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Java Back-End Development:
Live Training with Hands-On Exercises

Instructor-Led Live Training | Practical Oriented Hands-On-Exercises | Learn By Doing. 
Beginner + Intermediate Level

This Instructor-led live online training program is designed to provide participants with a comprehensive understanding of Java Back-End Development covering Core Java + Microservices with Spring Boot & Spring Cloud. Building Cloud Native Microservices with Spring Cloud from scratch through Learn-By Doing.

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Downloads

Java SE 17 Download
Spring Tools 4 for Eclipse Download
Postman Download

Creating a Cluster in MongoDB

Learn Spring

Accessing API Documentation using Swagger: (Ex: http://localhost:8081/swagger-ui/index.html)
Accessing H2 DB Console: (Ex: http://localhost:8081/h2-console)

Core Java Programming

Spring Framework Essentials

Building simple Shopping Cart Application with Spring Framework's Dependency Injection (DI) Container, Application Context, Java Configuration, Annotation-based Configuration with Component Scanning


Spring Framework's Dependency Injection (DI) Container: The Dependency Injection (DI) Container is the heart of the Spring Framework and plays a pivotal role in a Spring REST API project. DI promotes loose coupling between components by managing their dependencies. In this context, when designing RESTful services, various components such as controllers, services, repositories, and data sources can be created as Spring beans. The DI Container is responsible for instantiating and managing these beans, as well as resolving their dependencies. This allows developers to inject dependencies into classes, promoting the Inversion of Control (IoC) principle. For instance, you can inject a service into a controller to handle business logic, or inject a repository into a service to interact with the database, all without tight coupling or direct instantiation, enhancing the modularity and testability of your API.
 

Application Context: The Application Context is an integral part of any Spring application, including a Spring REST API project. It serves as a container for all the beans and provides a centralized configuration mechanism. In this context, the Application Context contains configurations for REST controllers, database connections, security, and other components. By initializing the Application Context, your API gains access to these configured beans and can seamlessly use them throughout the application's lifecycle. Moreover, it enables resource management, internationalization, and the ability to apply aspects such as security and transactions.
 

Java Configuration: Java Configuration is an alternative to XML-based configuration in Spring. In a REST API project, you can use Java Configuration classes to define your beans, their dependencies, and the configuration settings. This approach offers several advantages, such as compile-time safety, code readability, and the ability to leverage Java's object-oriented features. Developers can create Java-based configurations for various aspects of the application, such as database connections using @Configuration and @Bean annotations. These configuration classes are typically scanned and loaded by the Spring context during application startup.
 

Annotation-based Configuration with Component Scanning: Annotation-based configuration is a powerful feature of Spring that simplifies the configuration process, especially in a REST API project. Component Scanning, enabled by annotations like @Component, @Service, @Repository, and @Controller, allows Spring to automatically discover and register beans in the Application Context. This simplifies bean management, reduces boilerplate XML or Java Configuration code, and promotes cleaner code organization. For instance, a REST controller can be annotated with @RestController, and Spring will automatically detect and configure it, making it accessible via HTTP endpoints. Component scanning, combined with annotations, simplifies the development of RESTful APIs and promotes best practices like separation of concerns.

Spring Boot

Building Data-Driven Product Mangement REST API: Diving Deep into Spring Data JPA, Hibernate(@One-To-Many, @Many-To-One) ORM, JPQL, MVC, (Service, DAO & Repository) Patterns, DTO, H2, Handling Exceptions, springdoc-openapi, Project Lombok, Spring Security:OAuth2.0

Spring Data JPA repositories with Spring Boot's auto-configuration & Hibernate: Spring Data JPA is a powerful abstraction layer built on top of JPA (Java Persistence API). It simplifies database access by providing high-level, repository-style data access. In a Spring Boot REST API project, Spring Data JPA allows you to define data models (entities) and repositories, which are interfaces that provide methods for querying and manipulating the data. Spring Boot simplifies the setup and configuration of Spring Data JPA repositories by providing auto-configuration capabilities. Spring Data JPA allows you to work with relational databases using high-level abstractions, and Spring Boot takes care of setting up the data source, transaction management, and entity scanning automatically. By creating JPA repositories and extending them with Spring Data interfaces, developers can easily perform CRUD (Create, Read, Update, Delete) operations on database entities. Spring Boot's auto-configuration identifies the data source, configures Hibernate (or other JPA providers), and sets up transaction management, minimizing boilerplate code and making it seamless to integrate JPA into your REST API project.

Hibernate, as the underlying JPA implementation, maps Java objects to database tables and provides mechanisms for defining relationships and executing database queries.

Project Lombok: Project Lombok is a popular library used to reduce boilerplate code in Java applications, including Spring Boot REST APIs. Lombok provides annotations like @Data, @Getter, @Setter, and @NoArgsConstructor that automatically generate getter and setter methods, constructors, and other repetitive code. In a REST API project, Lombok helps keep your codebase concise and readable by eliminating the need for manually writing mundane code. For example, you can annotate your entity classes with @Data to automatically generate getter, setter, equals, and hashCode methods, simplifying the creation of data models.

springdoc-openapi: springdoc-openapi is a library that simplifies the generation of OpenAPI documentation (formerly known as Swagger) for your REST API endpoints. With springdoc-openapi, you can annotate your REST controllers and DTOs (Data Transfer Objects) with OpenAPI annotations to describe the API operations, request/response models, and documentation details. Spring Boot integrates seamlessly with springdoc-openapi, making it easy to generate accurate and interactive API documentation. This documentation is crucial for both developers who are building the API and consumers who need to understand how to interact with it. springdoc-openapi's auto-generation of the API documentation ensures that your REST API is well-documented and user-friendly.

