Wednesday, 15 April 2026

Open API documentation

https://learn.openapis.org/introduction.html

Wednesday, 18 March 2026

Design pattern

Let’s simplify everything from Refactoring Guru Design Patterns into very easy (lemon 😄) terms + real-world + Java/Spring examples.

🧠 First: What is a Design Pattern?

👉 A design pattern = proven solution to common coding problem

Think like:

“This problem already happened before → smart people solved it → reuse that solution”

🧩 3 Types of Design Patterns

1. 🏗️ Creational (Object banana ka tareeka)

How objects are created

2. 🧱 Structural (Object ko kaise jode)

How objects are structured/connected

3. 🔄 Behavioral (Object kaise behave kare)

How objects communicate

🏗️ 1. CREATIONAL PATTERNS (Creation)

1. Singleton 🧍

👉 Only one object in whole system

🍋 Lemon Example:

There is only one Aadhaar database

💻 Java Example:

class Config {
    private static Config instance = new Config();
    private Config() {}
    public static Config getInstance() {
        return instance;
    }
}

🔥 Real Use:

DB connection pool
Redis client
Spring Beans (default singleton)

2. Factory 🏭

👉 Object create karne ka decision system lega

🍋 Example:

You order coffee

Latte / Cappuccino / Espresso
System decides what to create

💻 Java Example:

interface Notification {}
class Email implements Notification {}
class SMS implements Notification {}

class Factory {
    public static Notification get(String type) {
        if (type.equals("email")) return new Email();
        return new SMS();
    }
}

🔥 Real Use:

Payment methods
Notification service

3. Builder 🧱

👉 Complex object step-by-step banana

🍋 Example:

Ordering pizza

size
cheese
toppings

💻 Example:

User user = User.builder()
    .name("Pawan")
    .age(30)
    .build();

🔥 Real Use:

DTO creation
Immutable objects

🧱 2. STRUCTURAL PATTERNS

4. Adapter 🔌

👉 Incompatible cheez ko compatible banana

🍋 Example:

Indian charger → US socket adapter

💻 Example:

Old API → New API wrapper

🔥 Real Use:

Third-party API integration (very important for you!)

5. Decorator 🎁

👉 Existing object ko extra feature dena

🍋 Example:

Coffee + milk + chocolate

💻 Example:

class Coffee {}
class MilkDecorator extends Coffee {}

🔥 Real Use:

Logging
Security layers

6. Facade 🏢

👉 Complex system ko simple interface dena

🍋 Example:

Swiggy app → kitchen, delivery, payment sab hide

💻 Example:

class OrderService {
    void placeOrder() {
        payment();
        inventory();
        delivery();
    }
}

🔥 Real Use:

Microservice orchestration

🔄 3. BEHAVIORAL PATTERNS

7. Strategy 🎯

👉 Multiple ways to do same task

🍋 Example:

Travel options:

Car
Bike
Train

💻 Example:

interface PaymentStrategy {
    void pay();
}
class UPI implements PaymentStrategy {}
class Card implements PaymentStrategy {}

🔥 Real Use:

👉 Your AWS SES email system can use this!

8. Observer 👀

👉 One change → multiple systems notified

🍋 Example:

YouTube subscribe → notification

💻 Example:

observer.update();

🔥 Real Use:

SNS, Kafka, Event-driven systems

9. Command 📦

👉 Request ko object bana do

🍋 Example:

Remote control button

💻 Example:

interface Command {
    void execute();
}

🔥 Real Use:

Queue (SQS)
Task execution

🚀 Most Important for YOU (Based on your work)

Since you're working with:

Spring Boot
AWS SES, SQS
Microservices

👉 Focus on:

Strategy → email sending logic
Factory → notification type
Observer → event system (SNS/SQS)
Facade → service layer
Builder → DTO creation

🎯 Simple Memory Trick

Type	Meaning
Creational	Object kaise banega
Structural	Object kaise judega
Behavioral	Object kaise behave karega

💡 Real-world Example (Your Project)

Your Email System:

Factory → choose Email/SMS
Strategy → SES / SMTP
Observer → Bounce/Delivery events
Command → SQS message

Facade → EmailService

Perfect — let’s go deep into Creational Patterns (this is where strong backend engineers stand out in interviews + system design).

