4500+ Senior Software Engineer Interview Questions and Answers

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

Four necessary and sufficient conditions for deadlock

• Mutual exclusion: Resources cannot be shared between processes. Example: Process A holding Resource 1 and waiting for Resource 2, while Process B holding Resource 2 and waiting for Resource 1.

• Hold and wait: Processes hold resources while waiting for others. Example: Process A holding Resource 1 and waiting for Resource 2, while Process B holding Resource 2 and waiting for Resource 3.

• No preemption: Resources cannot be forcib...read more

A base class is a class that is used as a starting point for creating other classes. It can be inherited by other classes.

• Base class provides common attributes and methods that can be inherited by other classes

• Derived classes can extend or override the functionality of the base class

• Example: Animal can be a base class with attributes like name and methods like eat, sleep

BlockingQueue is a thread-safe queue that blocks when it is full or empty.

• BlockingQueue is part of the Java Concurrency API.

• It provides methods like put() and take() to add and remove elements from the queue.

• When the queue is full, put() blocks until space becomes available.

• When the queue is empty, take() blocks until an element is available.

• It is commonly used in producer-consumer scenarios.

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

• Used to restrict the instantiation of a class to one object

• Commonly used in logging, caching, thread pools, database connections

• Implemented by creating a static instance of the class and a private constructor to prevent external instantiation

Assert commands in Selenium are used to verify the expected result of a test case, while verify commands are used to check for the presence of an element without halting the test execution.

• Assert commands halt the test execution if the verification fails, while verify commands continue with the test execution even if the verification fails.

• Assert commands are used to validate the expected result of a test case, while verify commands are used to check for the presence of an el...read more

O-Auth is an open standard for authorization. Our project uses token-based authentication for security.

• O-Auth is used to allow users to grant access to their resources without sharing their credentials.

• It uses tokens for authentication instead of passwords.

• Our project uses token-based authentication for security purposes.

• Token-based authentication involves generating a unique token for each user that is used to authenticate their requests.

Different ways to send data view to controller

• Using form submission

• Using AJAX requests

• Using URL parameters

• Using cookies or local storage

• Using web sockets

The number of max and min approvals required in a release pipeline depends on the organization's policies and the complexity of the release.

• The number of approvals required can vary depending on the stage of the pipeline.

• Some organizations may require multiple levels of approval for critical releases.

• The number of approvals can also depend on the size and complexity of the release.

• Automation can help streamline the approval process and reduce the number of required approvals.

Spring Boot is a framework for building standalone, production-grade Spring-based applications.

• Annotations used in Spring Boot include @SpringBootApplication, @RestController, @Autowired, @Component, @Configuration, @EnableAutoConfiguration, and more.

• Validation in Spring Boot can be done using annotations such as @NotNull, @Size, @Min, @Max, and @Pattern.

• Spring Boot also provides built-in support for validation using the javax.validation API.

• Spring Boot's validation can be cu...read more

Flask is lightweight and good for small projects, while Django is more robust and suitable for larger projects.

• Flask is good for small projects with simple requirements

• Django is more suitable for larger projects with complex requirements

• Flask is lightweight and flexible, allowing for more customization

• Django has a lot of built-in features and is more opinionated

• Flask is better for RESTful APIs and microservices

• Django is better for full-stack web applications

• Examples of Flask ...read more

LinkedList is preferred for constant modification due to faster insertion and deletion times.

• LinkedList is preferred for constant modification because it has faster insertion and deletion times compared to ArrayList.

• LinkedList allows for easy insertion and deletion of elements without the need to shift other elements, making it more efficient for constant modifications.

• ArrayList is better for random access and iterating through elements, while LinkedList is better for frequen...read more

Value types hold the data directly, while reference types hold a reference to the data.

• Value types are stored on the stack, while reference types are stored on the heap.

• String is a reference type in .NET.

• Value types include int, float, and bool.

• Reference types include arrays, classes, and interfaces.

Authentication was implemented using JWT tokens and OAuth 2.0. Tech stack includes Node.js, Express, MongoDB, and React.

• JWT tokens were used for user authentication and authorization.

• OAuth 2.0 was used for third-party authentication.

• Node.js and Express were used for the backend.

