Consistent final declaration for static delegate classes

Issue: SPR-16968

spring-aop/src/main/java/org/springframework/aop/framework/AopContext.java

@@ -39,7 +39,7 @@ import org.springframework.lang.Nullable;
  * @author Juergen Hoeller
  * @since 13.03.2003
  */
-public abstract class AopContext {
+public final class AopContext {
 
 	/**
 	 * ThreadLocal holder for AOP proxy associated with this thread.
@@ -50,6 +50,10 @@ public abstract class AopContext {
 	private static final ThreadLocal<Object> currentProxy = new NamedThreadLocal<>("Current AOP proxy");
 
 
+	private AopContext() {
+	}
+
+
 	/**
 	 * Try to return the current AOP proxy. This method is usable only if the
 	 * calling method has been invoked via AOP, and the AOP framework has been set

spring-aop/src/main/java/org/springframework/aop/framework/adapter/GlobalAdvisorAdapterRegistry.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -24,7 +24,11 @@ package org.springframework.aop.framework.adapter;
  * @author Phillip Webb
  * @see DefaultAdvisorAdapterRegistry
  */
-public abstract class GlobalAdvisorAdapterRegistry {
+public final class GlobalAdvisorAdapterRegistry {
+
+	private GlobalAdvisorAdapterRegistry() {
+	}
+
 
 	/**
 	 * Keep track of a single instance so we can return it to classes that request it.

spring-beans/src/main/java/org/springframework/beans/PropertyAccessorFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2008 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -24,7 +24,11 @@ package org.springframework.beans;
  * @author Juergen Hoeller
  * @since 2.5.2
  */
-public abstract class PropertyAccessorFactory {
+public final class PropertyAccessorFactory {
+
+	private PropertyAccessorFactory() {
+	}
+
 
 	/**
 	 * Obtain a BeanWrapper for the given target object,

spring-context/src/main/java/org/springframework/context/i18n/LocaleContextHolder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -42,7 +42,7 @@ import org.springframework.lang.Nullable;
  * @see org.springframework.context.support.MessageSourceAccessor
  * @see org.springframework.web.servlet.DispatcherServlet
  */
-public abstract class LocaleContextHolder {
+public final class LocaleContextHolder {
 
 	private static final ThreadLocal<LocaleContext> localeContextHolder =
 			new NamedThreadLocal<>("LocaleContext");
@@ -59,6 +59,10 @@ public abstract class LocaleContextHolder {
 	private static TimeZone defaultTimeZone;
 
 
+	private LocaleContextHolder() {
+	}
+
+
 	/**
 	 * Reset the LocaleContext for the current thread.
 	 */

spring-core/src/main/java/org/springframework/core/BridgeMethodResolver.java

@@ -45,7 +45,11 @@ import org.springframework.util.ReflectionUtils;
  * @author Phillip Webb
  * @since 2.0
  */
-public abstract class BridgeMethodResolver {
+public final class BridgeMethodResolver {
+
+	private BridgeMethodResolver() {
+	}
+
 
 	/**
 	 * Find the original method for the supplied {@link Method bridge Method}.

spring-core/src/main/java/org/springframework/core/CollectionFactory.java

@@ -53,7 +53,7 @@ import org.springframework.util.ReflectionUtils;
  * @author Sam Brannen
  * @since 1.1.1
  */
-public abstract class CollectionFactory {
+public final class CollectionFactory {
 
 	private static final Set<Class<?>> approximableCollectionTypes = new HashSet<>();
 
@@ -85,6 +85,10 @@ public abstract class CollectionFactory {
 	}
 
 
+	private CollectionFactory() {
+	}
+
+
 	/**
 	 * Determine whether the given collection type is an <em>approximable</em> type,
 	 * i.e. a type that {@link #createApproximateCollection} can approximate.

spring-core/src/main/java/org/springframework/core/Conventions.java

@@ -34,7 +34,7 @@ import org.springframework.util.ClassUtils;
  * @author Rossen Stoyanchev
  * @since 2.0
  */
-public abstract class Conventions {
+public final class Conventions {
 
