies in a middleware before your handlers,...read more

Yes, I have worked on Entity Framework.

• I have used Entity Framework version 6.0 in my previous project.

• I have experience in designing and implementing database models using Entity Framework.

• I have used LINQ to query and manipulate data in Entity Framework.

• I have also worked with migrations and code-first approach in Entity Framework.

Generics should be used when you want to create reusable code that can work with different types.

• Generics allow you to write code that can work with different types without sacrificing type safety.

• They provide compile-time type checking, reducing the chances of runtime errors.

• Generics promote code reusability and maintainability by allowing you to write generic algorithms and data structures.

• Using generic classes in .NET can improve performance by avoiding unnecessary boxing ...read more

Singleton class ensures only one instance is created, while static class allows multiple instances.

• Singleton class restricts instantiation of a class to a single object.

• It provides a global point of access to the instance.

• It is useful when only one instance of a class is required throughout the system.

• Singletons can be lazy-loaded or eagerly-loaded.

• Static classes allow multiple instances and are not suitable for maintaining state.

• Static classes are useful for utility function...read more

Interview questions for Senior Software Engineer position

• OOPS concepts include inheritance, polymorphism, encapsulation, and abstraction

• Abstract classes cannot be instantiated while interfaces cannot have implementation

• SQL query to get second highest salary: SELECT MAX(salary) FROM table_name WHERE salary < (SELECT MAX(salary) FROM table_name)

• Index in SQL server is a data structure that improves the speed of data retrieval operations

• Primary key uniquely identifies a record, f...read more

Passing a runtime parameter from one Graph task to another within a Plan with different timings.

• Use Plan variables to store the runtime parameter in Graph task 1

• Set up a trigger in Graph task 2 to read the parameter from the Plan variables

• Ensure that the timings of the Graph tasks are properly synchronized

The interview question covers topics like hashmap implementation in Java 8, bean lifecycle, annotations in Spring framework, HTTP methods, REST API authentication, and disabling junit test cases during deployment.

• HashMap in Java 8 uses an array of linked lists to store key-value pairs, with the hash code of the key determining the index in the array.

• Bean lifecycle in Spring framework involves initialization and destruction phases, managed by the container.

• @Component and @Serv...read more

To find out the system's IP address in Unix, you can use the 'ifconfig' command or the 'ip addr show' command.

• Use the 'ifconfig' command to display the IP address of all network interfaces on the system.

• Alternatively, you can use the 'ip addr show' command to show the IP address information of all network interfaces.

• You can also use tools like 'hostname -I' or 'ip route get 1.2.3.4' to find out the system's IP address.

OOP is a programming paradigm based on the concept of objects, which can contain data in the form of fields and code in the form of procedures.

• OOP focuses on creating objects that interact with each other to solve complex problems

• Objects have attributes (data) and methods (functions) that operate on the data

• Encapsulation, inheritance, and polymorphism are key principles of OOP

• Example: A car object with attributes like color, model, and methods like start(), stop()

Interview questions for Senior Software Engineer

• 1) Largest Palindrom in a substring - use two pointers approach

• 2) Difference between wait and sleep in Thread - wait releases the lock, sleep doesn't

• 3) SQL join queries - inner, outer, left, right, self joins

• 4) Second largest employee salary SQL Query - use subquery or order by and limit

• 5) First level and second level cache in hibernate - first level is session specific, second level is application wide

• 6) Difference between get ...read more

A cursor is used to retrieve and manipulate data from a database, while a while loop is a control structure used to repeat a block of code.

• Cursors are used in database operations, while while loops are used in programming logic.

• Cursors are typically used to iterate over a result set, while while loops can be used for any repetitive task.

• Cursors can be more efficient for large result sets, while while loops are generally simpler and easier to understand.

• Cursors can be used to ...read more

Explanation of differences between programming concepts and techniques.

• Procedure vs Function: Functions return a value while procedures do not.

• Delete vs Truncate: Delete removes rows one by one while truncate removes all rows at once.

• Exit vs In: Exit is used to exit a loop or a program while In is used to pass values into a subprogram.

• Cursor vs Bulk Bind: Cursor fetches one row at a time while Bulk Bind fetches multiple rows at once.

• Cursor vs Collection: Cursor is used to fet...read more

MVC filters are used in projects to handle cross-cutting concerns and provide a way to intercept and modify the behavior of MVC actions.

• MVC filters are attributes that can be applied to controllers or actions.

• They can be used to perform tasks like authentication, authorization, logging, exception handling, etc.

• Filters can be applied globally, at the controller level, or at the action level.

• There are different types of filters in MVC, such as Authorization filters, Action filt...read more

Identifying slow running query in a 1000 line stored procedure

• Use SQL Server Profiler to trace the stored procedure and identify the slow running query

• Check the execution plan of the stored procedure to identify the slow running query

• Use SET STATISTICS TIME ON to measure the execution time of each query in the stored procedure

• Divide the stored procedure into smaller parts and test each part to identify the slow running query

Garbage collector in Java is responsible for automatic memory management.

• Garbage collector automatically reclaims memory by freeing objects that are no longer referenced.

• It runs in the background and identifies unused objects based on reachability.

• Different garbage collection algorithms like Mark and Sweep, Copying, and Generational are used.

• Garbage collector can be tuned using JVM options like -Xmx and -Xms.

• Example: System.gc() can be used to suggest garbage collection, but ...read more

SQL functions return a single value of a specified data type.

