Native Images Support

Starting with version 6.0, GraalVM compilation of Spring Integration applications to native images is supported by Spring AOT native hints. For most common use cases, such as endpoint definitions with @Bean methods, Java DSL configuration with lambdas and @MessagingGateway interface scanning (importing), the framework provides respective reflection, proxy and serialization hints. If configuration uses messaging annotations (@ServiceActivator, @Splitter etc.) on POJO methods, or POJO methods are used with the IntegrationFlowBuilder.handle(Object service, String methodName) API, they have to be also marked with a @Reflective annotation since they are invoked by the framework reflectively.

XML configuration is not supported for native images.

As stated before, service interfaces with the @MessagingGateway annotation, when they are scanned by the @IntegrationComponentScan or used in an @Import annotation, are processed by the framework and the respective proxy hint is exposed into the AOT contribution. When gateways are declared using the IntegrationFlow.from(Class<?> serviceInterface) API, the proxy configured for such interfaces have to be exposed manually:

@Configuration
@EnableIntegration
@ImportRuntimeHints(GatewayRuntimeHints.class)
public class IntegrationConfiguration {

    @Bean
    IntegrationFlow someFlow() {
        return IntegrationFlow.from(SomeGateway)
                  // ...
                   .get();
    }

    public interface SomeGateway {

        void doSomething(Object payload);

    }

    private static class GatewayRuntimeHints implements RuntimeHintsRegistrar {

        @Override
        public void registerHints(RuntimeHints hints, ClassLoader classLoader) {
            hints.proxies().registerJdkProxy(
                                   AopProxyUtils.completeJdkProxyInterfaces(SomeGateway));
        }

    }

}

The IntegrationFlow content is not processed during the AOT processing phase. Therefore, some hints, such as the one mentioned above for a gateway proxy, must be provided by the target application.

Of course, configuration is just a piece of an integration solution. The most important part is data transferring over the network as well as persistent storage. That’s where serialization comes handy for many use-cases. Spring Integration exposes serialization hints into a native image configuration for these types used by the framework internally: String, Number, Long, Date, ArrayList, HashMap, Properties, Hashtable, Exception, UUID, GenericMessage, ErrorMessage, MessageHeaders, AdviceMessage, MutableMessage, MutableMessageHeaders, MessageGroupMetadata, MessageHolder, MessageMetadata, MessageHistory, MessageHistory.Entry, DelayHandler.DelayedMessageWrapper. For user specific data, mostly present as a message payload, the serialization hint must be exposed manually via a RuntimeHintsRegistrar implementation, as is shown above for a gateway proxy, and the respective RuntimeHints.serialization().registerType() API.

It is recommended that native integration applications are developed with Spring Boot, using its respective build tools.