30+ Cybage Senior Software Engineer Interview Questions and Answers

Java is platform independent because it compiles code into bytecode that can run on any system with a JVM, which is platform dependent.

• Java code is compiled into bytecode, which is platform independent

• The JVM interprets the bytecode and translates it into machine code specific to the underlying platform

• This allows Java programs to run on any system with a JVM installed, making Java platform independent

Programs to count frequency of characters in a string, check if a number is power of 3, and SQL query to get highest salary employees by country.

• For frequencyOfChars, use a HashMap to store character counts and iterate through the string.

• For isPowerOf3, keep dividing the number by 3 until it becomes 1 or not divisible by 3.

• For SQL query, use a subquery to get max salary for each country and join with Emp table.

• Example SQL query: SELECT e1.* FROM Emp e1 JOIN (SELECT Country, M...read more

The command to import a pre-exported Docker image into another Docker host is 'docker load'

• Use the 'docker load' command followed by the file path of the exported image tarball to import it into the Docker host

• For example, 'docker load < my_image.tar.gz' will import the image from the file 'my_image.tar.gz'

• Ensure that you have the necessary permissions to access the file and import images on the target Docker host

SOLID principles are a set of five design principles in object-oriented programming to make software designs more understandable, flexible, and maintainable.

• 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: Objects of a superclass should be replaceable with objects of its subclasses without affecting the prog...read more

The most commonly used instructions in a Dockerfile include FROM, RUN, COPY, and CMD.

• FROM: Specifies the base image for the container

• RUN: Executes commands in the container

• COPY: Copies files and directories from the host to the container

• CMD: Specifies the default command to run when the container starts

Abstract class can have implementation while interface only has method signatures.

• Abstract class can have constructors while interface cannot.

• A class can implement multiple interfaces but can only inherit from one abstract class.

• Abstract class can have non-public members while interface only has public members.

• Abstract class is used for creating a base class while interface is used for implementing a contract.

• Example of abstract class: Animal (with abstract method 'makeSound'...read more

ArrayList is non-synchronized and faster, while Vector is synchronized and slower.

• ArrayList is not synchronized, while Vector is synchronized.

• ArrayList is faster than Vector due to lack of synchronization.

• Vector is thread-safe, while ArrayList is not.

• Example: ArrayList<String> list = new ArrayList<>(); Vector<String> vector = new Vector<>();

The @SpringBootApplication annotation is used to mark a class as a Spring Boot application.

• It combines @Configuration, @EnableAutoConfiguration, and @ComponentScan annotations.

• It enables the auto-configuration feature of Spring Boot.

• It starts the Spring application context, which is the core of the Spring Framework.

• It scans the current package and its sub-packages for components to register.

• It serves as the entry point of the Spring Boot application.

Spring Boot offers basic annotations for various functionalities like mapping requests, handling exceptions, defining beans, etc.

• 1. @RestController - Used to define RESTful web services.

• 2. @RequestMapping - Maps HTTP requests to handler methods.

• 3. @Autowired - Injects dependencies into a Spring bean.

• 4. @Component - Indicates a class is a Spring component.

• 5. @Service - Indicates a class is a service component.

• 6. @Repository - Indicates a class is a repository component.

• 7. @Con...read more

The lifecycle of a Docker container involves creation, running, pausing, restarting, and stopping.

• 1. Creation: A Docker container is created from a Docker image using the 'docker run' command.

• 2. Running: The container is started and runs the specified application or service.

• 3. Pausing: The container can be paused using the 'docker pause' command, which temporarily halts its processes.

• 4. Restarting: The container can be restarted using the 'docker restart' command, which stops...read more

Packages in Java help organize code, prevent naming conflicts, and provide access control.

• Organizes code into logical groups for easier maintenance and readability

• Prevents naming conflicts by allowing classes with the same name to coexist in different packages

• Provides access control by using access modifiers like public, private, protected, and default

• Facilitates reusability by allowing classes in one package to be accessed by classes in another package using import statement

Java Strings are immutable to ensure thread safety, security, and optimization.

• Immutable strings prevent accidental changes, ensuring data integrity.

• String pool optimization reduces memory usage by reusing common strings.

• Thread safety is guaranteed as strings cannot be modified concurrently.

• Security is enhanced as sensitive information cannot be altered once set.

Delegate is a type that represents references to methods with a specific parameter list and return type.

• Delegates are similar to function pointers in C++.

• They are used to achieve loose coupling and separation of concerns.

• There are two types of delegates: singlecast and multicast.

• Singlecast delegates can hold references to a single method.

• Multicast delegates can hold references to multiple methods.

• Delegates are commonly used in event handling and callback scenarios.

JIT compiler stands for Just-In-Time compiler, which compiles code during runtime instead of ahead of time.

• JIT compiler improves performance by compiling code on-the-fly as it is needed

• It can optimize code based on runtime conditions and platform specifics

• Examples include Java's HotSpot JIT compiler and .NET's RyuJIT compiler

Garbage collector in Java is a built-in mechanism that automatically manages memory by reclaiming unused objects.

