Use Collections.emptyIterator instead of grabbing the iterator from an empty list.

Resolves #1327.

Author: hduelme

spring-ws-core/src/main/java/org/springframework/ws/transport/http/ClientHttpRequestConnection.java

@@ -98,7 +98,7 @@ public Iterator<String> getResponseHeaderNames() throws IOException {
 	@Override
 	public Iterator<String> getResponseHeaders(String name) throws IOException {
 		List<String> headers = response.getHeaders().get(name);
-		return headers != null ? headers.iterator() : Collections.<String> emptyList().iterator();
+		return headers != null ? headers.iterator() : Collections.emptyIterator();
 	}
 
 	@Override

spring-ws-core/src/main/java/org/springframework/ws/transport/http/HttpUrlConnection.java

@@ -132,7 +132,7 @@ public Iterator<String> getResponseHeaders(String name) throws IOException {
 		List<String> headerValues = headersListMappedByLowerCaseName.get(name.toLowerCase());
 
 		if (headerValues == null) {
-			return Collections.<String> emptyList().iterator();
+			return Collections.emptyIterator();
 		} else {
 			return headerValues.iterator();
 		}

spring-ws-support/src/main/java/org/springframework/ws/transport/http/HttpExchangeConnection.java

@@ -109,7 +109,7 @@ public Iterator<String> getRequestHeaderNames() throws IOException {
 	@Override
 	public Iterator<String> getRequestHeaders(String name) throws IOException {
 		List<String> headers = httpExchange.getRequestHeaders().get(name);
-		return headers != null ? headers.iterator() : Collections.<String> emptyList().iterator();
+		return headers != null ? headers.iterator() : Collections.emptyIterator();
 	}
 
 	@Override

spring-ws-support/src/main/java/org/springframework/ws/transport/jms/support/JmsTransportUtils.java

@@ -154,7 +154,7 @@ public static Iterator<String> getHeaders(Message message, String name) throws J
 		if (value != null) {
 			return Collections.singletonList(value).iterator();
 		} else {
-			return Collections.<String> emptyList().iterator();
+			return Collections.emptyIterator();
 		}
 	}
 

spring-ws-support/src/main/java/org/springframework/ws/transport/xmpp/support/XmppTransportUtils.java

@@ -74,7 +74,7 @@ public static Iterator<String> getHeaders(Message message, String name) {
 		if (value != null) {
 			return Collections.singletonList(value).iterator();
 		} else {
-			return Collections.<String> emptyList().iterator();
+			return Collections.emptyIterator();
 		}
 	}