Day 99 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot / #JPA / #Hibernate - Understood and implemented the concept of orphanRemoval in JPA mappings - Learned when orphanRemoval gets triggered in @​OneToMany and @​OneToOne relationships - Differentiated orphanRemoval = true vs CascadeType.REMOVE - Studied real-world use cases where child entities should not exist without the parent #Java #Backend #Hibernate #JPA #100DaysOfCode

Day 98 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot / #JPA / #Hibernate - Went deep into cascading in JPA mappings - Understood how operations propagate from parent to child entities - Covered all cascade types: PERSIST, MERGE, REMOVE, REFRESH, DETACH, ALL - Learned how cascade and orphanRemoval affect real-world data integrity #Java #Backend #Hibernate #JPA #100DaysOfCode

Day 97 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot / #SpringDataJPA / #Hibernate - Understood the concept of owning side vs inverse side in entity relationships - Learned how the owning side controls the foreign key and database updates - Worked with One-to-Many / Many-to-One mappings, mappedBy, and @JoinColumn - Explored cascade operations, orphanRemoval, and why parent entities control child lifecycles #Java #Hibernate #SpringDataJPA #Backend #100DaysOfCode

Day 96 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot / #JPA / #Hibernate - Understood the role of EntityManager as the API to interact with the persistence layer - Learned how the PersistenceContext acts as a first-level cache for managed entities - Saw how persist(), find(), and remove() transition entities between Transient -> Persistent -> Removed states - Understood how it serves data from the PersistenceContext #Java #Hibernate #JPA #Backend #100DaysOfCode

Day 95 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot / #Hibernate - Understood the Hibernate entity lifecycle and its core states: Transient, Persistent, Detached, and Removed - Learned how entities move between states using operations like persist, save, merge, delete, and detach - Explored the role of the persistence context and how it manages entity state and synchronization with the database - Clarified what happens to entities during session operations like clear, close, and garbage collection #Java #Hibernate #JPA #Backend #100DaysOfCode

Day 94 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot / #SpringDataJPA - Understood how sorting works at the data access layer - Implemented sorting using method queries and the Sort class - Learned the core concept of pagination and why it matters for APIs - Worked with Pageable to fetch paginated and sorted results efficiently #Java #Backend #SpringBoot #SpringDataJPA #100DaysOfCode

Day 93 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot / #SpringDataJPA Going deeper into derived query methods and method naming conventions Understanding how Spring Data generates queries from repository method names Working with custom JPQL queries using @​Query annotation Comparing JPQL vs native queries and when to use each #Java #Backend #SpringBoot #JPA #100DaysOfCode

Day 92 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot / #SpringDataJPA - Went deep into Spring Data JPA fundamentals - Worked with different Repository interfaces (CrudRepository, PagingAndSortingRepository, JpaRepository) and understood how they build on each other - Covered the key features of Spring Data JPA — reducing boilerplate, auto-implemented CRUD, pagination & sorting, and query abstraction - Got started with the basics of JPQL and how it operates on entities instead of tables 📌 Repository hierarchy & capabilities visualized in the reply 👇 #Java #Spring #Backend #JPA #Hibernate #100DaysOfCode

Day 91 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot / #SpringJPA / #Hibernate - Focused on common Hibernate configurations and how they affect persistence behavior - Worked with entity-level annotations used in real-world JPA mappings - Understood table-level annotations for defining schema, keys, and constraints - Revisited the key features of JPA — entity management, JPQL, transactions, and entity relationships #Java #Backend #Hibernate #JPA #100DaysOfCode

Day 90 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot / #Hibernate - Diving deep into Hibernate ORM mapping - Understood the clear separation between Spring Data JPA, JPA (specification), and Hibernate (implementation) - Learned how Hibernate translates object state changes into SQL and executes them via JDBC - Got a clearer picture of how repositories, entities, ORM, and the database interact end-to-end (Architecture flow diagram in the reply 👇) #Java #Hibernate #JPA #SpringBoot #Backend #100DaysOfCode

