Spring Boot Backend Development: Build Production-Ready REST

Explore Java fundamentals essential for Spring Boot backend development, covering if-else decisions, for and while loops, try-catch error handling, and core concepts like classes, constructors, interfaces, and inheritance.

Create your first Java project in IntelliJ, choose the Java Maven setup, name the demo, select a JDK, and configure a main class for running from anywhere, including pom.xml.

Explore variables and primitive types in Java, including int, float, double, and long, with declaration, assignment, division, modulo, and printing via System.out.println.

Learn how Java handles arrays of integers and characters, and how strings relate to char arrays, with zero-based indexing, access, and in-place updates for multiple values.

Explore how Java uses conditional statements to make decisions, covering if, else, and switch. Learn to use operators, comparisons, and the break and default cases to control program flow.

Explore the concept of functions in Java, including inputs, outputs, return values, and void, with examples of adding numbers and printing results to distinguish function output from terminal output.

Explore how a class acts as a blueprint that combines data and methods to model objects, using constructors, private fields, and getters and setters to ensure safe, controlled access.

Contrast primitive int with wrapper Integer, explaining null values and object methods like toString; explain static members belong to the class, not objects, with practical examples.

Explore strings as objects with built-in methods and use equals for comparison. Then examine enums, lists, and maps with ArrayList and HashMap, including add, get, and put operations.

Explore Java loops—while, for, and for-each—learning when to repeat actions, how to prevent infinite loops, and how to iterate over lists and arrays with index-aware and element-based approaches.

Learn to control for loops with break, continue, and return: exit the loop early, skip a single iteration, or exit the method and return a value.

Explore how inheritance and interfaces shape reusable, flexible code in Java, with extends, super, override, implements, and polymorphism, and see how Spring Boot uses interfaces for repositories, services, and controllers.

Master Java exception handling with try, catch, and throw to prevent crashes, catch specific errors like arithmetic and array index out of bounds, and design custom exceptions for clearer rules.

Explore JSON fundamentals, including key-value pairs, arrays, and nested objects, and how REST APIs and Spring Boot serialize and deserialize data to and from JSON.

Explore how JSON validators ensure correctness and JSON formatters improve readability for Spring Boot REST APIs. Separate validators and formatters to speed debugging and reduce errors.

Map a JSON structure to Java objects by creating a class for each JSON object and a list for each array, including address and skills.

Speed up web app development with a starter project generated by the Spring Initializer, using Maven and Java to run on port 8080.

Create a Spring Boot project in IntelliJ Premium by selecting Spring Boot, Maven, and Spring Web, configuring the Java version, and reloading Maven to run on port 8080.

Implement your first Spring Boot REST endpoint by creating a hello world API with a HelloController annotated as RestController, using GetMapping for /hello, served at localhost:8080.

Build REST endpoints with Spring Boot by returning strings, numbers, and JSON objects like name, age, person, and people; see automatic Java object to JSON conversion.

Discover how to test Spring Boot REST APIs with Postman, including POST, PUT, and DELETE requests, view responses in JSON, status codes, and organize tests with collections.

Explore how Spring Boot applies model-view-controller architecture to organize data, presentation, and logic by separating model, view, and controller, with json responses and the service for real business logic.

Implement create, read, update, and delete operations in a Spring Boot REST API by wiring a service to a controller, using in-memory data, and handling path variables and request bodies.

Implement robust error handling in Spring Boot REST APIs by introducing custom exceptions and a global exception handler, returning clear 404, 400, and 500 responses with ResponseEntity.

Learn how HTTP status codes power REST APIs, from 200, 201, 204 to 400, 401, 403, 404, 500, and 503, with structured JSON error responses.

Explore how Swagger, the OpenAPI-based tool, automatically generates live documentation with an interactive UI, and supports try-it-out of endpoints in Spring Boot via a single dependency.

Store data permanently with databases and use SQL to manage relational data in tables, rows, and columns, while applying primary and foreign keys to relate users and orders.

Set up a cloud postgres database with Superbase, connect it to IntelliJ, and create a users table with id, name, and age to verify the connection.

Learn to create, insert, read, update, and delete data in a database using SQL, including creating tables, defining primary keys, and filtering with where clauses.

Dive deeper into sql queries by using like with wildcards to filter emails, apply order by and limit, and explore aggregate counts alongside and/or conditions on the users table.

