To support Spring transaction management we need to declare a PlatformTransactionManager bean. The @Bean method should be named transactionManager. It can return a JpaTransactionManager, DataSourceTransactionManager, JmsTransactionManager, JtaTransactionManager, etc:

    @Bean
    public PlatformTransactionManager transactionManager(){
        return new DataSourceTransactionManager(dataSource());
    }

Now, we need to declare the transactional methods, it may be applied at the class level (to all its methods) or in the interface (since Spring 5.0):

    @Transactional
    public Response transactions(Request request) {
        ...
    }   

Finally, we need to add an annotation to instruct the container to look for the @Transactional annotation:

@Configuration
@EnableTransactionManagement
public class AppConfig { ... }

Spring creates proxies for all the classes annotated with @Transactional (using around advice - see Spring AOP). The proxy implements the following behavior:

• Transaction started before entering the method
• Commit at the end of the method
• Rollback if the method throws a RuntimeException