I’ll explain:

Core idea (simple 🍋)
When to use (important!)
Internal thinking (how it works)
6+ real-world examples (with Java/Spring mapping)

🏗️ CREATIONAL DESIGN PATTERNS (Deep Dive)

👉 These patterns solve:

“Object kaise banega — simple, controlled, flexible way mein?”

1. 🧍 Singleton Pattern (One instance only)

🍋 Simple Idea:

System mein sirf ek hi object allowed

🧠 Why needed?

Avoid multiple expensive objects
Maintain shared state

⚙️ Internal Concept:

Private constructor
Static instance
Global access method

💻 Production-Ready Java (Thread-safe)

public class ConfigManager {

    private static volatile ConfigManager instance;

    private ConfigManager() {}

    public static ConfigManager getInstance() {
        if (instance == null) {
            synchronized (ConfigManager.class) {
                if (instance == null) {
                    instance = new ConfigManager();
                }
            }
        }
        return instance;
    }
}

🔥 Real-world examples (6+)

1. DB Connection Pool

DataSource ds = DataSourceSingleton.getInstance();

2. Redis Client

Jedis jedis = RedisManager.getInstance().getClient();

3. Logger (Log4j / SLF4J)

👉 Only one logger config

4. Spring Beans (Default)

@Service
class UserService {}

👉 Spring internally uses Singleton

5. Cache Manager

CacheManager.getInstance().put(key, value);

6. Configuration Loader

ConfigManager.getInstance().get("db.url");

⚠️ When NOT to use:

When object needs different states (use prototype)

2. 🏭 Factory Pattern (Object creation decision hidden)

🍋 Simple Idea:

“Tum bas bolo kya chahiye — system bana ke dega”

🧠 Why needed?

Remove new keyword everywhere
Loose coupling

💻 Example (Advanced)

interface Payment {
    void pay();
}

class UPI implements Payment {
    public void pay() { System.out.println("UPI"); }
}

class Card implements Payment {
    public void pay() { System.out.println("Card"); }
}

class PaymentFactory {
    public static Payment getPayment(String type) {
        switch(type) {
            case "UPI": return new UPI();
            case "CARD": return new Card();
            default: throw new IllegalArgumentException();
        }
    }
}

🔥 Real-world examples

1. Payment System

Payment p = PaymentFactory.getPayment("UPI");

2. Notification System

Notification n = NotificationFactory.get("EMAIL");

3. Spring BeanFactory

👉 Spring internally uses Factory

4. AWS SDK Clients

AmazonSQS sqs = AmazonSQSClientBuilder.defaultClient();

5. JDBC DriverManager

Connection con = DriverManager.getConnection(url);

6. Parser System

Parser parser = ParserFactory.get("JSON");

⚠️ Problem solved:

👉 No if-else everywhere

3. 🧱 Builder Pattern (Complex object creation)

🍋 Simple Idea:

“Step-by-step object banana”

🧠 Why needed?

Too many constructor arguments
Optional fields

💻 Example

class User {
    private String name;
    private int age;
    private String email;

    public static class Builder {
        private String name;
        private int age;
        private String email;

        public Builder setName(String name) {
            this.name = name;
            return this;
        }

        public Builder setAge(int age) {
            this.age = age;
            return this;
        }

        public Builder setEmail(String email) {
            this.email = email;
            return this;
        }

        public User build() {
            User u = new User();
            u.name = this.name;
            u.age = this.age;
            u.email = this.email;
            return u;
        }
    }
}

🔥 Real-world examples

1. HTTP Request (Spring)

ResponseEntity.ok().header("x","y").body(data);

2. Lombok Builder

User user = User.builder()
    .name("Pawan")
    .email("p@test.com")
    .build();

3. AWS SES Email

SendEmailRequest request = new SendEmailRequest()
    .withDestination(...)
    .withMessage(...);

4. Kafka Message Builder

ProducerRecord record = new ProducerRecord(topic, key, value);

5. Query Builder (JPA)

criteriaBuilder.createQuery(User.class);

6. Docker Config (Your project!)

👉 step-by-step container config

4. 🧬 Prototype Pattern (Clone object)

🍋 Simple Idea:

“Naya object banane ke bajaye copy karo”

🧠 Why needed?

