Auto-configure a ResourceConfig for Jersey endpoints if needed

See gh-11948

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/endpoint/web/jersey/JerseyWebEndpointManagementContextConfiguration.java

@@ -49,14 +49,21 @@ import org.springframework.context.annotation.Configuration;
  *
  * @author Andy Wilkinson
  * @author Phillip Webb
+ * @author Michael Simons
  */
 @Configuration
 @ConditionalOnWebApplication(type = Type.SERVLET)
 @ConditionalOnClass(ResourceConfig.class)
-@ConditionalOnBean({ ResourceConfig.class, WebEndpointsSupplier.class })
+@ConditionalOnBean(WebEndpointsSupplier.class)
 @ConditionalOnMissingBean(type = "org.springframework.web.servlet.DispatcherServlet")
 class JerseyWebEndpointManagementContextConfiguration {
 
+	@ConditionalOnMissingBean(ResourceConfig.class)
+	@Bean
+	public ResourceConfig resourceConfig() {
+		return new ResourceConfig();
+	}
+
 	@Bean
 	public ResourceConfigCustomizer webEndpointRegistrar(
 			WebEndpointsSupplier webEndpointsSupplier,

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/endpoint/web/jersey/JerseyWebEndpointManagementContextConfigurationTests.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2012-2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.actuate.autoconfigure.endpoint.web.jersey;
+
+import java.util.Collections;
+
+import org.glassfish.jersey.server.ResourceConfig;
+import org.junit.Test;
+
+import org.springframework.boot.actuate.autoconfigure.endpoint.web.WebEndpointAutoConfiguration;
+import org.springframework.boot.actuate.endpoint.web.WebEndpointsSupplier;
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.runner.WebApplicationContextRunner;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Michael Simons
+ */
+public class JerseyWebEndpointManagementContextConfigurationTests {
+
+	private final WebApplicationContextRunner runner = new WebApplicationContextRunner()
+			.withConfiguration(AutoConfigurations.of(WebEndpointAutoConfiguration.class, JerseyWebEndpointManagementContextConfiguration.class));
+
+	@Test
+	public void contextShouldContainSingleResourceConfig() {
+		this.runner
+			.withUserConfiguration(WebEndpointsSupplierConfig.class)
+			.run(context -> assertThat(context).hasSingleBean(ResourceConfig.class));
+	}
+
+	@Test
+	public void contextWhenResourceConfigExistsShouldContainSingleResourceConfig() {
+		this.runner
+			.withUserConfiguration(
+				WebEndpointsSupplierConfig.class,
+				ConfigWithResourceConfig.class)
+			.run(context -> {
+				assertThat(context).hasSingleBean(ResourceConfig.class);
+				assertThat(context).hasBean("customResourceConfig");
+		});
+	}
+
+	@Configuration
+	static class WebEndpointsSupplierConfig {
+
+		@Bean
+		public WebEndpointsSupplier webEndpointsSupplier() {
+			return () -> Collections.emptyList();
+		}
+	}
+
+	@Configuration
+	static class ConfigWithResourceConfig {
+
+		@Bean
+		public ResourceConfig customResourceConfig() {
+			return new ResourceConfig();
+		}
+	}
+}