Spring code explainers

java

@GetMapping("/files/{id}")
public ResponseEntity<StreamingResponseBody> download(
        @PathVariable String id,
        @RequestHeader(value = HttpHeaders.RANGE, required = false) String rangeHeader) throws IOException {

HTTP range requests in Spring

http-range streaming file-io

Advanced 10 steps

java

@Configuration
public class UserImportJobConfig {
 
    @Bean

How a Spring Batch CSV import job is wired

batch processing chunk oriented fault tolerance

Intermediate 10 steps

java

@AutoConfiguration
@EnableConfigurationProperties(RateLimiterProperties.class)
@ConditionalOnClass(RateLimiter.class)
public class RateLimiterAutoConfiguration {

Building a Spring Boot rate-limiter auto-config

auto-configuration conditional-beans rate-limiting

Intermediate 7 steps

java

public URI buildSearchUri(String query, int page, int size, List<String> tags) {
    UriComponentsBuilder builder = UriComponentsBuilder
            .fromUriString("https://api.example.com")
            .path("/v2/products/search")

Building URIs safely with UriComponentsBuilder in Spring

url-building builder-pattern encoding

Intermediate 5 steps

java

@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {

Real-time chat over STOMP WebSockets in Spring

websockets stomp messaging

Intermediate 8 steps

java

@Configuration
@EnableRedisHttpSession(namespace = "myapp:sessions", maxInactiveIntervalInSeconds = 1800, flushMode = FlushMode.IMMEDIATE)
public class SessionConfig {

Backing HTTP sessions with Redis in Spring

session-management redis distributed-state

Intermediate 7 steps

java

@Configuration
@EnableBatchProcessing
public class CustomerImportJobConfig {

How a chunk-based CSV import job works in Spring

batch-processing etl csv-parsing

Intermediate 9 steps

java

@Configuration
@EnableWebSecurity
public class ResourceServerConfig {

Configuring a JWT resource server in Spring

oauth2 jwt authorization

Intermediate 8 steps

java

@Configuration
public class OrderConsumerConfig {
 
    @Bean

Wiring a resilient Kafka consumer in Spring

kafka deserialization error-handling

Intermediate 8 steps

java

@Configuration
@EnableKafka
public class KafkaErrorHandlingConfig {

Kafka retry and dead-letter handling in Spring

kafka error-handling retry

Intermediate 7 steps

java

@Controller
@RequestMapping("/employees")
public class EmployeeController {

Customizing form binding in a Spring MVC controller

data-binding validation type-conversion

Intermediate 9 steps

java

package com.example.config.condition;
 
import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;

A custom @Conditional feature flag in Spring

conditional beans feature flags annotations

Intermediate 7 steps

java

@Component
public class OrderRecoveryHandler {
 
    private final RabbitTemplate rabbitTemplate;

Dead-letter recovery with Spring AMQP

dead-letter-queue retry exponential-backoff

Advanced 9 steps

java

@Component
public class CorrelationIdWebFilter implements WebFilter, Ordered {
 
    public static final String CORRELATION_ID_HEADER = "X-Correlation-Id";

Correlation IDs in a Spring WebFlux filter

reactive web filter correlation id

Advanced 7 steps

java

@Component
public class InventoryReconciliationJob {
 
    private static final Logger log = LoggerFactory.getLogger(InventoryReconciliationJob.class);

Distributed scheduled jobs with Spring locks

distributed-locking scheduling concurrency

Advanced 8 steps

java

@Configuration
@EnableWebSecurity
public class OAuth2SecurityConfig {

How OIDC login works in Spring Security

oauth2 openid-connect authorization

Intermediate 8 steps

java

@RestController
@RequestMapping("/api/reports")
public class OrderReportController {

Streaming a CSV export in Spring

streaming csv-export backpressure

Intermediate 9 steps

java

@Repository
public interface OrderRepository extends JpaRepository<Order, Long> {
 
    @Query("""

Keyset pagination with Spring Data JPA

pagination cursor jpa

Advanced 8 steps