Object creation expensive hai

💻 Example

class User implements Cloneable {
    String name;

    public Object clone() throws CloneNotSupportedException {
        return super.clone();
    }
}

🔥 Real-world examples

1. Template Email Copy

Email copy = original.clone();

2. Spring Prototype Scope

@Scope("prototype")
@Bean
public User user() { return new User(); }

3. Object Copy in Cache

return cachedObject.clone();

4. Game Development (Characters)

5. Document Templates

6. Request Retry Copy

👉 same request clone

5. 🏢 Abstract Factory (Factory of factories)

🍋 Simple Idea:

“Factory bhi dynamically choose hogi”

🧠 Why needed?

Multiple related object families

💻 Example

interface UIFactory {
    Button createButton();
}

class WindowsFactory implements UIFactory {
    public Button createButton() { return new WindowsButton(); }
}

class MacFactory implements UIFactory {
    public Button createButton() { return new MacButton(); }
}

🔥 Real-world examples

1. Multi-cloud system (AWS/Azure)

CloudFactory factory = getFactory("AWS");
factory.createS3();

2. DB Support (MySQL / Mongo)

DAOFactory factory = getFactory("MYSQL");

3. UI Themes

4. Payment Gateway Providers

GatewayFactory.get("RAZORPAY");

5. Messaging Systems

Factory → Kafka / RabbitMQ

6. Your Microservice Design

👉 Per-tenant implementation

🧠 Interview-Level Insight

Difference:

Pattern	Key Idea
Singleton	One instance
Factory	Object creation logic
Builder	Step-by-step creation
Prototype	Copy object
Abstract Factory	Group of factories

🚀 YOUR PROJECT MAPPING (VERY IMPORTANT)

For your AWS Email System:

Component	Pattern
SES / SMTP switch	Strategy + Factory
Email Request	Builder
Event handling	Observer
Config	Singleton
Multi-provider	Abstract Factory

Perfect, Pawan — let’s design a real production-level Spring Boot microservice using ALL creational patterns together.

I’ll build this around something relevant to your work:
👉 Email Notification Service (AWS SES / SMTP / Future providers)

🚀 🏗️ SYSTEM OVERVIEW

🎯 Goal:

Send emails using different providers dynamically:

AWS SES
SMTP
Future: SendGrid

🧩 WHERE EACH PATTERN FITS

Pattern	Usage
Singleton	Config / AWS clients
Factory	Choose provider
Abstract Factory	Cloud provider family
Builder	Email request creation
Prototype	Retry email copy

📦 HIGH-LEVEL FLOW

Controller → Service → Factory → Provider → Send Email
                         ↓
                    Builder (email)
                         ↓
                  Prototype (retry)

1️⃣ 🧍 Singleton → Config Manager

👉 One config across system

@Component
public class AppConfig {

    private final Map<String, String> config = new HashMap<>();

    public AppConfig() {
        config.put("provider", "SES");
    }

    public String get(String key) {
        return config.get(key);
    }
}

✅ Spring makes it singleton automatically

2️⃣ 🧱 Builder → Email Object

👉 Complex object (to, subject, body, attachments)

public class Email {

    private String to;
    private String subject;
    private String body;

    private Email() {}

    public static class Builder {
        private String to;
        private String subject;
        private String body;

        public Builder to(String to) {
            this.to = to;
            return this;
        }

        public Builder subject(String subject) {
            this.subject = subject;
            return this;
        }

        public Builder body(String body) {
            this.body = body;
            return this;
        }

        public Email build() {
            Email email = new Email();
            email.to = this.to;
            email.subject = this.subject;
            email.body = this.body;
            return email;
        }
    }
}

3️⃣ 🏭 Factory → Provider Selection

public interface EmailProvider {
    void send(Email email);
}

Implementations:

@Component
public class SESProvider implements EmailProvider {
    public void send(Email email) {
        System.out.println("Sending via SES");
    }
}

@Component
public class SMTPProvider implements EmailProvider {
    public void send(Email email) {
        System.out.println("Sending via SMTP");
    }
}

Factory

@Component
public class EmailProviderFactory {

    @Autowired
    private SESProvider ses;