Day 89 of #100DaysOfCode (#JavaRevision) ☕ A little detour to #CoreJava today - Understood the concept of Lambda expressions and why they were introduced - Worked with functional interfaces and lambda syntax - Learned how Streams help process collections declaratively - Practiced common stream operations like map, filter, forEach, and collect #Java #Backend #100DaysOfCode

Day 88 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot - Worked on API response transformation - Defined custom response structures using @​ResponseBodyAdvice<Object> - Applied global response handling with @​RestControllerAdvice - Ensured correct HTTP status codes, error messages, and timestamps in API responses #Java #SpringBoot #Backend #100DaysOfCode

Day 87 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot - Worked with exception handling in Spring Boot - Understood exception handling using annotations at controller and global levels - Learnt how to return appropriate HTTP status codes and meaningful error messages - Created custom error response classes for structured API errors - Annotations of the day : @​ExceptionHandler, @​ControllerAdvice #Java #SpringBoot #Backend #100DaysOfCode

Day 86 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot - Worked on input validation in Spring Boot - Understood common validation annotations like @​NotNull, @​NotBlank, @​NotEmpty, and lots of others - Applied validation at the DTO level to protect the service and persistence layers - Handled validation exceptions to return meaningful error responses #Java #Backend #SpringBoot #100DaysOfCode

Day 85 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot - Understood the role of the Service layer in a Spring Boot application - How it acts as a mediator between the presentation and persistence layers - Learned how separation of concerns is maintained between DTOs and Entities using Controllers and Services - Used ModelMapper to handle clean, bi-directional mapping between Entity and DTO objects #Java #SpringBoot #Backend #100DaysOfCode

Day 84 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot - Worked with the persistence layer using Spring Data JPA - Understood how an ORM works behind the scenes - Defined and worked with an Entity class in detail (table mapping, primary key, annotations) - Used Lombok to auto-generate getters, setters, and constructors - Created a JPA Repository and connected it to the Entity - Implemented basic CRUD operations through REST APIs and verified everything end-to-end #Java #Spring #Backend #JPA #Hibernate #100DaysOfCode

Day 83 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot - Worked with DTOs and used them inside controller methods - Learned how the Jackson library auto-maps DTO objects to JSON - Practiced dynamic URL handling using @​PathVariable and @​RequestParam - Implemented POST, DELETE, PATCH operations using @​PostMapping, @​DeleteMapping, and @​PatchMapping - Used Postman to test these different APIs & understanding how @​RequestBody handles incoming JSON data #Java #SpringBoot #Backend #100DaysOfCode

Day 81 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot - Understood the presentation layer in Spring MVC - Went deeper into Controllers and DTO (Data Transfer Object) patterns - Clarified the difference between @​Controller and @​RestController - Worked with different request mappings based on various HTTP methods #Spring #SpringBoot #Java #Backend #100DaysOfCode

Day 79 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot - Understood the difference between DTOs vs Entities, and why DTOs matter in APIs - Understood how a web server works inside Spring Boot (Tomcat, DispatcherServlet, Controller,Response flow) - Studied how DispatcherServlet routes requests: creates HttpServletRequest/Response, selects handler, invokes controller - Looked at the MVC layers and how each part keeps separation of concerns - Learned how HttpMessageConverter handles JSON serialization/deserialization during requests & responses #Spring #SpringBoot #Java #Backend #100DaysOfCode

Day 75 of #100DaysOfCode (#JavaRevision) ☕ #SpringBoot / #Java - Spring Boot web project flow: client → controller → service → repository → database - Worked with controller annotations: @Controller and @RestController - Request mappings: mapping HTTP requests to controller methods - Dynamic URL paths using @PathVariable and @RequestParam #Java #SpringBoot #Backend #100DaysOfCode