Use consistent class design

Update all classes so that inner classes are always last. Also
ensure that utility classes are always final and have a private
constructor and make exceptions final whenever possible.

Issue: SPR-16968

spring-beans/src/main/java/org/springframework/beans/BeanInstantiationException.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.
@@ -31,13 +31,13 @@ import org.springframework.lang.Nullable;
 @SuppressWarnings("serial")
 public class BeanInstantiationException extends FatalBeanException {
 
-	private Class<?> beanClass;
+	private final Class<?> beanClass;
 
 	@Nullable
-	private Constructor<?> constructor;
+	private final Constructor<?> constructor;
 
 	@Nullable
-	private Method constructingMethod;
+	private final Method constructingMethod;
 
 
 	/**
@@ -58,6 +58,8 @@ public class BeanInstantiationException extends FatalBeanException {
 	public BeanInstantiationException(Class<?> beanClass, String msg, @Nullable Throwable cause) {
 		super("Failed to instantiate [" + beanClass.getName() + "]: " + msg, cause);
 		this.beanClass = beanClass;
+		this.constructor = null;
+		this.constructingMethod = null;
 	}
 
 	/**
@@ -71,6 +73,7 @@ public class BeanInstantiationException extends FatalBeanException {
 		super("Failed to instantiate [" + constructor.getDeclaringClass().getName() + "]: " + msg, cause);
 		this.beanClass = constructor.getDeclaringClass();
 		this.constructor = constructor;
+		this.constructingMethod = null;
 	}
 
 	/**
@@ -84,6 +87,7 @@ public class BeanInstantiationException extends FatalBeanException {
 	public BeanInstantiationException(Method constructingMethod, String msg, @Nullable Throwable cause) {
 		super("Failed to instantiate [" + constructingMethod.getReturnType().getName() + "]: " + msg, cause);
 		this.beanClass = constructingMethod.getReturnType();
+		this.constructor = null;
 		this.constructingMethod = constructingMethod;
 	}
 

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

@@ -71,7 +71,7 @@ import org.springframework.util.StringUtils;
  * @see #clearClassLoader(ClassLoader)
  * @see #forClass(Class)
  */
-public class CachedIntrospectionResults {
+public final class CachedIntrospectionResults {
 
 	/**
 	 * System property that instructs Spring to use the {@link Introspector#IGNORE_ALL_BEANINFO}

spring-beans/src/main/java/org/springframework/beans/InvalidPropertyException.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.
@@ -28,9 +28,9 @@ import org.springframework.lang.Nullable;
 @SuppressWarnings("serial")
 public class InvalidPropertyException extends FatalBeanException {
 
-	private Class<?> beanClass;
+	private final Class<?> beanClass;
 
-	private String propertyName;
+	private final String propertyName;
 
 
 	/**

spring-beans/src/main/java/org/springframework/beans/NotWritablePropertyException.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.
@@ -30,7 +30,7 @@ import org.springframework.lang.Nullable;
 public class NotWritablePropertyException extends InvalidPropertyException {
 
 	@Nullable
-	private String[] possibleMatches;
+	private final String[] possibleMatches;
 
 
 	/**
@@ -42,6 +42,7 @@ public class NotWritablePropertyException extends InvalidPropertyException {
 		super(beanClass, propertyName,
 				"Bean property '" + propertyName + "' is not writable or has an invalid setter method: " +
 				"Does the return type of the getter match the parameter type of the setter?");
+		this.possibleMatches = null;
 	}
 
 	/**
@@ -52,6 +53,7 @@ public class NotWritablePropertyException extends InvalidPropertyException {
 	 */
 	public NotWritablePropertyException(Class<?> beanClass, String propertyName, String msg) {
 		super(beanClass, propertyName, msg);
+		this.possibleMatches = null;
 	}
 
 	/**
@@ -63,6 +65,7 @@ public class NotWritablePropertyException extends InvalidPropertyException {
 	 */
 	public NotWritablePropertyException(Class<?> beanClass, String propertyName, String msg, Throwable cause) {
 		super(beanClass, propertyName, msg, cause);
+		this.possibleMatches = null;
 	}
 