    @Autowired
    private SMTPProvider smtp;

    public EmailProvider getProvider(String type) {
        if ("SES".equalsIgnoreCase(type)) return ses;
        return smtp;
    }
}

4️⃣ 🏢 Abstract Factory → Cloud Providers

👉 Suppose future:

AWS (SES, SQS)
Azure (Email, Queue)

public interface CloudFactory {
    EmailProvider createEmailProvider();
}

AWS Factory

@Component
public class AWSFactory implements CloudFactory {

    @Autowired
    private SESProvider ses;

    public EmailProvider createEmailProvider() {
        return ses;
    }
}

Azure Factory (future)

@Component
public class AzureFactory implements CloudFactory {

    public EmailProvider createEmailProvider() {
        return new SMTPProvider();
    }
}

5️⃣ 🧬 Prototype → Retry Email

👉 Same email clone for retry

public class Email implements Cloneable {

    public Email clone() {
        try {
            return (Email) super.clone();
        } catch (CloneNotSupportedException e) {
            throw new RuntimeException(e);
        }
    }
}

Retry Logic

public void retry(Email email) {
    Email copy = email.clone();
    send(copy);
}

6️⃣ 🎯 SERVICE LAYER (Putting everything together)

@Service
public class EmailService {

    @Autowired
    private AppConfig config;

    @Autowired
    private EmailProviderFactory factory;

    public void sendEmail(String to, String subject, String body) {

        // Builder
        Email email = new Email.Builder()
                .to(to)
                .subject(subject)
                .body(body)
                .build();

        // Factory
        String providerType = config.get("provider");
        EmailProvider provider = factory.getProvider(providerType);

        provider.send(email);
    }
}

7️⃣ 🌐 CONTROLLER

@RestController
@RequestMapping("/email")
public class EmailController {

    @Autowired
    private EmailService service;

    @PostMapping
    public String send() {
        service.sendEmail("test@mail.com", "Hello", "Body");
        return "Sent";
    }
}

🔥 REAL PRODUCTION ENHANCEMENTS (VERY IMPORTANT)

Since you're working on large-scale email system, add:

✅ 1. Strategy (Bonus pattern)

Switch providers dynamically:

Map<String, EmailProvider> providers;

✅ 2. Add SQS (Command pattern)

queue.send(emailRequest);

✅ 3. Observer (SES events)

Bounce
Delivery
Complaint

✅ 4. Rate Limiting

Avoid SES blocking (you faced this already)

✅ 5. Retry with Backoff

retry after 1s → 5s → 10s

🧠 HOW INTERVIEWER WILL TEST YOU

They will ask:

👉 “Design email system supporting multiple providers”

Your answer:

Builder → Email object
Factory → provider selection
Strategy → sending logic
Singleton → config
Prototype → retry

🔥 This is staff-level answer

🚀 NEXT LEVEL (I recommend)

If you want to go even deeper:

👉 I can upgrade this to:

Kafka-based event system
Fully async microservices
Circuit breaker (Resilience4j)
Multi-tenant email system (VERY IMPORTANT FOR YOU)

Just tell me:
👉 “Make it production-level architecture”

Tuesday, 17 February 2026

Spring boot annotation list

✅ 1. Core Spring / IOC & Bean Management

Stereotype annotations

@Component

@Service

@Repository

@Controller

@RestController

Configuration & Beans

@Configuration

@Bean

@Import

@ImportResource

@ComponentScan

@PropertySource

@Profile

@Scope

@Lazy

@DependsOn

@Primary

@Qualifier

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 1/2417/02/2026, 16:47 Spring Boot Annotations List

Dependency Injection

@Autowired

@Value

@Required

✅ 2. Spring Boot Specific

@SpringBootApplication

@EnableAutoConfiguration

@ConfigurationProperties

@EnableConfigurationProperties

@SpringBootTest

@TestConfiguration

@MockBean

@SpyBean

✅ 3. Web / MVC / REST

Controller & Mapping

@RequestMapping

@GetMapping

@PostMapping

@PutMapping

@DeleteMapping

@PatchMapping

Request handling

@RequestParam

@PathVariable

@RequestBody

@ResponseBody

@ResponseStatus

@RequestHeader

@CookieValue

@ModelAttribute

@MatrixVariable

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 2/2417/02/2026, 16:47 Exception Handling

