20+ R Systems International Senior Software Engineer Interview Questions and Answers

Find the pair of actors who acted together for the most time in a SQL table.

• Join the casting table with itself on movie_id to get pairs of actors who acted together.

• Calculate the total time they acted together by summing the durations of their movies.

• Order the results by total time and return the pair with the highest duration.

Questions on Ajax, JS code for AJAX, hoisting, and related keywords for Senior Software Engineer role.

• Ajax is a technique for creating fast and dynamic web pages without reloading the entire page.

• JS code for AJAX involves creating an XMLHttpRequest object, defining a callback function, and sending a request to the server.

• Hoisting is a JS mechanism where variables and function declarations are moved to the top of their scope.

• Related keywords include let, const, var, function, ...read more

Dependency injection is a design pattern where components are provided with their dependencies rather than creating them internally.

• Dependency injection helps in achieving loose coupling between components.

• It makes components easier to test by allowing for easier mocking of dependencies.

• Use cases include injecting database connections, logging services, and external API clients into components.

Data seeding in Entity Framework involves pre-populating database tables with initial data. Mapping tables with entities involves defining relationships between database tables and entity classes.

• Data seeding in Entity Framework can be done using the 'Seed' method in the 'Configuration' class of the DbContext.

• To map tables with entities, use data annotations or Fluent API to define relationships between entities and database tables.

• For example, using data annotations like [Ta...read more

React program to change div background color if both input boxes > 10

• Create a state for each input box

• Add onChange event to each input box to update state

• Use useEffect to check if both input values are greater than 10

• If true, update state to change div background color

SOLID principles help in creating maintainable, scalable, and flexible software.

• SOLID principles help in creating software that is easier to maintain and extend.

• Single Responsibility Principle (SRP) ensures that a class has only one reason to change, leading to more modular and cohesive code.

• Open/Closed Principle (OCP) states that a class should be open for extension but closed for modification, allowing for easy changes and additions without altering existing code.

• Violating ...read more

Singleton design pattern ensures a class has only one instance and provides a global point of access to it.

• Create a private static instance of the class within the class itself.

• Provide a public static method to access the instance.

• Ensure the constructor of the class is private to prevent instantiation from outside the class.

• Example: Singleton pattern is commonly used in database connections to ensure only one connection is established.

Debugging a published dll involves using tools like Visual Studio debugger and logging mechanisms.

• Use Visual Studio debugger to attach to the process using the published dll

• Set breakpoints in the code to pause execution and inspect variables

• Use logging mechanisms to track the flow of execution and identify issues

• Check for any exceptions or errors thrown by the dll

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

• It allows objects to be created with their dependencies rather than creating them inside the object.

• It makes code more testable and maintainable.

• Example: Instead of creating a database connection inside a class, pass it as a parameter during object creation.

Yes, it should be immutable.

• Immutable keys ensure that the hashcode of the key remains constant, which is important for efficient hashmap operations.

• If a key is mutable, its hashcode can change during its lifetime, leading to unexpected behavior in the hashmap.

• Examples of immutable keys include String, Integer, and other wrapper classes.

Lambda is an anonymous function while method reference refers to an existing method.

• Lambda expressions are used to create anonymous functions that can be passed as arguments to methods or stored in variables.

• Method references are used to refer to an existing method by name instead of defining a new lambda expression.

• Lambda expressions are more flexible and can be used to create functions with any number of parameters, while method references can only refer to methods with mat...read more

Design principles are guidelines for designing software solutions, while design patterns are reusable solutions to common design problems.

• Design principles are high-level guidelines that help in designing software solutions that are scalable, maintainable, and efficient.

• Design patterns are reusable solutions to common design problems that have been proven to be effective in various scenarios.

• Examples of design principles include SOLID principles, DRY (Don't Repeat Yourself), ...read more

Static variables are shared among all instances of a class, while volatile variables are used for synchronization.

• Static variables are declared with the 'static' keyword and retain their value across multiple function calls.

• Volatile variables are used to indicate that a variable's value can be modified by multiple threads.

• Static variables are stored in the data segment of memory, while volatile variables are stored in the stack or heap.

• Static variables are initialized only on...read more

Oops concepts in real life refer to the principles of object-oriented programming applied to everyday scenarios.

• Encapsulation: Keeping related data and methods together to protect them from outside interference. Example: A car's engine is encapsulated within the car's body.

• Inheritance: Allowing a new class to inherit properties and behaviors from an existing class. Example: A child inheriting traits from their parents.

• Polymorphism: Objects of different classes can be treated ...read more

MVC is a design pattern for organizing code in a web application, while WebAPI is a framework for building HTTP services.

• MVC stands for Model-View-Controller and is used for structuring code in a web application

• WebAPI is a framework for building HTTP services that can be accessed by various clients

• MVC is typically used for creating web applications with user interfaces, while WebAPI is used for creating APIs that can be consumed by different clients

• MVC is more focused on the ...read more

Factory pattern is a creational design 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 pattern is used to create objects without specifying the exact class of object that will be created.

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

• Commonly used in situations where a class can't anticipate the class of objects it must create.

• Examples include GUI f...read more

Dependency injection is a design pattern where components are given their dependencies rather than creating them internally.

• Allows for better code reusability and testability

• Reduces coupling between components

• Promotes separation of concerns

• Examples: Constructor injection, Setter injection, Interface injection

serialversionuid is a unique identifier used for serialization and deserialization of Java objects.

• serialversionuid is a static field in a class that implements Serializable interface

• It is used to ensure that the same class is used for deserialization as was used for serialization

• If serialversionuid is not specified, JVM generates it based on class structure which can cause issues if class structure changes

• It is recommended to specify serialversionuid for all Serializable cla...read more

Cyclic dependency in Spring

• Cyclic dependency occurs when two or more beans depend on each other directly or indirectly

• It can cause runtime errors like StackOverflowError or BeanCurrentlyInCreationException

• To resolve, use setter injection or constructor injection instead of field injection

• Use @Lazy annotation to delay bean initialization

• Use @Autowired(required = false) to break the cycle

SOLID is a set of design principles to make software more maintainable, scalable, and flexible.

• S - Single Responsibility Principle: A class should have only one reason to change.

• O - Open/Closed Principle: Software entities should be open for extension but closed for modification.

• L - Liskov Substitution Principle: Subtypes should be substitutable for their base types.

• I - Interface Segregation Principle: Clients should not be forced to depend on interfaces they do not use.

• D - D...read more