[Spring] Useless methods in ApiDelegate interface on java8

By default, when java8 is used, the ApiDelegate interfaces get default implementations that return a server error and 3 supporting methods that are supposed to be customized.

However if you disable defaultInterfaces, no method body on the APIs get generated, but the 3 supporting methods still are, even though they are unused.

I would propose the following change to the apiDelegate.mustache template to correct this. If that is something you'd consider merging I can also create a pull request for it.

Index: src/main/resources/handlebars/JavaSpring/apiDelegate.mustache
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- src/main/resources/handlebars/JavaSpring/apiDelegate.mustache	(revision 5737ffebb86be3c7fa5f098155d77e706d089d08)
+++ src/main/resources/handlebars/JavaSpring/apiDelegate.mustache	(date 1581672639198)
@@ -42,20 +42,21 @@
 {{>generatedAnnotation}}
 public interface {{classname}}Delegate {
 {{#jdk8}}
-
+{{#defaultInterfaces}}
     Logger log = LoggerFactory.getLogger({{classname}}.class);
 
-    {{#defaultInterfaces}}default {{/defaultInterfaces}}Optional<ObjectMapper> getObjectMapper(){{^defaultInterfaces}};{{/defaultInterfaces}}{{#defaultInterfaces}}{
+    default Optional<ObjectMapper> getObjectMapper() {
         return Optional.empty();
-    }{{/defaultInterfaces}}
+    }
 
-    {{#defaultInterfaces}}default {{/defaultInterfaces}}Optional<HttpServletRequest> getRequest(){{^defaultInterfaces}};{{/defaultInterfaces}}{{#defaultInterfaces}}{
+    default Optional<HttpServletRequest> getRequest() {
         return Optional.empty();
-    }{{/defaultInterfaces}}
+    }
 
-    {{#defaultInterfaces}}default Optional<String> getAcceptHeader() {
+    default Optional<String> getAcceptHeader() {
         return getRequest().map(r -> r.getHeader("Accept"));
-    }{{/defaultInterfaces}}
+    }
+{{/defaultInterfaces}}
 {{/jdk8}}
 
 {{#operation}}

Start with src/main/resources/handlebars/JavaSpring/apiDelegate.mustache and compare the jdk8 and defaultInterfaces template branches. Generate or inspect Java 8 Spring output with defaultInterfaces disabled, then confirm the supporting methods are absent while the generated delegate interface remains valid.