• SQL functions can return various data types such as integer, string, date, etc.

• The return type of a function is specified in the function declaration.

• Functions can be used in SELECT, WHERE, and other SQL statements to manipulate data.

• Examples of SQL functions include COUNT, AVG, MAX, MIN, and CONCAT.

• Functions can also be user-defined using the CREATE FUNCTION statement.

Scopes in JavaScript determine the accessibility of variables and functions.

• Global scope: variables and functions declared outside any function are accessible globally

• Local scope: variables and functions declared inside a function are only accessible within that function

• Block scope: variables declared with let and const are only accessible within the block they are declared in

• Function scope: variables declared with var are accessible within the function they are declared in

Partial views are reusable components of a view that can be rendered within other views.

• Partial views are used to break down complex views into smaller, more manageable pieces.

• They can be used to display common elements across multiple views, such as headers or footers.

• Partial views can be rendered within other views using the @Html.Partial() method in ASP.NET MVC.

• They can also be passed data from the parent view using the @Html.Partial() method with a model parameter.

• Partial...read more

I have used the Observer design pattern in my current project.

• Observer pattern is used to establish a one-to-many dependency between objects.

• It allows multiple objects to be notified and updated automatically when a subject object changes its state.

• In my project, we implemented the Observer pattern to notify various components of the system about changes in data.

• For example, when a user updates their profile information, the Observer pattern is used to notify all relevant com...read more

Abstract classes provide a blueprint for other classes to follow and cannot be instantiated.

• Abstract classes are used when we want to provide a common interface for a group of related classes.

• They cannot be instantiated and must be extended by a subclass.

• Abstract methods are declared in the abstract class and implemented in the subclass.

• They can have both abstract and non-abstract methods.

• Example: Animal is an abstract class and Dog, Cat, and Bird are its subclasses.

Ref and out are keywords used in C# to pass arguments by reference instead of value.

• Ref and out are used to pass arguments by reference instead of value

• Ref keyword is used to pass a reference of the variable to the method

• Out keyword is used to pass a reference of the variable to the method and requires the variable to be initialized before use

• Ref keyword can be used to modify the value of the variable passed as an argument

• Out keyword is used when the method needs to return mu...read more

MVC is a software design pattern that separates an application into three main components: Model, View, and Controller.

• MVC stands for Model-View-Controller

• In MVC, Model represents the data and business logic, View represents the user interface, and Controller acts as an intermediary between Model and View

• 3-tier architecture typically consists of Presentation Layer, Business Logic Layer, and Data Access Layer

• In 3-tier architecture, each layer is responsible for specific functi...read more

Indexes are used to improve database performance. Clustered indexes determine the physical order of data, while non-clustered indexes do not.

• Indexes are used to speed up data retrieval operations in a database.

• Clustered indexes determine the physical order of data in a table, while non-clustered indexes do not.

• A table can have only one clustered index, but multiple non-clustered indexes.

• Clustered indexes are generally faster for retrieving large ranges of data, while non-clus...read more

Merge Sort and Quick Sort are sorting algorithms. Merge Sort is stable but slower. Quick Sort is faster but unstable.

• Merge Sort divides the array into two halves, sorts them recursively, and then merges them.

• Quick Sort selects a pivot element, partitions the array around the pivot, and then recursively sorts the subarrays.

• Merge Sort has a time complexity of O(nlogn) and space complexity of O(n).

• Quick Sort has a time complexity of O(nlogn) on average and O(n^2) in the worst ca...read more

No, assigning null to an array makes it empty and its length becomes 0.

• Assigning null to an array makes it empty.

• The length of an empty array is 0.

• Trying to access length property of null will result in an error.

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

• Used when only one instance of a class is required throughout the project

• Provides a global point of access to the instance

• Can be implemented using a private constructor and a static method

• Examples include database connections, configuration settings, and logger classes

JVM architecture includes class loader, bytecode verifier, interpreter, JIT compiler, and runtime data areas. Memory management is done through garbage collection.

• JVM has class loader to load class files and bytecode verifier to check the code for security and correctness.

• Interpreter executes the bytecode and JIT compiler optimizes the code for better performance.

• Runtime data areas include method area, heap, stack, and PC registers.

• Memory management is done through garbage co...read more

OOP stands for Object-Oriented Programming. It is a programming paradigm based on the concept of objects, which can contain data and code.

• Main method can be overloaded in Java by defining multiple methods with the same name but different parameters.

• Abstraction in OOP is the concept of hiding the implementation details and showing only the necessary features of an object. Example: Car as an object with properties like color, model, and methods like start, stop.

• Inheritance in J...read more

I verified the data by comparing the source and destination databases using SQL queries and automated scripts.

• Used SQL queries to check for data consistency between the source and destination databases

• Wrote automated scripts to compare records and identify any discrepancies

• Performed manual spot checks on a sample of transferred data to ensure accuracy

Stored procedures in Snowflake are precompiled SQL code blocks stored in the database for reuse.

• Stored procedures are used to encapsulate complex SQL logic for reuse.

• They can improve performance by reducing network traffic and increasing security.

• Examples of using stored procedures in Snowflake include creating data transformation pipelines and automating data loading processes.

Different types of duplicate checks using SQL queries

• Using DISTINCT keyword to remove duplicate rows

• Using GROUP BY clause to group data and count duplicates

• Using INNER JOIN to identify duplicates between two tables

• Using subqueries to find duplicates within a single table