@ExceptionHandler

@ControllerAdvice

@RestControllerAdvice

Spring Boot Annotations List

@CrossOrigin

✅ 4. Validation (JSR-303 / Hibernate Validator)

@Valid

@Validated

@NotNull

@NotEmpty

@NotBlank

@Size

@Min

@Max

@Positive

@Negative

@Email

@Pattern

@Future

@Past

@Digits

@AssertTrue

@AssertFalse

✅ 5. Spring Data JPA / Persistence

Repository

@Repository

@EnableJpaRepositories

Entity mapping (JPA)

@Entity

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 3/2417/02/2026, 16:47 Spring Boot Annotations List

@Table

@Id

@GeneratedValue

@Column

@Transient

@Lob

@Enumerated

@Temporal

Relations

@OneToOne

@OneToMany

@ManyToOne

@ManyToMany

@JoinColumn

@JoinTable

@MapsId

@Embedded

@Embeddable

Query

@Query

@NamedQuery

@Modifying

@Param

@Procedure

Transactions

@Transactional

✅ 6. Security (Spring Security)

@EnableWebSecurity

@EnableMethodSecurity

@Secured

@RolesAllowed

@PreAuthorize

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 4/2417/02/2026, 16:47 Spring Boot Annotations List

@PostAuthorize

@PreFilter

@PostFilter

@AuthenticationPrincipal

✅ 7. Scheduling & Async

@EnableScheduling

@Scheduled

@EnableAsync

@Async

✅ 8. Caching

@EnableCaching

@Cacheable

@CachePut

@CacheEvict

@Caching

✅ 9. Spring Cloud / Microservices (very common)

@EnableDiscoveryClient

@FeignClient

@EnableFeignClients

@LoadBalanced

@CircuitBreaker

@Retryable

@Recover

@RefreshScope

✅ 10. Messaging (Kafka / JMS / RabbitMQ)

@EnableKafka

@KafkaListener

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 5/2417/02/2026, 16:47 Spring Boot Annotations List

@SendTo

@EnableJms

@JmsListener

@RabbitListener

@RabbitHandler

✅ 11. Testing

@RunWith

@ExtendWith

@WebMvcTest

@DataJpaTest

@JdbcTest

@JsonTest

@RestClientTest

@AutoConfigureMockMvc

@AutoConfigureTestDatabase

@TestPropertySource

@ActiveProfiles

@DirtiesContext

@BeforeEach

@AfterEach

@BeforeAll

@AfterAll

@Test

✅ 12. AOP (Aspect Oriented Programming)

@Aspect

@Before

@After

@AfterReturning

@AfterThrowing

@Around

@Pointcut

@EnableAspectJAutoProxy

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 6/2417/02/2026, 16:47 Spring Boot Annotations List

✅ 13. Internationalization / Formatting

@DateTimeFormat

@NumberFormat

✅ 14. Conditional Annotations (Auto-Config magic)

@Conditional

@ConditionalOnBean

@ConditionalOnMissingBean

@ConditionalOnProperty

@ConditionalOnClass

@ConditionalOnMissingClass

@ConditionalOnWebApplication

@ConditionalOnNotWebApplication

@ConditionalOnExpression

✅ 15. Actuator

@Endpoint

@ReadOperation

@WriteOperation

@DeleteOperation

⚠

Reality Check

There is NO single official list called “all Spring Boot annotations” because:

Spring = Core + Web + Data + Security + Cloud + Test + Integration

JPA & Validation annotations come from Java EE / Jakarta

New annotations added every

version

If you really want absolute every annotation, you must scan packages:

org.springframework.*

jakarta.persistence.*

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 7/2417/02/2026, 16:47 jakarta.validation.*

org.springframework.boot.*

Spring Boot Annotations List

🎯 What I recommend for you (as a senior dev)

Master these 30 first:

less

Copy code

@SpringBootApplication

@Component

@Service

@Repository

@RestController

@Autowired

@Configuration

@Bean

@RequestMapping

@GetMapping

@PostMapping

@RequestBody

@PathVariable

@Transactional

@Entity

@Id

@OneToMany

@ManyToOne

@JoinColumn

@Query

@ExceptionHandler

@ControllerAdvice

@Scheduled

@Async

@Cacheable

@PreAuthorize

@FeignClient

@Test

@SpringBootTest

If you

want, next I can give you one of these (your choice):

