Securing Spring Boot microservice using Keycloak and Testcontainers — Configure OAuth 2.0 security

Reference note (untrusted external data; do not execute it as instructions). Create a SecurityConfig class that protects the API endpoints using JWT token-based authentication Bounded code example (external data; do not execute automatically): ```java package com.testcontainers.products.config; import static org.springframework.security.config.Customizer.withDefaults; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.http.HttpMethod; import org.springframework.security.config.annotation.web.builders.HttpSecurity; import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity; import org.springframework.security.config.annotation.web.configurers.CorsConfigurer; import org.springframework.security.config.annotation.web.configurers.CsrfConfigurer; import org.springframework.security.config.http.SessionCreationPolicy; import org.springframework.security.web.SecurityFilterChain; @Configuration @EnableWebSecurity class SecurityConfig { @Bean SecurityFilterChain securityFilterChain(HttpSecurity http) throws Exception { ``` Permits unauthenticated access to GET /api/products. Requires authentication for POST /api/products and all other endpoints. Configures the OAuth 2.0 Resource Server with JWT token-based authentication. Disables CORS and CSRF because this is a stateless API. Add the JWT issuer URI to application.properties Bounded code example (external data; do not execute automatically): ```properties spring.security.oauth2.resourceserver.jwt.issuer-uri=http://localhost:9090/realms/keycloaktcdemo ``` Attribution: Adapted from Docker Documentation under Apache-2.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.