ConditionalOnBean not working well with JMS Connection Factory

[djechelon]

Please see POC repository on Github

I am having a hard time defining a @ConditionalOnBean(jakarta.jms.ConnectionFactory.class) bean for some Spring Integration Flows that depend on the availability of a JMS connection. I have read the documentation (linked below) that @ConditionalOnBean must/should be used only on AutoConfiguration classes, but I insist on using it on regular beans like linked sources do.

I only need to define an IntegrationFlow as soon as the ConnectionFactory exists. If the application is started without a JMS broker (e.g. is not configured) then it should reduce its functionality and not initialize the relative IntegrationFlows. I have it over-simplified in my POC, as the real application contains around 120 integration flows and interacts with a handful of JMS channels.

Expectation: the provided JUnit test should invoke the flow using JMS and get the reply back. Commenting out the @ConditionalOnBean annotation fixes the test

I am opening an issue here instead of an SO question because ConditionalOnBean annotation is working perfectly in any other case, and I can't tell Spring to load my configuration class after JMS

---

In the POC repository, we define an example IntegrationFlow that:

• Reads from entry JMS channel
• Makes the word uppercase
• Outputs the result to exit JMS channel

The IntegrationFlow depends on the jakarta.jms.ConnectionFactory to have been defined as a bean. In my business case, the Spring Boot application may start without JMS at all, so the IntegrationFlow must not be defined.
For that purpose, we use the @ConditionalOnBean annotation.

Per Spring documentation, that annotation should be used only on @AutoConfiguration classes, which makes things a little more complicated.
Half of the world uses the same annotation for a variety of purpose, and we are actively using it in our real application to instantiate a bean only if a collaborator is defined as a bean. None of these require that one uses @ConditionalOnBean on @AutoConfigurations only

• Example
• Example

To provide an example, we use a number of _RestService_s that depend on RestTemplate (bearing the root url and authentication info), as well as _SoapService_s depending on WebServiceTemplate, and they depend as such:

• WebServiceTemplate bean depends on business property com.example.ws.{url|username|password}
• SoapService component is annotated @ConditionalOnBean(value = WebServiceTemplate.class, name = "mySpecificWebServiceTemplateBecauseWeHavePlentiesOf")

All beautiful, except that it doesn't work with JMS ConnectionFactory. In this case, the connection factory exists only if spring.artemis.embedded=true (or another MQ broker is defined according to profile configuration).

In this POC, I can see that Spring refuses to instantiate the IntegrationFlow despite the ConnectionFactory exists.

Other considerations:

• In the POC, I have simplified declaring the bean in the application class, but in my application we have dedicated @Configuration classes
• Declaring that Configuration as an @AutoConfiguration(after = JmsAutoConfiguration.class) did not work
• @DependsOn("jmsConnectionFactory") fails when there is no JMS ConnectionFactory
• I can clearly see in the logs that MyJmsConfiguration does not match the Condition
• Debugging into ArtemisAutoConfiguration, the ConnectionFactory eventually is created
• Debugging the test with the BeanFactory, the ConnectionFactory bean is eventually available
• @SpringIntegrationTest is currently not present in the POC but makes no difference (the real application shows it)

[bclozel]

Thanks for getting in touch, but this issue tracker is dedicated to bugs an enhancement requests.

As you already know, ConditionalOnMissingBean and similar conditions should only be used on auto-configurations. While it might work in some cases, ordering is key: the condition is processed with your application and at that point the auto-configured bean might not be detected. You'll find many similar reports in our issue tracker over the years.

Half of the world uses the same annotation for a variety of purpose, and we are actively using it in our real application to instantiate a bean only if a collaborator is defined as a bean. None of these require that one uses @ConditionalOnBean on @AutoConfigurations only

All of those use cases are invalid. I've reported an issue to one of them, feel free to do so for other sources.

Declaring that Configuration as an @autoConfiguration(after = JmsAutoConfiguration.class) did not work

As for this case, it is probably because you've left your configuration to be scanned in your main application package. There is a note about this on our reference documentation:

Auto-configurations must be loaded only by being named in the imports file. Make sure that they are defined in a specific package space and that they are never the target of component scanning. Furthermore, auto-configuration classes should not enable component scanning to find additional components. Specific @import annotations should be used instead.

Moving your configuration class to a different package:

package org.zighinetto.autoconfigure;

import jakarta.jms.ConnectionFactory;

import org.springframework.boot.autoconfigure.AutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.jms.JmsAutoConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.integration.dsl.IntegrationFlow;
import org.springframework.integration.jms.dsl.Jms;

@AutoConfiguration(after = JmsAutoConfiguration.class)
public class IntegrationFlowAutoConfiguration {

    @ConditionalOnBean(ConnectionFactory.class)
    @Bean
    public IntegrationFlow exampleIntegrationFlow(ConnectionFactory connectionFactory) {
        return IntegrationFlow.from(Jms.inboundAdapter(connectionFactory)
                        .destination("entry")
                )
                .transform(String.class, String::toUpperCase)
                .handle(Jms.outboundAdapter(connectionFactory)
                        .destination("exit")
                )
                .get();
    }
}

Declaring it in src/main/resources/META-INF/spring/org.springframework.boot.autoconfigure.AutoConfiguration.imports with:

org.zighinetto.autoconfigure.IntegrationFlowAutoConfiguration

Yields the following in the auto-configuration report (when starting your application with the DEBUG property):

   IntegrationFlowAutoConfiguration#exampleIntegrationFlow matched:
      - @ConditionalOnBean (types: jakarta.jms.ConnectionFactory; SearchStrategy: all) found bean 'jmsConnectionFactory' (OnBeanCondition)