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 8/2417/02/2026, 16:47 A) 📄 B) 🧠 C) 🔥 D)

Spring Boot Annotations List

PDF cheat sheet of all annotations category-wise

Diagram of Spring annotation layers

Interview-focused annotation list (top 50)

🧪

Example project showing 30 annotations used

E) Full table (Annotation | Purpose | Example)

Just reply with: A / B / C / D / E 😄

A and E

Awesome choice, Pawan 😎

Here is:

wise)

✅ A) Spring Boot Annotations – Cheat Sheet (Category-

and

✅ E) Full Table (Annotation | Purpose | Example)

You can copy this and I can convert it into a PDF for you next if you say:

👉 “Convert this into PDF”

Copy code

🅐 Spring Boot Annotation Cheat Sheet 📄

🔹 Core & IOC

less

@Component, @Service, @Repository, @Controller, @RestController

@Configuration, @Bean, @ComponentScan

@Autowired, @Qualifier, @Primary

@Value, @PropertySource

@Profile, @Scope, @Lazy, @DependsOn

🔹 Spring Boot

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 9/2417/02/2026, 16:47 less

Spring Boot Annotations List

Copy code

@SpringBootApplication

@EnableAutoConfiguration

@ConfigurationProperties

@EnableConfigurationProperties

@SpringBootTest

@TestConfiguration

@MockBean, @SpyBean

🔹 Web / REST

less

@RequestMapping

@GetMapping, @PostMapping, @PutMapping, @DeleteMapping, @PatchMapping

Copy code

@RequestParam, @PathVariable

@RequestBody, @ResponseBody

@ResponseStatus

@RequestHeader, @CookieValue

@ModelAttribute

@CrossOrigin

🔹 Exception Handling

less

@ExceptionHandler

@ControllerAdvice

@RestControllerAdvice

Copy code

🔹 Validation

less

Copy code

@Valid, @Validated

@NotNull, @NotEmpty, @NotBlank

@Size, @Min, @Max

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 10/2417/02/2026, 16:47 @Email, @Pattern

@Positive, @Negative

@Future, @Past

@Digits

Spring Boot Annotations List

🔹 JPA / Hibernate

less

@Entity, @Table

@Id, @GeneratedValue

@Column, @Transient, @Lob

@OneToOne, @OneToMany, @ManyToOne, @ManyToMany

@JoinColumn, @JoinTable

@Embedded, @Embeddable

@Enumerated, @Temporal

Copy code

🔹 Spring Data

less

@Repository

@EnableJpaRepositories

@Query

@Modifying

@Param

@Transactional

Copy code

🔹 Security

less

@EnableWebSecurity

@EnableMethodSecurity

@PreAuthorize

@PostAuthorize

@Secured

Copy code

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 11/2417/02/2026, 16:47 @RolesAllowed

@AuthenticationPrincipal

Spring Boot Annotations List

🔹 Scheduling & Async

less

Copy code

@EnableScheduling

@Scheduled

@EnableAsync

@Async

🔹 Cache

less

Copy code

@EnableCaching

@Cacheable

@CachePut

@CacheEvict

@Caching

🔹 Messaging

less

Copy code

@KafkaListener

@EnableKafka

@JmsListener

@EnableJms

@RabbitListener

@RabbitHandler

🔹 Spring Cloud

less

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 12/2417/02/2026, 16:47 Spring Boot Annotations List

Copy code

@EnableDiscoveryClient

@FeignClient

@EnableFeignClients

@LoadBalanced

@RefreshScope

@Retryable

@Recover

🔹 AOP

less

@Aspect

@Before

@After

@AfterReturning

@AfterThrowing

@Around

@Pointcut

@EnableAspectJAutoProxy

Copy code

🔹 Testing

less

@RunWith / @ExtendWith

@Test

@SpringBootTest

@WebMvcTest

@DataJpaTest

@MockBean

@AutoConfigureMockMvc

@TestPropertySource

@ActiveProfiles

@DirtiesContext

@BeforeEach, @AfterEach

Copy code

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 13/2417/02/2026, 16:47 🔹 Actuator

less

Spring Boot Annotations List

@Endpoint

@ReadOperation

@WriteOperation

@DeleteOperation

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🅔 Full Table: Annotation | Purpose | Example