Hibernate ORM: Hibernate is a popular and widely-used implementation of JPA, and Spring Boot seamlessly integrates with it. Hibernate ORM maps Java objects (entities) to database tables, provides an easy way to define relationships, and offers a powerful query language called HQL (Hibernate Query Language). Developers can leverage Hibernate's capabilities to interact with the database in a more object-oriented manner.

JPQL (Java Persistence Query Language): JPQL is a query language for Java Persistence API, and it's particularly useful when working with Spring Data JPA and Hibernate. In a Spring Boot REST API project, you can use JPQL to write database queries in an object-oriented way, directly referencing entity classes and their properties. This helps in creating efficient and database-agnostic queries for retrieving and manipulating data.

MVC (Model-View-Controller) Architecture: Spring Boot encourages the use of the MVC architectural pattern for building RESTful APIs. In this pattern, the Model represents the data and business logic, the View handles the presentation, and the Controller manages the HTTP requests and responses. In a REST API context, the Controller is responsible for handling incoming requests, processing them, and returning appropriate responses. Spring Boot simplifies the creation of RESTful controllers using annotations like @RestController and @RequestMapping.


Service, DAO & Repository Layers: In a Spring Boot REST API project, it's common to organize your code into layers to maintain a clean separation of concerns. The Service layer contains the business logic, the DAO (Data Access Object) layer is responsible for interacting with the database, and the Repository layer, often provided by Spring Data JPA, abstracts the data access. Services orchestrate data flow between controllers and DAO/Repository layers, allowing for modularity and better testability.

DTO (Data Transfer Object): DTOs are used to transfer data between layers of your application and between the server and the client in a RESTful API. DTOs typically mirror the structure of your entities but are designed to carry only the necessary data for a particular use case. They help in reducing over-fetching or under-fetching of data and ensure efficient data transmission in API responses.


H2 Database: H2 is a lightweight, in-memory database often used for development and testing purposes. Spring Boot makes it easy to configure and use H2 as your database during development, allowing you to rapidly prototype and test your REST API without the need for a full-scale database setup.


Handling Exceptions: Exception handling is critical in any REST API project. Spring Boot provides various mechanisms for handling exceptions gracefully, such as @ControllerAdvice to handle global exceptions, custom exception classes, and appropriate HTTP status codes in response entities. Proper exception handling ensures that your API communicates error information effectively to clients and maintains a robust and reliable user experience.

Microservices - Spring Boot & Spring Cloud

Spring Eureka Server: Spring Eureka Server is a critical component of the Spring Cloud ecosystem. It serves as a service registry and discovery server, allowing microservices to register themselves and discover other services in a distributed environment. Eureka facilitates load balancing and fault tolerance by maintaining a registry of available services and their instances. This tool is fundamental for building scalable and resilient microservices architectures.

Spring Cloud Gateway: Spring Cloud Gateway is a powerful API gateway that provides routing, filtering, load balancing, and security features for microservices-based applications. Built on Spring WebFlux and Project Reactor, it allows developers to define custom routing rules and apply filters to incoming and outgoing requests. This enables efficient traffic management, security, and routing between different services.

Spring Cloud Config Server: Spring Cloud Config Server is a centralized configuration management tool. It allows developers to externalize configuration properties from their applications and store them in a central repository. This server retrieves configuration files for various microservices, making it easier to manage configuration changes without the need for redeployment. It supports multiple backends like Git, Vault, and more.

Auth Server: The Auth Server, often part of Spring Security, handles authentication and authorization in microservices-based systems. It provides secure access control to resources, ensuring that only authorized users or services can access protected endpoints. OAuth2 and OpenID Connect are commonly used protocols to implement authentication and authorization in such systems.

Spring RestClient: Spring Framework 6.1 M2 introduces the RestClient, a new synchronous HTTP client. It offers an API similar to WebClient, and that uses the message converters, request factories, interceptors, and other underlying components of RestTemplate.

GitHub: GitHub is a widely-used web-based platform for version control and collaborative software development. Developers use it to host and manage their source code repositories, collaborate with others, track issues, and automate various development tasks through GitHub Actions.


Vault: HashiCorp Vault is a tool for managing secrets and sensitive data in a secure manner. It offers features like secret storage, access control, encryption, and dynamic secrets generation. Vault is often used in microservices architectures to manage API keys, passwords, and other sensitive configuration data.

Zipkin: Zipkin is a distributed tracing system that helps developers monitor and troubleshoot microservices-based applications. It collects and correlates trace data from various services, providing insights into request latency and dependencies between services.

Elasticsearch, Logstash, Kibana (ELK Stack): The ELK Stack is a popular set of tools used for log and data analysis. Elasticsearch is a search and analytics engine, Logstash is a log data processing tool, and Kibana is a data visualization and exploration platform. Together, they enable centralized logging, real-time data analysis, and visualization, making it easier to monitor and troubleshoot microservices applications.

Resilience4J: Resilience4J is a fault tolerance library designed to enhance the resilience of microservices. It provides features like circuit breakers, rate limiting, retry mechanisms, and bulkheads to improve system stability and prevent cascading failures in distributed environments.

Kafka: Apache Kafka is a distributed streaming platform that is widely used for building real-time data pipelines and event-driven microservices architectures. It enables high-throughput, fault-tolerant, and scalable data streaming.

RabbitMQ: RabbitMQ is a message broker that facilitates communication between microservices using message queues. It supports various messaging patterns like publish-subscribe and request-reply, making it suitable for asynchronous communication in distributed systems.

Each of these tools and components plays a crucial role in building and maintaining robust and scalable microservices-based applications in the cloud-native ecosystem.

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