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

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

Issue: SPR-16523

spring-jms/src/main/java/org/springframework/jms/connection/CachingConnectionFactory.java

@@ -41,6 +41,7 @@ import javax.jms.TopicSession;
 
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.ObjectUtils;
 
 /**
@@ -254,10 +255,8 @@ public class CachingConnectionFactory extends SingleConnectionFactory {
 		if (target instanceof TopicSession) {
 			classes.add(TopicSession.class);
 		}
-		return (Session) Proxy.newProxyInstance(
-				SessionProxy.class.getClassLoader(),
-				classes.toArray(new Class<?>[classes.size()]),
-				new CachedSessionInvocationHandler(target, sessionList));
+		return (Session) Proxy.newProxyInstance(SessionProxy.class.getClassLoader(),
+				ClassUtils.toClassArray(classes), new CachedSessionInvocationHandler(target, sessionList));
 	}
 
 

spring-jms/src/main/java/org/springframework/jms/connection/ChainedExceptionListener.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.
@@ -48,7 +48,7 @@ public class ChainedExceptionListener implements ExceptionListener {
 	 * Return all registered ExceptionListener delegates (as array).
 	 */
 	public final ExceptionListener[] getDelegates() {
-		return this.delegates.toArray(new ExceptionListener[this.delegates.size()]);
+		return this.delegates.toArray(new ExceptionListener[0]);
 	}
 
 

spring-jms/src/main/java/org/springframework/jms/connection/SingleConnectionFactory.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.
@@ -42,6 +42,7 @@ import org.springframework.beans.factory.DisposableBean;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
 
 /**
  * A JMS ConnectionFactory adapter that returns the same Connection
@@ -519,10 +520,8 @@ public class SingleConnectionFactory implements ConnectionFactory, QueueConnecti
 		if (target instanceof TopicConnection) {
 			classes.add(TopicConnection.class);
 		}
-		return (Connection) Proxy.newProxyInstance(
-				Connection.class.getClassLoader(),
-				classes.toArray(new Class<?>[classes.size()]),
-				new SharedConnectionInvocationHandler());
+		return (Connection) Proxy.newProxyInstance(Connection.class.getClassLoader(),
+				ClassUtils.toClassArray(classes), new SharedConnectionInvocationHandler());
 	}
 
 

spring-jms/src/main/java/org/springframework/jms/connection/TransactionAwareConnectionFactoryProxy.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.
@@ -37,6 +37,7 @@ import javax.jms.TransactionInProgressException;
 
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.ClassUtils;
 
 /**
  * Proxy for a target JMS {@link javax.jms.ConnectionFactory}, adding awareness of
@@ -229,10 +230,8 @@ public class TransactionAwareConnectionFactoryProxy
 		if (target instanceof TopicConnection) {
 			classes.add(TopicConnection.class);
 		}
-		return (Connection) Proxy.newProxyInstance(
-				Connection.class.getClassLoader(),
-				classes.toArray(new Class<?>[classes.size()]),
-				new TransactionAwareConnectionInvocationHandler(target));
+		return (Connection) Proxy.newProxyInstance(Connection.class.getClassLoader(),
+				ClassUtils.toClassArray(classes), new TransactionAwareConnectionInvocationHandler(target));
 	}
 
 
@@ -301,10 +300,8 @@ public class TransactionAwareConnectionFactoryProxy
 			if (target instanceof TopicSession) {
 				classes.add(TopicSession.class);
 			}
-			return (Session) Proxy.newProxyInstance(
-					SessionProxy.class.getClassLoader(),
-					classes.toArray(new Class<?>[classes.size()]),
-					new CloseSuppressingSessionInvocationHandler(target));
+			return (Session) Proxy.newProxyInstance(SessionProxy.class.getClassLoader(),
+					ClassUtils.toClassArray(classes), new CloseSuppressingSessionInvocationHandler(target));
 		}
 	}