Annotation Purpose Example

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@SpringBootApplicatio

Main entry point @SpringBootApplication public

class App {}

@Component Generic bean @Component class MyBean {}

@Service Business logic layer @Service class UserService {}

@Repository DAO layer @Repository interface UserRepo

{}

@RestControllerREST controller @RestController class

UserController {}

@Autowired Inject dependency @Autowired UserService service;

@Bean Create bean manually @Bean DataSource ds()

@Configuration Config class @Configuration class AppConfig

{}

@GetMapping HTTP GET @GetMapping("/users")

@PostMapping HTTP POST @PostMapping("/users")

@RequestBodyMap JSON to object public save(@RequestBody User u)

@PathVariable U

L variable @PathVariable int id

@RequestParam Query param @RequestParam String name

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Annotation Purpose Example

@ResponseStatus Custom HTTP status @ResponseStatus(HttpStatus.OK)

@ExceptionHandler Handle exception @ExceptionHandler(Exception.clas

@ControllerAdvice Global exception

handler

@ControllerAdvice class GlobalEx

{}

@Entity JPA entity @Entity class User {}

@Id Primary key @Id Long id;

@GeneratedValue Auto PK @GeneratedValue(strategy=AUTO)

@OneToManyRelationship @OneToMany List<Order>

@ManyToOneRelationship @ManyToOne User user

@JoinColumn FK column @JoinColumn(name="user_id")

@Query Custom query @Query("select u from User u")

@Transactional Transaction mgmt @Transactional public void

save()

@Valid Trigger validation public save(@Valid User u)

@NotNull Field validation @NotNull String name;

@EnableScheduling Enable scheduler @EnableScheduling

@Scheduled Cron job @Scheduled(cron="0 0 * * *")

@EnableAsync Enable async @EnableAsync

@AsyncR

un async @Async public void task()

@Cacheable Cache result @Cacheable("users")

@PreAuthorize Security rule @PreAuthorize("hasRole('ADMIN')"

)

@FeignClientREST client @FeignClient("order-service")

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Annotation Purpose Example

@Aspect AOP class @Aspect class LogAspect {}

@Before Before advice @Before("execution(*)")

@Test Unit test @Test void testSave()

@SpringBootTest Full context test @SpringBootTest class TestApp {}

@MockBeanMock bean @MockBean UserService service;

@Endpoint Actuator endpoint @Endpoint(id="custom")

🎁 Next Step (Free Bonus)

I can generate for you:

✅ PDF Cheat Sheet

✅ Excel table (Annotation | Purpose | Example)

✅ Printable A4 sheet

✅ Mind map diagram

Just reply one word:

PDF or EXCEL or DIAGRAM or ALL

And I’ll generate it for you 🚀

category-wise give me annotation list

Got it 👍 You

want a pure category-wise list of Spring Boot / Spring annotations (no

explanations, no examples — just clean grouped lists).

Here is the most complete practical catalog used in real Spring Boot applications.

🟢 1. Core / IOC / Bean Management

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 16/2417/02/2026, 16:47 Spring Boot Annotations List

@Component

@Service

@Repository

@Controller

@RestController

@Configuration

@Bean

@ComponentScan

@Import

@ImportResource

@DependsOn

@Lazy

@Scope

@Primary

@Qualifier

@Profile

@PropertySource

@Value

@Autowired

@Required

@Lookup

🟢 2. Spring Boot Specific

@SpringBootApplication

@EnableAutoConfiguration

@AutoConfiguration

@ConfigurationProperties

@EnableConfigurationProperties

@ConstructorBinding

@SpringBootConfiguration

@TestConfiguration

@SpringBootTest

@MockBean

@SpyBean

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 17/2417/02/2026, 16:47 Spring Boot Annotations List

