Consistent use of Collection.toArray with zero-sized array argument

Includes consistent use of ClassUtils.toClassArray (as non-null variant)

Issue: SPR-16523

Author: jhoeller

spring-aop/src/main/java/org/springframework/aop/config/ConfigBeanDefinitionParser.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.
@@ -253,8 +253,8 @@ private AspectComponentDefinition createAspectComponentDefinition(
 			Element aspectElement, String aspectId, List<BeanDefinition> beanDefs,
 			List<BeanReference> beanRefs, ParserContext parserContext) {
 
-		BeanDefinition[] beanDefArray = beanDefs.toArray(new BeanDefinition[beanDefs.size()]);
-		BeanReference[] beanRefArray = beanRefs.toArray(new BeanReference[beanRefs.size()]);
+		BeanDefinition[] beanDefArray = beanDefs.toArray(new BeanDefinition[0]);
+		BeanReference[] beanRefArray = beanRefs.toArray(new BeanReference[0]);
 		Object source = parserContext.extractSource(aspectElement);
 		return new AspectComponentDefinition(aspectId, beanDefArray, beanRefArray, source);
 	}

spring-aop/src/main/java/org/springframework/aop/framework/AdvisedSupport.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.
@@ -228,7 +228,7 @@ public boolean removeInterface(Class<?> intf) {
 
 	@Override
 	public Class<?>[] getProxiedInterfaces() {
-		return this.interfaces.toArray(new Class<?>[this.interfaces.size()]);
+		return ClassUtils.toClassArray(this.interfaces);
 	}
 
 	@Override
@@ -372,7 +372,7 @@ private void addAdvisorInternal(int pos, Advisor advisor) throws AopConfigExcept
 	 * Bring the array up to date with the list.
 	 */
 	protected final void updateAdvisorArray() {
-		this.advisorArray = this.advisors.toArray(new Advisor[this.advisors.size()]);
+		this.advisorArray = this.advisors.toArray(new Advisor[0]);
 	}
 
 	/**

spring-aop/src/main/java/org/springframework/aop/framework/adapter/DefaultAdvisorAdapterRegistry.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.
@@ -90,7 +90,7 @@ public MethodInterceptor[] getInterceptors(Advisor advisor) throws UnknownAdvice
 		if (interceptors.isEmpty()) {
 			throw new UnknownAdviceTypeException(advisor.getAdvice());
 		}
-		return interceptors.toArray(new MethodInterceptor[interceptors.size()]);
+		return interceptors.toArray(new MethodInterceptor[0]);
 	}
 
 	@Override

spring-aop/src/main/java/org/springframework/aop/framework/autoproxy/AbstractAutoProxyCreator.java

@@ -554,7 +554,7 @@ private Advisor[] resolveInterceptorNames() {
 				advisors.add(this.advisorAdapterRegistry.wrap(next));
 			}
 		}
-		return advisors.toArray(new Advisor[advisors.size()]);
+		return advisors.toArray(new Advisor[0]);
 	}
 
 	/**

spring-aop/src/main/java/org/springframework/aop/support/DefaultIntroductionAdvisor.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.
@@ -105,7 +105,7 @@ public void addInterface(Class<?> intf) {
 
 	@Override
 	public Class<?>[] getInterfaces() {
-		return this.interfaces.toArray(new Class<?>[this.interfaces.size()]);
+		return ClassUtils.toClassArray(this.interfaces);
 	}
 
 	@Override

spring-aop/src/main/java/org/springframework/aop/support/IntroductionInfoSupport.java

@@ -61,7 +61,7 @@ public void suppressInterface(Class<?> intf) {
 
 	@Override
 	public Class<?>[] getInterfaces() {
-		return this.publishedInterfaces.toArray(new Class<?>[this.publishedInterfaces.size()]);
+		return ClassUtils.toClassArray(this.publishedInterfaces);
 	}
 
 	/**

spring-beans/src/main/java/org/springframework/beans/AbstractPropertyAccessor.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.
@@ -118,8 +118,7 @@ public void setPropertyValues(PropertyValues pvs, boolean ignoreUnknown, boolean
 
 		// If we encountered individual exceptions, throw the composite exception.
 		if (propertyAccessExceptions != null) {
-			PropertyAccessException[] paeArray =
-					propertyAccessExceptions.toArray(new PropertyAccessException[propertyAccessExceptions.size()]);
+			PropertyAccessException[] paeArray = propertyAccessExceptions.toArray(new PropertyAccessException[0]);
 			throw new PropertyBatchUpdateException(paeArray);
 		}
 	}

spring-beans/src/main/java/org/springframework/beans/ExtendedBeanInfo.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.
@@ -220,7 +220,7 @@ private String propertyNameFor(Method method) {
 	 */
 	@Override
 	public PropertyDescriptor[] getPropertyDescriptors() {
-		return this.propertyDescriptors.toArray(new PropertyDescriptor[this.propertyDescriptors.size()]);
+		return this.propertyDescriptors.toArray(new PropertyDescriptor[0]);
 	}
 
 	@Override

spring-beans/src/main/java/org/springframework/beans/MutablePropertyValues.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.
@@ -246,7 +246,7 @@ public void removePropertyValue(String propertyName) {
 
 	@Override
 	public PropertyValue[] getPropertyValues() {
-		return this.propertyValueList.toArray(new PropertyValue[this.propertyValueList.size()]);
+		return this.propertyValueList.toArray(new PropertyValue[0]);
 	}
 
 	@Override

spring-beans/src/main/java/org/springframework/beans/factory/BeanCreationException.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.
@@ -149,7 +149,7 @@ public Throwable[] getRelatedCauses() {
 		if (this.relatedCauses == null) {
 			return null;
 		}
-		return this.relatedCauses.toArray(new Throwable[this.relatedCauses.size()]);
+		return this.relatedCauses.toArray(new Throwable[0]);
 	}