10+ Portescap Interview Questions and Answers

Java 8 features like lambda expressions and functional interfaces make coding with streams easier and more efficient.

• Lambda expressions allow for concise and readable code when working with streams.

• Functional interfaces like Predicate, Function, and Consumer can be used with streams to perform operations on elements.

• Stream API provides methods like map, filter, and reduce for processing collections of data in a declarative way.

• Parallel streams enable concurrent processing of ...read more

Optional in Java 8 is used to represent a value that may or may not be present, reducing the chances of NullPointerException.

• Optional is used to avoid NullPointerException by explicitly stating whether a value is present or not.

• Commonly used methods with Optional include isPresent(), get(), orElse(), orElseGet(), and map().

• Example: Optional optionalString = Optional.ofNullable("Hello");

Isolation levels in transactions determine the degree to which transactions are isolated from each other. Propagation types define how transactions are propagated between different components.

• Isolation levels include READ UNCOMMITTED, READ COMMITTED, REPEATABLE READ, and SERIALIZABLE.

• Propagation types include REQUIRED, REQUIRES_NEW, SUPPORTS, MANDATORY, and NEVER.

• Isolation levels control the visibility of changes made by other transactions before the current transaction is co...read more

Multiple inheritance is a feature in object-oriented programming where a class can inherit attributes and methods from more than one parent class.

• Allows a class to inherit from multiple parent classes, combining their attributes and methods

• Can lead to the diamond problem where ambiguity arises if two parent classes have a method with the same name

• Achieved in languages like C++ using virtual inheritance or interfaces in languages like Java

Types of dependency injection include constructor injection, setter injection, and interface injection.

• Constructor injection: Dependencies are provided through a class's constructor.

• Setter injection: Dependencies are provided through setter methods.

• Interface injection: Dependencies are provided through an interface method.

Transaction management in Spring Boot ensures data integrity by managing database transactions.

• Spring Boot uses @Transactional annotation to manage transactions

• It ensures that all operations within a transaction are completed successfully or rolled back if an error occurs

• Transactions can be managed programmatically using TransactionTemplate

• Supports different transaction isolation levels like READ_COMMITTED, REPEATABLE_READ, etc.

Design patterns in microservice architecture help in solving common design problems and improving scalability, maintainability, and flexibility.

• Service Registry pattern - used for service discovery and registration

• Circuit Breaker pattern - used for fault tolerance and resilience

• API Gateway pattern - used for routing and load balancing

• Saga pattern - used for managing distributed transactions

• Event Sourcing pattern - used for capturing all changes to an application state as a se...read more

Inter-service communication in microservices involves using protocols like HTTP, gRPC, or messaging queues.

• Microservices communicate with each other through APIs using protocols like HTTP or gRPC.

• Message queues like RabbitMQ or Kafka can be used for asynchronous communication between services.

• Service discovery tools like Consul or Eureka help services locate each other dynamically.

• API gateways can be used to manage and secure communication between services.

• Event-driven archit...read more

RestTemplate is a synchronous client for making HTTP requests, while Feign Client is a declarative HTTP client that simplifies making API calls.

• RestTemplate is part of the Spring framework and requires manual configuration for each request.

• Feign Client is a declarative client that uses annotations to define API endpoints and parameters.

• RestTemplate is synchronous, blocking the calling thread until the response is received.

• Feign Client is asynchronous by default, allowing for ...read more

Steps to write an immutable class

• Make the class final so it cannot be extended

• Make all fields private and final

• Do not provide setter methods for the fields

• Ensure that any mutable objects within the class are also immutable

• If a mutable object must be returned, make a deep copy before returning it

Fault tolerance in microservices ensures system reliability by handling failures gracefully.

• Microservices architecture breaks down applications into smaller, independent services.

• Each microservice is designed to be resilient to failures and can continue to operate even if one service fails.

• Fault tolerance is achieved through redundancy, monitoring, and graceful degradation.

• Examples of fault tolerance mechanisms include circuit breakers, retries, and fallback mechanisms.

Jenkins is a popular open-source automation server used for continuous integration and continuous delivery (CI/CD) pipelines.

• Jenkins is used to automate the building, testing, and deployment of software projects.

• CI/CD pipelines in Jenkins help in automating the software delivery process by integrating code changes frequently and delivering them to production.

• Jenkins allows for the creation of pipelines that define the steps to be executed, such as compiling code, running test...read more

Apache Kafka is a distributed streaming platform that allows for the publishing and subscribing to streams of records.

• Apache Kafka is designed to be highly scalable and fault-tolerant.

• It uses a distributed commit log to store messages.

• Producers publish messages to topics, and consumers subscribe to topics to receive messages.

• Kafka can be used for real-time stream processing, data pipelines, and event sourcing.

• It provides strong durability guarantees and high throughput.

Docker is a platform for developing, shipping, and running applications in containers, which are lightweight, portable, and isolated environments.

• Docker is a tool that allows you to package an application and its dependencies into a standardized unit called a container.

• Containers are isolated environments that contain everything needed to run the application, including code, runtime, system tools, libraries, and settings.

• Containerization helps in ensuring consistency across d...read more

In Spring framework, @primary is used to specify the primary bean to be autowired, while @qualifier is used to specify a specific bean to be autowired.

• Use @Primary when there are multiple beans of the same type and you want to specify the primary one to be autowired.

• Use @Qualifier when you want to specify a specific bean to be autowired by its name.

• Example: @Primary annotation can be used on a bean definition to mark it as the primary bean to be autowired in case of multiple ...read more