 	/**

spring-beans/src/main/java/org/springframework/beans/PropertyAccessException.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.
@@ -31,7 +31,7 @@ import org.springframework.lang.Nullable;
 public abstract class PropertyAccessException extends BeansException {
 
 	@Nullable
-	private transient PropertyChangeEvent propertyChangeEvent;
+	private final PropertyChangeEvent propertyChangeEvent;
 
 
 	/**
@@ -52,6 +52,7 @@ public abstract class PropertyAccessException extends BeansException {
 	 */
 	public PropertyAccessException(String msg, @Nullable Throwable cause) {
 		super(msg, cause);
+		this.propertyChangeEvent = null;
 	}
 
 

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

@@ -40,7 +40,7 @@ import org.springframework.util.ObjectUtils;
 public class PropertyBatchUpdateException extends BeansException {
 
 	/** List of PropertyAccessException objects. */
-	private PropertyAccessException[] propertyAccessExceptions;
+	private final PropertyAccessException[] propertyAccessExceptions;
 
 
 	/**

spring-beans/src/main/java/org/springframework/beans/PropertyDescriptorUtils.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.
@@ -30,7 +30,12 @@ import org.springframework.util.ObjectUtils;
  * @author Chris Beams
  * @author Juergen Hoeller
  */
-class PropertyDescriptorUtils {
+final class PropertyDescriptorUtils {
+
+
+	private PropertyDescriptorUtils() {
+	}
+
 
 	/**
 	 * See {@link java.beans.FeatureDescriptor}.

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

@@ -517,7 +517,7 @@ public class PropertyEditorRegistrySupport implements PropertyEditorRegistry {
 	 * Holder for a registered custom editor with property name.
 	 * Keeps the PropertyEditor itself plus the type it was registered for.
 	 */
-	private static class CustomEditorHolder {
+	private static final class CustomEditorHolder {
 
 		private final PropertyEditor propertyEditor;
 

spring-beans/src/main/java/org/springframework/beans/factory/BeanCreationException.java

@@ -35,10 +35,10 @@ import org.springframework.lang.Nullable;
 public class BeanCreationException extends FatalBeanException {
 
 	@Nullable
-	private String beanName;
+	private final String beanName;
 
 	@Nullable
-	private String resourceDescription;
+	private final String resourceDescription;
 
 	@Nullable
 	private List<Throwable> relatedCauses;
@@ -50,6 +50,8 @@ public class BeanCreationException extends FatalBeanException {
 	 */
 	public BeanCreationException(String msg) {
 		super(msg);
+		this.beanName = null;
+		this.resourceDescription = null;
 	}
 
 	/**
@@ -59,6 +61,8 @@ public class BeanCreationException extends FatalBeanException {
 	 */
 	public BeanCreationException(String msg, Throwable cause) {
 		super(msg, cause);
+		this.beanName = null;
+		this.resourceDescription = null;
 	}
 
 	/**
@@ -69,6 +73,7 @@ public class BeanCreationException extends FatalBeanException {
 	public BeanCreationException(String beanName, String msg) {
 		super("Error creating bean with name '" + beanName + "': " + msg);
 		this.beanName = beanName;
+		this.resourceDescription = null;
 	}
 
 	/**
@@ -94,6 +99,7 @@ public class BeanCreationException extends FatalBeanException {
 				(resourceDescription != null ? " defined in " + resourceDescription : "") + ": " + msg);
 		this.resourceDescription = resourceDescription;
 		this.beanName = beanName;
+		this.relatedCauses = null;
 	}
 
 	/**

spring-beans/src/main/java/org/springframework/beans/factory/BeanDefinitionStoreException.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.
@@ -31,10 +31,10 @@ import org.springframework.lang.Nullable;
 public class BeanDefinitionStoreException extends FatalBeanException {
 
 	@Nullable
-	private String resourceDescription;
+	private final String resourceDescription;
 
 	@Nullable
-	private String beanName;
+	private final String beanName;
 
 
 	/**
@@ -43,6 +43,8 @@ public class BeanDefinitionStoreException extends FatalBeanException {
 	 */
 	public BeanDefinitionStoreException(String msg) {
 		super(msg);
+		this.resourceDescription = null;
+		this.beanName = null;
 	}
 