• Garbage collector runs in the background to identify and remove objects that are no longer needed.

• It helps prevent memory leaks and optimize memory usage.

• Examples of garbage collectors in Java include Serial, Parallel, CMS, and G1.

Custom middleware in .NET Core is a piece of code that sits between the request and response pipeline to perform custom operations.

• Custom middleware can be used to add custom headers, logging, authentication, and authorization to the request pipeline.

• Middleware can be added to the pipeline using the Use() method in the Startup.cs file.

• Middleware can be created using classes that implement the IMiddleware interface or by using lambda expressions.

• Middleware can be ordered in th...read more

Temp table is stored in tempdb and table variable is stored in memory.

• Temp table is created using CREATE TABLE statement and can be accessed by multiple sessions.

• Table variable is created using DECLARE statement and can only be accessed within the scope of the batch or procedure.

• Temp table can have indexes and statistics while table variable cannot.

• Temp table is useful for large data sets while table variable is useful for small data sets.

• Temp table can be used in transaction...read more

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

• Allows for easier testing by providing mock dependencies

• Promotes loose coupling between components

• Improves code reusability and maintainability

• Examples: Constructor injection, Setter injection, Interface injection

Spring Boot is a framework that simplifies the development of Java applications by providing a set of tools and conventions.

• Spring Boot eliminates the need for complex configuration by providing defaults for most settings.

• Actuator is a set of tools provided by Spring Boot for monitoring and managing the application.

• Query param is used to pass parameters in the URL of an HTTP request.

• HTTP methods like GET, POST, PUT, DELETE are used to perform different operations on resources...read more

Cybage is a global technology consulting organization specializing in outsourced product engineering services.

• Cybage has a strong focus on software engineering and product development.

• They have a global presence with offices in North America, Europe, and Asia.

• Cybage has expertise in various industries including healthcare, retail, and finance.

• They have won several awards for their work in software engineering and innovation.

React is better than Angular due to its flexibility, performance, and community support.

• React allows for more flexibility in terms of architecture and state management compared to Angular.

• React's virtual DOM leads to better performance by only updating the necessary components, while Angular's two-way data binding can cause performance issues.

• React has a larger and more active community, providing better support and a wider range of resources compared to Angular.

Joins in SQL are used to combine data from two or more tables based on a related column.

• Joins are used to retrieve data from multiple tables in a single query.

• Common types of joins include inner join, left join, right join, and full outer join.

• Join conditions are specified using the ON keyword and can include multiple conditions.

• Aliases can be used to simplify the syntax of join queries.

• Joins can be nested to combine data from more than two tables.

SQL queries are used to retrieve data from a database. Examples include SELECT, INSERT, UPDATE, and DELETE.

• SELECT * FROM customers WHERE city = 'New York'

• INSERT INTO orders (customer_id, order_date, total_amount) VALUES (1, '2021-01-01', 100.00)

• UPDATE products SET price = 10.99 WHERE id = 1

• DELETE FROM orders WHERE id = 5

Secure WEB API in .NET by using authentication, authorization, HTTPS, and input validation.

• Use authentication mechanisms like JWT tokens or OAuth for secure access.

• Implement authorization to control which users have access to specific resources.

• Enable HTTPS to encrypt data transmitted between client and server.

• Implement input validation to prevent injection attacks like SQL injection or cross-site scripting.

Routings in MVC define how the application responds to client requests.

• Routings map URLs to controller actions in MVC framework

• Routes are defined in RouteConfig.cs file in ASP.NET MVC

• Routes can include parameters and constraints

• Example: routes.MapRoute('Default', '{controller}/{action}/{id}', new { controller = 'Home', action = 'Index', id = UrlParameter.Optional })

Garbage collection is an automatic memory management process used in programming languages to reclaim memory occupied by objects that are no longer in use.

• Garbage collection automatically identifies and deletes objects in memory that are no longer needed by the program.

• It helps prevent memory leaks and improves the efficiency of memory usage.

• Examples of programming languages that use garbage collection include Java, C#, and Python.

Remove duplicate words from a given string

• Split the string into individual words

• Use a set to keep track of unique words

• Iterate through the words and add them to the set if not already present

• Convert the set back to an array of strings

Stored procedures are precompiled SQL queries stored in the database, while functions are reusable blocks of code that return a value.

• Stored procedures are used for performing specific tasks or operations in the database.

• Functions are used to encapsulate logic and can be called from within SQL queries or other functions.

• Stored procedures can have input and output parameters, while functions always return a value.

• Stored procedures can modify data in the database, while functio...read more

Dispatch queue is a queue of tasks that are executed in a first-in, first-out order.

• Dispatch queue is used for managing concurrent tasks in iOS and macOS applications.

• It is a way to manage the execution of tasks in a serial or concurrent manner.

• Tasks can be added to a dispatch queue using dispatch_async() or dispatch_sync() functions.

• Dispatch queue can be either serial or concurrent.

• Serial queue executes tasks in a first-in, first-out order, while concurrent queue executes ta...read more