• MongoDB was used for the database.

• React was used for the frontend.

The software architecture of the project involves a microservices-based approach with a combination of RESTful APIs and message queues for communication.

• The project follows a microservices architecture to enable scalability and flexibility.

• RESTful APIs are used for communication between different services.

• Message queues like Kafka or RabbitMQ are utilized for asynchronous communication and decoupling of services.

• Certain design decisions were made to ensure high availability, ...read more

Watcher is used to monitor changes in variables during runtime, while breakpoint is used to pause program execution at a specific line of code.

• Watcher is used to track the value of a variable or expression during program execution.

• Breakpoint is used to pause the program at a specific line of code to allow for debugging.

• Watchers are typically set up in debugging tools like IDEs, while breakpoints are set by the developer in the code itself.

• Example: Setting a watcher on a varia...read more

The order of output is fs, process, setTimeout, setInterval, promise.

• fs module is synchronous and will output first

• process is next in line

• setTimeout will be executed after process

• setInterval will be executed after setTimeout

• promise will be executed last

A value converter in WPF is used to convert data from one type to another for binding purposes.

• Converts data between different types for data binding

• Implements the IValueConverter interface in WPF

• Can be used to format data for display in UI elements

• Example: converting a boolean value to a visibility enum for showing/hiding elements

Program to change background color on button click in Angular

• Create a button in Angular template

• Add click event listener to the button

• Use setInterval() function to change background color after every 0.5 sec

• Use ngStyle directive to change background color dynamically

Count the number of repeated integers in an array

• Iterate through the array and use a hash table to keep track of the count of each number

• Return the count of numbers with a count greater than 1

To make an object immutable, use final keyword for fields and provide only getters. To make a collection immutable, use Collections.unmodifiableList() or similar methods.

• Use final keyword for fields in the object to prevent them from being modified

• Provide only getters for the fields to ensure they cannot be changed externally

• For collections within the object, use Collections.unmodifiableList() or similar methods to create an immutable view of the collection

I manage load and system interactions using async programming, load balancing, and efficient resource management.

• Utilize asynchronous programming to handle multiple requests without blocking, e.g., using async/await in JavaScript.

• Implement load balancing techniques, such as round-robin or least connections, to distribute traffic evenly across servers.

• Use message queues (e.g., RabbitMQ, Kafka) to decouple services and manage communication between systems asynchronously.

• Monitor...read more

Creating a reusable modal component in React JS with accessibility and styling considerations.

• Use functional components and hooks for state management.

• Implement props for dynamic content: <Modal title='My Modal' content='Hello World' />.

• Add a backdrop for better user experience and to focus on the modal.

• Include keyboard accessibility: close modal on 'Escape' key press.

• Style the modal using CSS or a CSS-in-JS library for better customization.

Before commit and After commit Microflows are used in Mendix to perform actions before and after committing changes to the database.

• Before commit Microflows are executed before the changes are committed to the database.

• They are used to perform validations, calculations, or any other actions that need to be done before saving the data.

• After commit Microflows are executed after the changes are committed to the database.

• They are used to perform additional actions, such as sendin...read more

A function pointer is a variable that stores the memory address of a function.

• Function pointers can be used to pass functions as arguments to other functions.

• Syntax: return_type (*pointer_name)(parameter_list);

• Example: int (*func_ptr)(int, int) = &add;

• Example: int result = (*func_ptr)(2, 3);

Questions related to Java programming language and Spring framework

• Inheritance is a mechanism in Java where a class acquires the properties of another class

• Spring Boot is a popular framework for building web applications in Java

• Advantages of Spring Boot include easy configuration, auto-configuration, and embedded servers

• Spring annotations are used to provide metadata to the Spring framework

• Some common Spring annotations include @Autowired, @Controller, and @Service

• Design patt...read more

JIT compiles code at runtime while AOT compiles code during build time.

• JIT stands for Just-In-Time compilation and compiles code at runtime.

• AOT stands for Ahead-Of-Time compilation and compiles code during build time.

• JIT is used in development mode while AOT is used in production mode.

• JIT compiles templates and components on the fly while AOT compiles them before runtime.

• AOT generates smaller and faster code compared to JIT.