The Spring Cloud Azure Resource Manager is an abstract layer for azure-resource-manager. It can read metadata from ARM as well as create resources.

SpringResourceManagerUsages.java

// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License.

/**
 * The Spring Cloud Azure Resource Manager is an abstract layer for azure-resource-manager. It can read metadata from ARM
 * as well as create resources.
 */
public class SpringResourceManagerUsages {
    
    
    //===================
    // Demos how *ArmConnectionStringProvider will be used in a Spring Boot application. These beans are created by our autoconfiguration module.
    
    // Support Azure Event Hubs for Apache Kafka in the auto-configuration, which requires us to auto-configure a 
    // KafkaProperties bean. But we will only configure such bean if we detect that a connection string for Event Hubs 
    // is provided in current application context. This connection string can be retrieved via ARM.
    
    // An EventHubsArmConnectionStringProvider will be created if azure-resourcemanager is on the classpath
    // https://github.com/Azure/azure-sdk-for-java/blob/9121aa08d9ae802b16618ed576203dff331e1696/sdk/spring/spring-cloud-azure-autoconfigure/src/main/java/com/azure/spring/cloud/autoconfigure/resourcemanager/AzureEventHubsResourceManagerAutoConfiguration.java#L42-L51
    // And then the KafkaProperties bean configuration will pick up this connection string provider: https://github.com/Azure/azure-sdk-for-java/blob/92af61521f76ea60e95cd5cec521ab1cf1c4d246/sdk/spring/spring-cloud-azure-autoconfigure/src/main/java/com/azure/spring/cloud/autoconfigure/eventhubs/AzureEventHubsClientBuilderConfiguration.java#L43
    @Bean
    @ConditionalOnMissingBean
    @ConditionalOnProperty(prefix = AzureEventHubsProperties.PREFIX, value = "namespace")
    @ConditionalOnMissingProperty(prefix = AzureEventHubsProperties.PREFIX, value = "connection-string")
    @Order
    public EventHubsArmConnectionStringProvider eventHubsArmConnectionStringProvider() {

        return new EventHubsArmConnectionStringProvider(this.azureResourceManager, resourceMetadata,
            resourceMetadata.getName());
    }
    
    //===================
    // Demos how *EventHubsProvisioner will be used in a Spring Cloud Stream application. 
    // This bean will be pick up by the configuration of a EventHubsChannelProvisioner: 
    // https://github.com/Azure/azure-sdk-for-java/blob/9121aa08d9ae802b16618ed576203dff331e1696/sdk/spring/spring-cloud-azure-stream-binder-eventhubs/src/main/java/com/azure/spring/cloud/stream/binder/eventhubs/config/EventHubsBinderConfiguration.java#L55-L58
    @Bean
    public EventHubsProvisioner myEventHubsProvisioner() {
        return new EventHubsProvisioner() {
            @Override
            public void provisionNamespace(String namespace) {
                // provision the namespace
            }

            @Override
            public void provisionEventHub(String namespace, String eventHub) {
                // provision the event hub
            }

            @Override
            public void provisionConsumerGroup(String namespace, String eventHub, String consumerGroup) {
                // provision the consumer group;
            }
        };
    }
    
}

Where is azureResourceManager set? Is it injected by Spring, are there any annotations missing, etc?