Use overriding rather than overridden getter methods in config prop AP

Fixes gh-23966

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/main/java/org/springframework/boot/configurationprocessor/TypeElementMembers.java

 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -74,7 +74,7 @@ class TypeElementMembers {
 	private void processMethod(ExecutableElement method) {
 		if (isPublic(method)) {
 			String name = method.getSimpleName().toString();
-			if (isGetter(method) && !this.publicGetters.containsKey(name)) {
+			if (isGetter(method) && !this.publicGetters.containsKey(getAccessorName(name))) {
 				this.publicGetters.put(getAccessorName(name), method);
 			}
 			else if (isSetter(method)) {

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationprocessor/PropertyDescriptorResolverTests.java

 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -75,6 +75,10 @@ class PropertyDescriptorResolverTests {
 					PropertyDescriptorResolver resolver = new PropertyDescriptorResolver(metadataEnv);
 					assertThat(resolver.resolve(type, null).map(PropertyDescriptor::getName)).containsExactly("third",
 							"second", "first");
+					assertThat(resolver.resolve(type, null).map(
+							(descriptor) -> descriptor.getGetter().getEnclosingElement().getSimpleName().toString()))
+									.containsExactly("HierarchicalProperties", "HierarchicalPropertiesParent",
+											"HierarchicalPropertiesParent");
 					assertThat(resolver.resolve(type, null)
 							.map((descriptor) -> descriptor.resolveItemMetadata("test", metadataEnv))
 							.map(ItemMetadata::getDefaultValue)).containsExactly("three", "two", "one");

spring-boot-project/spring-boot-tools/spring-boot-configuration-processor/src/test/java/org/springframework/boot/configurationsample/simple/HierarchicalPropertiesParent.java

 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -33,7 +33,8 @@ public abstract class HierarchicalPropertiesParent extends HierarchicalPropertie
 		this.second = second;
 	}
 
-	// Useless override
+	// Overridden properties should belong to this class, not
+	// HierarchicalPropertiesGrandparent
 
 	@Override
 	public String getFirst() {