Explore how primary keys and foreign keys connect users and orders, define one-to-one, one-to-many, and many-to-many relationships with a bridge table, and how Spring Boot with JPA manages these joins.

Learn how Spring Boot with JPA and Hibernate maps Java classes to database tables, defines an entity with an auto-generated ID, and uses a repository for CRUD operations without SQL.

Connect your Spring Boot app to a PostgreSQL database by wiring application.properties with spring.datasource settings and profiles for dev and production, then verify the connection.

Move from in-memory data to a database with a repository layer and Spring Data JPA, enabling CRUD for user entities and using findByName and existsByEmail as derived queries.

Learn to craft custom queries in Spring Data JPA using JPQL and native SQL, with positional and named parameters, and support modifying updates and deletes.

Leverage DTOs and a model mapper to convert between user entities and user DTOs, exposing only needed data and preventing database structure leakage in a production REST API.

Explore entity relationships in JPA and Hibernate, including one-to-one, one-to-many, many-to-one, and many-to-many, with join columns, join tables, foreign keys, cascade, and lazy loading.

Discover how IntelliJ Ultimate auto-generates JPA entities from your database, mapping tables to code with fields, getters, setters, and ID generation, and navigate relationships and in-code queries.

Examine why a many-to-many relation fails for orders and products and how an order item join entity with quantity fixes it, using Spring Boot and @Transactional for updates and rollback.

Build a real monolithic Spring Boot task manager from scratch with create, read, update, and delete REST endpoints, backed by a task entity, repository, service, and controller layers.

Initialize a Spring Boot backend from Spring Initializr, configure a Maven Java project with Spring Web and Spring Data JPA. Structure code into controller, service, repositories, model, dto, and exceptions.

Create and connect PostgreSQL database for a Spring Boot app, define a tasks table, map it to a Java task entity, and use a task DTO to shape API responses.

Build a production-ready rest api for tasks by wiring repository, service, and controller layers, implementing create, read, update, delete with dto mapping via model mapper and postman testing.

Explore Java streams as a declarative, readable pipeline for filtering, transforming into DTOs, and collecting results, reducing boilerplate and aligning with lambda-driven, functional style in backend data processing.

Master Java lambdas and streams by transforming, sorting, and filtering data with map and flatMap, converting entities to DTOs, flattening nested lists, and removing duplicates with distinct.

Learn how to filter streams in modern java, using map, filter, and toList, and leverage anyMatch, allMatch, and noneMatch to evaluate conditions efficiently.

Learn how streams transform and filter data, forming a pipeline that collects results or acts on each element. Compare toList, collectors.toList, toArray, and foreach with method references to simplify operations.

Learn to retrieve a single stream element with findFirst and findAny, and use Optional to avoid nulls. Use ifPresent and orElse for safe, cleaner handling.

Learn how orElseThrow implements fail-fast behavior with Optionals in Spring Boot, replacing nulls with explicit exceptions when values are missing, ensuring safety and clarity.

Learn advanced Spring Boot utilities to build cleaner, production-ready apps by mastering dependency injection, JSON mapping and validation in REST, the builder pattern, and Lombok to reduce boilerplate.

Discover how Spring beans are created and managed by the application context, and how dependency injection wires components, services, repositories, and controllers via annotations.

Spring Boot uses Jackson's ObjectMapper bean to seamlessly map JSON to Java objects and back in rest APIs, with validation via @Valid and @NotBlank/@Email and customizable error responses.

Explore how Spring injects dependencies using constructor and field injection, with @Autowired, @Qualifier, and @Primary to resolve multiple beans, and @Value from application.properties.

Reduce boilerplate in Java by using Lombok to auto-generate getters, setters, and constructors, and enable annotation processing in your IDE for Spring Boot projects.

Explore how the builder pattern simplifies constructing complex objects in Spring Boot, using Lombok's @Builder to create readable, immutable DTOs and test data, with guidance on when to use it.

Improve a spring boot backend by adding a task status enum, persisting it as a string, and applying validation to create and update inputs with Spring Boot Starter Validation.

Refactor a Spring Boot microservice to cleaner, more maintainable code by adding Lombok, constructors, DTO and entity tuning, using a model mapper, and replacing loops with streams while validating behavior.

Enable uploading a json file, read and convert its content to a list of TaskDTOs with ObjectMapper, validate results, and expose a post upload endpoint.