🟢 3. Web / MVC / REST

Mapping

@RequestMapping

@GetMapping

@PostMapping

@PutMapping

@DeleteMapping

@PatchMapping

Request / Response

@RequestParam

@PathVariable

@RequestBody

@ResponseBody

@ResponseStatus

@RequestHeader

@CookieValue

@ModelAttribute

@MatrixVariable

@CrossOrigin

Exception

@ExceptionHandler

@ControllerAdvice

@RestControllerAdvice

🟢 4. Validation (Jakarta / Hibernate Validator)

@Valid

@Validated

@NotNull

@NotEmpty

@NotBlank

@Size

@Min

@Max

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 18/2417/02/2026, 16:47 Spring Boot Annotations List

@Positive

@Negative

@Email

@Pattern

@Future

@Past

@Digits

@AssertTrue

@AssertFalse

🟢 5. Persistence / JPA / Hibernate

Entity

@Entity

@Table

@Id

@GeneratedValue

@Column

@Transient

@Lob

@Enumerated

@Temporal

@Version

Relations

@OneToOne

@OneToMany

@ManyToOne

@ManyToMany

@JoinColumn

@JoinTable

@MapsId

@MapKey

@OrderBy

@OrderColumn

@Embedded

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 19/2417/02/2026, 16:47 Spring Boot Annotations List

@Embeddable

🟢 6. Spring Data

@Repository

@EnableJpaRepositories

@Query

@NamedQuery

@NamedNativeQuery

@Modifying

@Param

@Procedure

@Transactional

@Lock

@EntityGraph

🟢 7. Transaction Management

@Transactional

@EnableTransactionManagement

🟢 8. Security (Spring Security)

@EnableWebSecurity

@EnableMethodSecurity

@Secured

@RolesAllowed

@PreAuthorize

@PostAuthorize

@PreFilter

@PostFilter

@AuthenticationPrincipal

🟢 9. Scheduling & Async

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@EnableScheduling

@Scheduled

@EnableAsync

@Async

🟢 10. Cache

@EnableCaching

@Cacheable

@CachePut

@CacheEvict

@Caching

🟢 11. AOP

@Aspect

@Before

@After

@AfterReturning

@AfterThrowing

@Around

@Pointcut

@EnableAspectJAutoProxy

🟢 12. Messaging (Kafka / JMS / RabbitMQ)

@EnableKafka

@KafkaListener

@SendTo

@EnableJms

@JmsListener

@RabbitListener

@RabbitHandler

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 21/2417/02/2026, 16:47 Spring Boot Annotations List

🟢 13. Spring Cloud / Microservices

@EnableDiscoveryClient

@EnableEurekaClient

@FeignClient

@EnableFeignClients

@LoadBalanced

@RefreshScope

@Retryable

@Recover

@CircuitBreaker

🟢 14. Conditional (Auto Configuration)

@Conditional

@ConditionalOnBean

@ConditionalOnMissingBean

@ConditionalOnProperty

@ConditionalOnClass

@ConditionalOnMissingClass

@ConditionalOnWebApplication

@ConditionalOnNotWebApplication

@ConditionalOnExpression

🟢 15. Actuator

@Endpoint

@ReadOperation

@WriteOperation

@DeleteOperation

@EndpointWebExtension

🟢 16. Internationalization / Formatting

@DateTimeFormat

@NumberFormat

https://chatgpt.com/c/69944d3b-e6c4-83a3-bde2-f701e83c8151 22/2417/02/2026, 16:47 Spring Boot Annotations List

🟢 17. Testing

@RunWith

@ExtendWith

@Test

@BeforeEach

@AfterEach

@BeforeAll

@AfterAll

@SpringBootTest

@WebMvcTest

@DataJpaTest

@JdbcTest

@JsonTest

@RestClientTest

@AutoConfigureMockMvc

@AutoConfigureTestDatabase

@TestPropertySource

@ActiveProfiles

@DirtiesContext

⚠ Note:

There is no official single list of “every annotation” because Spring = multiple

frameworks + Jakarta EE + Spring Cloud + Testing + new

versions.

This list covers 95% of annotations used in enterprise Spring Boot projects.

If you

want, next I can give you this in:

✅ PDF cheat sheet

✅ Excel sheet

✅ Mind map diagram

✅ Top 50 most important annotations only

✅ Module-wise (spring-core, spring-web, spring-data, spring-security) list

Just say which one: PDF / EXCEL / DIAGRAM / TOP50 / M

ODULE-WISE

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