Spring + JPA + AWS + Microservice + Docker + Zenkin

**Spring Boot Basic Questions**
🔸 Spring Boot is a framework used to build production-ready applications with minimal configuration  
🔸 It provides auto-configuration, embedded servers like Tomcat or Jetty, and starter dependencies  
🔸 Spring Boot Starter is a collection of pre-configured dependencies for specific features  
🔸 Configuration is handled using application.properties or application.yml  
🔸 Profiles allow different configurations for environments like development, testing, and production  

**Spring Boot Intermediate Concepts**
🔸 Auto-configuration automatically sets up beans based on classpath and properties  
🔸 Embedded servers remove the need for external deployment  
🔸 Actuator provides monitoring features like health checks and metrics  

**Spring Boot Advanced Concepts**
🔸 @RestController returns JSON or XML responses, while @Controller is used for views  
🔸 Spring Security is used for authentication and authorization  
🔸 SpringApplication.run() starts the application and initializes the Spring context  

**JPA Basic Concepts**
🔸 JPA is a specification for managing relational data using ORM  
🔸 Hibernate is an implementation of JPA  
🔸 Common annotations include @Entity, @Id, @GeneratedValue, and @Table  
🔸 EntityManager is used to interact with the persistence context  

**JPA Intermediate Concepts**
🔸 Entity states include transient, persistent, and detached  
🔸 Fetch types include eager and lazy loading  
🔸 JPQL is used to query based on entity models  
🔸 Relationships are defined using annotations like @OneToOne and @OneToMany  

**JPA Advanced Concepts**
🔸 @JoinColumn defines a column, while @JoinTable defines a join table  
🔸 Generation types include AUTO, IDENTITY, SEQUENCE, and TABLE  
🔸 Caching includes first-level and second-level cache  

**Spring Boot with JPA**
🔸 Integration requires adding JPA dependency and configuration properties  
🔸 CrudRepository provides basic operations  
🔸 JpaRepository adds advanced JPA features  
🔸 PagingAndSortingRepository supports pagination  
🔸 @Query is used for custom queries  
🔸 @Transactional manages transactions  

**Microservices Basics**
🔸 Microservices are small independent services forming a system  
🔸 Key features include scalability, resilience, and flexibility  
🔸 Unlike monolithic systems, services are independently deployable  
🔸 APIs enable communication between services  
🔸 Advantages include faster development and fault isolation  

**Microservices Intermediate Concepts**
🔸 Service discovery helps services find each other  
🔸 API Gateway acts as a central entry point  
🔸 Challenges include data consistency and monitoring  
🔸 Circuit breakers prevent cascading failures  
🔸 Transactions are handled using saga patterns or 2PC  

**Microservices Advanced Concepts**
🔸 Communication can be synchronous or asynchronous  
🔸 Eventual consistency ensures data sync over time  
🔸 Docker and Kubernetes help in deployment and scaling  
🔸 Monitoring tools include Prometheus and Grafana  
🔸 Security is implemented using JWT and HTTPS  

**AWS Basics**
🔸 AWS is a cloud platform providing scalable infrastructure  
🔸 Core services include compute, storage, networking, and databases  
🔸 EC2 is used for servers, S3 for storage  
🔸 Availability zones provide high availability  
🔸 Regions are global locations of AWS  

**AWS Intermediate Concepts**
🔸 IAM manages access and permissions  
🔸 ELB distributes traffic across servers  
🔸 CloudFormation enables infrastructure as code  
🔸 Auto Scaling adjusts resources based on demand  
🔸 Data security in S3 includes encryption and policies  

**AWS Advanced Concepts**
🔸 Lambda is a serverless compute service  
🔸 Cost optimization uses reserved and spot instances  
🔸 Shared responsibility model divides security roles  
🔸 SNS and SQS handle messaging  
🔸 CloudWatch monitors resources and CloudTrail tracks activity  
🔸 Elastic Beanstalk simplifies deployment  

**Docker Basics**
🔸 Docker is a containerization platform  
🔸 Components include images, containers, engine, and Docker Hub  
🔸 Image is a blueprint, container is a running instance  
🔸 Dockerfile defines how to build images  

**Docker Intermediate Concepts**
🔸 Docker Compose manages multi-container apps  
🔸 Volumes store persistent data  
🔸 Docker Swarm is simpler, Kubernetes is more advanced  
🔸 Security includes limiting privileges and scanning images  

**Kubernetes Basics**
🔸 Kubernetes manages container deployment and scaling  
🔸 Architecture includes master and worker nodes  
🔸 Pod is the smallest unit of deployment  
🔸 Networking is handled via CNI plugins  

**Kubernetes Intermediate Concepts**
🔸 ReplicaSet ensures running instances  
🔸 Deployment manages updates  
🔸 Service exposes pods  
🔸 ConfigMaps and Secrets manage configuration  
🔸 Scaling can be horizontal or vertical  

**Jenkins Basics**
🔸 Jenkins is a CI/CD tool  
🔸 Features include pipelines and plugins  
🔸 Pipeline automates build and deployment  
🔸 Freestyle projects are simple job configurations  

**Jenkins Intermediate Concepts**
🔸 Security includes RBAC and HTTPS  
🔸 Agents execute tasks  
🔸 Integration is done via plugins  
🔸 Blue Ocean provides modern UI for pipelines