Ensure custom HTTP code mappings for /health don't remove default mappings

Previously any custom http code mapping would remove the default mappings. With this commit the behaviour is changed so that default mappings will stay if a custom mapping is registered. Certainly a default mapping can be overridden.

fixes #1264

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/autoconfigure/EndpointWebMvcAutoConfiguration.java

@@ -157,7 +157,7 @@ public class EndpointWebMvcAutoConfiguration implements ApplicationContextAware,
 	public HealthMvcEndpoint healthMvcEndpoint(HealthEndpoint delegate) {
 		HealthMvcEndpoint healthMvcEndpoint = new HealthMvcEndpoint(delegate);
 		if (this.healthMvcEndpointProperties.getMapping() != null) {
-			healthMvcEndpoint.setStatusMapping(this.healthMvcEndpointProperties
+			healthMvcEndpoint.addStatusMapping(this.healthMvcEndpointProperties
 					.getMapping());
 		}
 		return healthMvcEndpoint;

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/mvc/HealthMvcEndpoint.java

@@ -50,7 +50,7 @@ public class HealthMvcEndpoint extends EndpointMvcAdapter {
 	}
 
 	/**
-	 * Set specific status mappings
+	 * Set specific status mappings.
 	 * @param statusMapping a map of status code to {@link HttpStatus}
 	 */
 	public void setStatusMapping(Map<String, HttpStatus> statusMapping) {
@@ -59,7 +59,16 @@ public class HealthMvcEndpoint extends EndpointMvcAdapter {
 	}
 
 	/**
-	 * Add a status mapping to the existing set
+	 * Add specfic status mappings to the existing set.
+	 * @param statusMapping a map of status code to {@link HttpStatus}
+	 */
+	public void addStatusMapping(Map<String, HttpStatus> statusMapping) {
+		Assert.notNull(statusMapping, "StatusMapping must not be null");
+		this.statusMapping.putAll(statusMapping);
+	}
+
+	/**
+	 * Add a status mapping to the existing set.
 	 * @param status the status to map
 	 * @param httpStatus the http status
 	 */
@@ -70,7 +79,7 @@ public class HealthMvcEndpoint extends EndpointMvcAdapter {
 	}
 
 	/**
-	 * Add a status mapping to the existing set
+	 * Add a status mapping to the existing set.
 	 * @param statusCode the status code to map
 	 * @param httpStatus the http status
 	 */