 	/**
 	 * Suffix added to names when using arrays.
@@ -42,6 +42,10 @@ public abstract class Conventions {
 	private static final String PLURAL_SUFFIX = "List";
 
 
+	private Conventions() {
+	}
+
+
 	/**
 	 * Determine the conventional variable name for the supplied {@code Object}
 	 * based on its concrete type. The convention used is to return the

spring-core/src/main/java/org/springframework/core/GenericTypeResolver.java

@@ -41,13 +41,17 @@ import org.springframework.util.ConcurrentReferenceHashMap;
  * @author Phillip Webb
  * @since 2.5.2
  */
-public abstract class GenericTypeResolver {
+public final class GenericTypeResolver {
 
 	/** Cache from Class to TypeVariable Map. */
 	@SuppressWarnings("rawtypes")
 	private static final Map<Class<?>, Map<TypeVariable, Type>> typeVariableCache = new ConcurrentReferenceHashMap<>();
 
 
+	private GenericTypeResolver() {
+	}
+
+
 	/**
 	 * Determine the target type for the given generic parameter type.
 	 * @param methodParameter the method parameter specification
@@ -86,7 +90,7 @@ public abstract class GenericTypeResolver {
 	 */
 	@Nullable
 	public static Class<?> resolveReturnTypeArgument(Method method, Class<?> genericIfc) {
-		Assert.notNull(method, "method must not be null");
+		Assert.notNull(method, "Method must not be null");
 		ResolvableType resolvableType = ResolvableType.forMethodReturnType(method).as(genericIfc);
 		if (!resolvableType.hasGenerics() || resolvableType.getType() instanceof WildcardType) {
 			return null;

spring-core/src/main/java/org/springframework/core/MethodIntrospector.java

@@ -38,7 +38,11 @@ import org.springframework.util.ReflectionUtils;
  * @author Rossen Stoyanchev
  * @since 4.2.3
  */
-public abstract class MethodIntrospector {
+public final class MethodIntrospector {
+
+	private MethodIntrospector() {
+	}
+
 
 	/**
 	 * Select methods on the given target type based on the lookup of associated metadata.

spring-core/src/main/java/org/springframework/core/SpringProperties.java

@@ -46,7 +46,7 @@ import org.springframework.lang.Nullable;
  * @see org.springframework.jdbc.core.StatementCreatorUtils#IGNORE_GETPARAMETERTYPE_PROPERTY_NAME
  * @see org.springframework.test.context.cache.ContextCache#MAX_CONTEXT_CACHE_SIZE_PROPERTY_NAME
  */
-public abstract class SpringProperties {
+public final class SpringProperties {
 
 	private static final String PROPERTIES_RESOURCE_LOCATION = "spring.properties";
 
@@ -79,6 +79,10 @@ public abstract class SpringProperties {
 	}
 
 
+	private SpringProperties() {
+	}
+
+
 	/**
 	 * Programmatically set a local property, overriding an entry in the
 	 * {@code spring.properties} file (if any).

spring-core/src/main/java/org/springframework/core/convert/support/ConversionServiceFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -33,7 +33,11 @@ import org.springframework.lang.Nullable;
  * @author Chris Beams
  * @since 3.0
  */
-public abstract class ConversionServiceFactory {
+public final class ConversionServiceFactory {
+
+	private ConversionServiceFactory() {
+	}
+
 
 	/**
 	 * Register the given Converter objects with the given target ConverterRegistry.

spring-core/src/main/java/org/springframework/core/io/support/SpringFactoriesLoader.java

@@ -60,7 +60,7 @@ import org.springframework.util.StringUtils;
  * @author Sam Brannen
  * @since 3.2
  */
-public abstract class SpringFactoriesLoader {
+public final class SpringFactoriesLoader {
 
 	/**
 	 * The location to look for factories.
@@ -74,6 +74,10 @@ public abstract class SpringFactoriesLoader {
 	private static final Map<ClassLoader, MultiValueMap<String, String>> cache = new ConcurrentReferenceHashMap<>();
 
 
+	private SpringFactoriesLoader() {
+	}
+
+
 	/**
 	 * Load and instantiate the factory implementations of the given type from
 	 * {@value #FACTORIES_RESOURCE_LOCATION}, using the given class loader.