 	/**
@@ -52,6 +54,8 @@ public class BeanDefinitionStoreException extends FatalBeanException {
 	 */
 	public BeanDefinitionStoreException(String msg, @Nullable Throwable cause) {
 		super(msg, cause);
+		this.resourceDescription = null;
+		this.beanName = null;
 	}
 
 	/**
@@ -62,6 +66,7 @@ public class BeanDefinitionStoreException extends FatalBeanException {
 	public BeanDefinitionStoreException(@Nullable String resourceDescription, String msg) {
 		super(msg);
 		this.resourceDescription = resourceDescription;
+		this.beanName = null;
 	}
 
 	/**
@@ -73,6 +78,7 @@ public class BeanDefinitionStoreException extends FatalBeanException {
 	public BeanDefinitionStoreException(@Nullable String resourceDescription, String msg, @Nullable Throwable cause) {
 		super(msg, cause);
 		this.resourceDescription = resourceDescription;
+		this.beanName = null;
 	}
 
 	/**

spring-beans/src/main/java/org/springframework/beans/factory/BeanNotOfRequiredTypeException.java

@@ -29,13 +29,13 @@ import org.springframework.util.ClassUtils;
 public class BeanNotOfRequiredTypeException extends BeansException {
 
 	/** The name of the instance that was of the wrong type. */
-	private String beanName;
+	private final String beanName;
 
 	/** The required type. */
-	private Class<?> requiredType;
+	private final Class<?> requiredType;
 
 	/** The offending type. */
-	private Class<?> actualType;
+	private final Class<?> actualType;
 
 
 	/**

spring-beans/src/main/java/org/springframework/beans/factory/CannotLoadBeanClassException.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.
@@ -30,13 +30,13 @@ import org.springframework.lang.Nullable;
 public class CannotLoadBeanClassException extends FatalBeanException {
 
 	@Nullable
-	private String resourceDescription;
+	private final String resourceDescription;
 
 	@Nullable
-	private String beanName;
+	private final String beanName;
 
 	@Nullable
-	private String beanClassName;
+	private final String beanClassName;
 
 
 	/**

spring-beans/src/main/java/org/springframework/beans/factory/NoSuchBeanDefinitionException.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.
@@ -36,10 +36,10 @@ import org.springframework.lang.Nullable;
 public class NoSuchBeanDefinitionException extends BeansException {
 
 	@Nullable
-	private String beanName;
+	private final String beanName;
 
 	@Nullable
-	private ResolvableType resolvableType;
+	private final ResolvableType resolvableType;
 
 
 	/**
@@ -49,6 +49,7 @@ public class NoSuchBeanDefinitionException extends BeansException {
 	public NoSuchBeanDefinitionException(String name) {
 		super("No bean named '" + name + "' available");
 		this.beanName = name;
+		this.resolvableType = null;
 	}
 
 	/**
@@ -59,6 +60,7 @@ public class NoSuchBeanDefinitionException extends BeansException {
 	public NoSuchBeanDefinitionException(String name, String message) {
 		super("No bean named '" + name + "' available: " + message);
 		this.beanName = name;
+		this.resolvableType = null;
 	}
 
 	/**
@@ -85,6 +87,7 @@ public class NoSuchBeanDefinitionException extends BeansException {
 	 */
 	public NoSuchBeanDefinitionException(ResolvableType type) {
 		super("No qualifying bean of type '" + type + "' available");
+		this.beanName = null;
 		this.resolvableType = type;
 	}
 
@@ -96,6 +99,7 @@ public class NoSuchBeanDefinitionException extends BeansException {
 	 */
 	public NoSuchBeanDefinitionException(ResolvableType type, String message) {
 		super("No qualifying bean of type '" + type + "' available: " + message);
+		this.beanName = null;
 		this.resolvableType = type;
 	}
 

spring-beans/src/main/java/org/springframework/beans/factory/NoUniqueBeanDefinitionException.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.
@@ -33,10 +33,10 @@ import org.springframework.util.StringUtils;
 @SuppressWarnings("serial")
 public class NoUniqueBeanDefinitionException extends NoSuchBeanDefinitionException {
 
