10+ Caspex Corp Senior Java Developer Interview Questions and Answers

Setting up CICD pipeline for Spring Boot microservices using Jenkins/GitLab

• Configure Jenkins/GitLab to listen for changes in the repository

• Set up build steps to compile the code, run unit tests, and perform integration tests

• Use Docker for containerization and Kubernetes for container orchestration

• Deploy artifacts to Artifactory and promote to production environment

• Automate the entire process with appropriate triggers and notifications

Choose AWS for flexibility and customization, choose Dynamo DB for simplicity and scalability

• Consider AWS if you need more flexibility and customization in your data storage solution

• Choose Dynamo DB if you prioritize simplicity and scalability for your mission critical application

• AWS offers a wide range of services and configurations for high availability and scalability, while Dynamo DB is a fully managed NoSQL database service that can automatically scale based on demand

• If ...read more

I would assess the legacy system's data exchange formats and communication protocols, then design a seamless integration plan.

• Analyze the data exchange formats used by the legacy system and determine compatibility with Java application

• Identify the communication protocols utilized by the legacy system and ensure they can be integrated with Java

• Design a middleware layer or API to facilitate communication between the legacy system and Java application

• Implement data mapping and t...read more

Designing a concurrency model for a high calling java application to ensure thread safety and maximize throughput while minimizing deadlock risks.

• Use a combination of thread pools and executor services to manage concurrent requests efficiently.

• Implement synchronization mechanisms such as locks, semaphores, or atomic variables to ensure thread safety.

• Utilize non-blocking algorithms and data structures to reduce contention and avoid deadlocks.

• Consider using asynchronous program...read more

Implement secure authentication and authorization using Auth or JWT token to prevent security vulnerabilities.

• Use HTTPS to encrypt communication between client and server to prevent eavesdropping.

• Implement strong password policies and use password hashing to securely store user credentials.

• Use JWT tokens with short expiration times and refresh tokens to prevent token theft.

• Implement role-based access control to ensure users only have access to authorized resources.

• Regularly u...read more

Design a reliable messaging system using Kafka and RabbitMQ for communication between distributed components.

• Use Kafka for high-throughput, low-latency messaging with strong durability guarantees.

• Implement RabbitMQ for reliable message queuing and delivery.

• Integrate Kafka for real-time event streaming and RabbitMQ for asynchronous communication.

• Leverage Kafka Connect to easily connect Kafka with external systems and RabbitMQ plugins for enhanced functionality.

Implementing circuit breaker pattern in Spring Boot to handle failures in a distributed environment

• Use Spring Boot's resilience4j library to implement the circuit breaker pattern

• Configure the circuit breaker to monitor the external service dependency and trip open when failures exceed a certain threshold

• Handle the circuit breaker state transitions (OPEN, HALF_OPEN, CLOSED) appropriately in your code

• Implement fallback mechanisms to gracefully handle failures when the circuit b...read more

Meta space is a memory space in Java 8 and later versions that replaces PermGen for storing class metadata.

• Meta space is a part of the native memory and is used to store class metadata, such as class structures and method information.

• Unlike PermGen, meta space is not part of the Java heap and is not subject to the same memory limits.

• Meta space automatically resizes based on the application's demand, unlike PermGen which had a fixed size.

• Meta space can be monitored and tuned u...read more

Amazon S3 provides high availability and low latency through data replication and global edge locations.

• Amazon S3 replicates data across multiple availability zones within a region to ensure high availability.

• Global edge locations cache frequently accessed data closer to users, reducing latency.

• Amazon S3 uses a content delivery network (CDN) to deliver content quickly to users worldwide.

Stopping an EC2 instance puts it into a stopped state, while terminating an EC2 instance permanently deletes it.

• Stopping an EC2 instance preserves the data on the instance's EBS volumes

• Terminating an EC2 instance deletes the instance and all associated data

• Stopped instances can be started again, while terminated instances cannot be recovered

• Stopping an instance does not incur charges, but terminating an instance does

Yes, we can override or replace the embedded tomcat server in Spring Boot.

• You can override the embedded Tomcat server by excluding the Tomcat dependency in the pom.xml file and adding a different embedded server dependency like Jetty or Undertow.

• You can also customize the embedded server configuration by creating a bean of type EmbeddedServletContainerCustomizer in a @Configuration class.

• For example, to replace Tomcat with Jetty, exclude the Tomcat dependency and add the Jett...read more

Recovery Time Objective (RTO) and Recovery Point Objective (RPO) are key metrics in disaster recovery planning in AWS.

• RTO is the maximum acceptable downtime for restoring services after a disaster.

• RPO is the maximum acceptable data loss in case of a disaster.

• RTO and RPO help in determining the appropriate backup and recovery strategies.

• For example, if RTO is 4 hours and RPO is 1 hour, it means services should be restored within 4 hours with a maximum data loss of 1 hour.

Analyzing database schema and query execution to identify performance issues

• Review database schema for normalization and indexing

• Analyze query execution plans for inefficiencies

• Consider optimizing data access patterns and query structure

• Use database profiling tools to identify bottlenecks

• Implement caching mechanisms for frequently accessed data

Enable debugging log in Spring Boot application

• Add 'logging.level.root=DEBUG' in application.properties file

• Use '@Slf4j' annotation in the Java class to enable logging

• Set 'logging.level.org.springframework=DEBUG' for Spring framework debugging

Monolithic SOE is a single large application while Microservices architecture breaks down the application into smaller, independent services.

• Monolithic SOE is a single, self-contained application where all components are tightly coupled.

• Microservices architecture breaks down the application into smaller, independent services that communicate through APIs.

• Monolithic SOE is easier to develop and test but can be harder to scale and maintain.

• Microservices architecture allows for ...read more

Method referencing is a way to refer to methods without invoking them directly.

• Used to simplify lambda expressions in Java

• Commonly used in functional interfaces

• Types of method referencing include static, instance, and constructor referencing

Default methods in Java 8 allow interfaces to have method implementations.

• Default methods were introduced in Java 8 to allow interfaces to have method implementations.

• Default methods are used to provide a default implementation for a method in an interface.

• Default methods are useful when adding new methods to existing interfaces without breaking the classes that already use them.

• Default methods can be overridden by classes that implement the interface if needed.

• An example of ...read more

Request mapping is a general annotation used for mapping web requests to handler methods, while Get mapping is a specific type of request mapping used for mapping HTTP GET requests.

• Request mapping is a more general annotation that can be used for mapping various types of HTTP requests, while Get mapping specifically maps HTTP GET requests.

• Get mapping is a shortcut for @RequestMapping(method = RequestMethod.GET), making it easier to specify that a method should handle GET requ...read more