Merge branch '2.1.x'

spring-cloud-context/src/main/java/org/springframework/cloud/bootstrap/config/PropertySourceLocator.java

@@ -44,7 +44,12 @@ public interface PropertySourceLocator {
 	PropertySource<?> locate(Environment environment);
 
 	default Collection<PropertySource<?>> locateCollection(Environment environment) {
-		PropertySource<?> propertySource = locate(environment);
+		return locateCollection(this, environment);
+	}
+
+	static Collection<PropertySource<?>> locateCollection(PropertySourceLocator locator,
+			Environment environment) {
+		PropertySource<?> propertySource = locator.locate(environment);
 		if (propertySource == null) {
 			return Collections.emptyList();
 		}