-	private int numberOfBeansFound;
+	private final int numberOfBeansFound;
 
 	@Nullable
-	private Collection<String> beanNamesFound;
+	private final Collection<String> beanNamesFound;
 
 
 	/**
@@ -48,6 +48,7 @@ public class NoUniqueBeanDefinitionException extends NoSuchBeanDefinitionExcepti
 	public NoUniqueBeanDefinitionException(Class<?> type, int numberOfBeansFound, String message) {
 		super(type, message);
 		this.numberOfBeansFound = numberOfBeansFound;
+		this.beanNamesFound = null;
 	}
 
 	/**
@@ -56,8 +57,9 @@ public class NoUniqueBeanDefinitionException extends NoSuchBeanDefinitionExcepti
 	 * @param beanNamesFound the names of all matching beans (as a Collection)
 	 */
 	public NoUniqueBeanDefinitionException(Class<?> type, Collection<String> beanNamesFound) {
-		this(type, beanNamesFound.size(), "expected single matching bean but found " + beanNamesFound.size() + ": " +
+		super(type, "expected single matching bean but found " + beanNamesFound.size() + ": " +
 				StringUtils.collectionToCommaDelimitedString(beanNamesFound));
+		this.numberOfBeansFound =  beanNamesFound.size();
 		this.beanNamesFound = beanNamesFound;
 	}
 

spring-beans/src/main/java/org/springframework/beans/factory/UnsatisfiedDependencyException.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 +33,7 @@ import org.springframework.util.StringUtils;
 public class UnsatisfiedDependencyException extends BeanCreationException {
 
 	@Nullable
-	private InjectionPoint injectionPoint;
+	private final InjectionPoint injectionPoint;
 
 
 	/**
@@ -49,6 +49,7 @@ public class UnsatisfiedDependencyException extends BeanCreationException {
 		super(resourceDescription, beanName,
 				"Unsatisfied dependency expressed through bean property '" + propertyName + "'" +
 				(StringUtils.hasLength(msg) ? ": " + msg : ""));
+		this.injectionPoint = null;
 	}
 
 	/**

spring-beans/src/main/java/org/springframework/beans/factory/config/PropertyPlaceholderConfigurer.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.
@@ -250,7 +250,7 @@ public class PropertyPlaceholderConfigurer extends PlaceholderConfigurerSupport
 	}
 
 
-	private class PropertyPlaceholderConfigurerResolver implements PlaceholderResolver {
+	private final class PropertyPlaceholderConfigurerResolver implements PlaceholderResolver {
 
 		private final Properties props;
 

spring-beans/src/main/java/org/springframework/beans/factory/support/BeanDefinitionBuilder.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.
@@ -34,7 +34,7 @@ import org.springframework.util.ObjectUtils;
  * @author Juergen Hoeller
  * @since 2.0
  */
-public class BeanDefinitionBuilder {
+public final class BeanDefinitionBuilder {
 
 	/**
 	 * Create a new {@code BeanDefinitionBuilder} used to construct a {@link GenericBeanDefinition}.

spring-beans/src/main/java/org/springframework/beans/factory/support/BeanDefinitionReaderUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 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.
@@ -35,7 +35,7 @@ import org.springframework.util.StringUtils;
  * @see PropertiesBeanDefinitionReader
  * @see org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader
  */
-public class BeanDefinitionReaderUtils {
+public final class BeanDefinitionReaderUtils {
 
 	/**
 	 * Separator for generated bean names. If a class name or parent name is not
@@ -44,6 +44,10 @@ public class BeanDefinitionReaderUtils {
 	public static final String GENERATED_BEAN_NAME_SEPARATOR = BeanFactoryUtils.GENERATED_BEAN_NAME_SEPARATOR;
 
 
+	private BeanDefinitionReaderUtils() {
+	}
+
+
 	/**
 	 * Create a new GenericBeanDefinition for the given parent name and class name,
 	 * eagerly loading the bean class if a ClassLoader has been specified.