XmlOptionsFactoryBean initializes empty XmlOptions by default and uses efficient entrySet iteration

Issue: SPR-12383

spring-oxm/src/main/java/org/springframework/oxm/xmlbeans/XmlOptionsFactoryBean.java

 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2014 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.
@@ -30,6 +30,7 @@ import org.springframework.beans.factory.FactoryBean;
  * in the {@link XmlBeansMarshaller}.
  *
  * @author Arjen Poutsma
+ * @author Juergen Hoeller
  * @since 3.0
  * @see XmlOptions
  * @see #setOptions(java.util.Map)
@@ -37,7 +38,7 @@ import org.springframework.beans.factory.FactoryBean;
  */
 public class XmlOptionsFactoryBean implements FactoryBean<XmlOptions> {
 
-	private XmlOptions xmlOptions;
+	private XmlOptions xmlOptions = new XmlOptions();
 
 
 	/**
@@ -51,8 +52,8 @@ public class XmlOptionsFactoryBean implements FactoryBean<XmlOptions> {
 	public void setOptions(Map<String, ?> optionsMap) {
 		this.xmlOptions = new XmlOptions();
 		if (optionsMap != null) {
-			for (String option : optionsMap.keySet()) {
-				this.xmlOptions.put(option, optionsMap.get(option));
+			for (Map.Entry<String, ?> option : optionsMap.entrySet()) {
+				this.xmlOptions.put(option.getKey(), option.getValue());
 			}
 		}
 	}