diff --git a/src/ol/parser/ogc/sldparser_v1.js b/src/ol/parser/ogc/sldparser_v1.js
index ed9757b038..a1516d8c5a 100644
--- a/src/ol/parser/ogc/sldparser_v1.js
+++ b/src/ol/parser/ogc/sldparser_v1.js
@@ -342,10 +342,10 @@ ol.parser.ogc.SLD_v1 = function() {
     'UserStyle': function(style) {
       var node = this.createElementNS('sld:UserStyle');
       var name = style.getName(), title = style.getTitle();
-      if (!goog.isNull(name)) {
+      if (goog.isDef(name)) {
         this.writeNode('Name', name, null, node);
       }
-      if (!goog.isNull(title)) {
+      if (goog.isDef(title)) {
         this.writeNode('Title', title, null, node);
       }
       // TODO sorting by zIndex
@@ -370,11 +370,12 @@ ol.parser.ogc.SLD_v1 = function() {
     'Rule': function(rule) {
       var node = this.createElementNS('sld:Rule');
       var filter = rule.getFilter();
-      if (!goog.isNull(rule.getName())) {
-        this.writeNode('Name', rule.getName(), null, node);
+      var name = rule.getName(), title = rule.getTitle();
+      if (goog.isDef(name)) {
+        this.writeNode('Name', name, null, node);
       }
-      if (!goog.isNull(rule.getTitle())) {
-        this.writeNode('Title', rule.title, null, node);
+      if (goog.isDef(title)) {
+        this.writeNode('Title', title, null, node);
       }
       if (rule.elseFilter === true) {
         this.writeNode('ElseFilter', null, null, node);
diff --git a/src/ol/style/rule.js b/src/ol/style/rule.js
index 3495422459..d8234de95b 100644
--- a/src/ol/style/rule.js
+++ b/src/ol/style/rule.js
@@ -55,18 +55,18 @@ ol.style.Rule = function(options) {
       options.maxResolution : Infinity;
 
   /**
-   * @type {?string}
+   * @type {string|undefined}
    * @private
    */
   this.name_ = goog.isDef(options.name) ?
-      options.name : null;
+      options.name : undefined;
 
   /**
-   * @type {?string}
+   * @type {string|undefined}
    * @private
    */
   this.title_ = goog.isDef(options.title) ?
-      options.title : null;
+      options.title : undefined;
 
 };
 
@@ -119,7 +119,7 @@ ol.style.Rule.prototype.getMaxResolution = function() {
 
 
 /**
- * @return {?string}
+ * @return {string|undefined}
  */
 ol.style.Rule.prototype.getName = function() {
   return this.name_;
@@ -127,7 +127,7 @@ ol.style.Rule.prototype.getName = function() {
 
 
 /**
- * @return {?string}
+ * @return {string|undefined}
  */
 ol.style.Rule.prototype.getTitle = function() {
   return this.title_;
diff --git a/src/ol/style/style.js b/src/ol/style/style.js
index 224ec2578c..c8d70ef635 100644
--- a/src/ol/style/style.js
+++ b/src/ol/style/style.js
@@ -41,18 +41,18 @@ ol.style.Style = function(options) {
       options.symbolizers : [];
 
   /**
-   * @type {?string}
+   * @type {string|undefined}
    * @private
    */
   this.name_ = goog.isDef(options.name) ?
-      options.name : null;
+      options.name : undefined;
 
   /**
-   * @type {?string}
+   * @type {string|undefined}
    * @private
    */
   this.title_ = goog.isDef(options.title) ?
-      options.title : null;
+      options.title : undefined;
 };
 
 
@@ -247,7 +247,7 @@ ol.style.Style.prototype.getSymbolizers = function() {
 
 
 /**
- * @return {?string}
+ * @return {string|undefined}
  */
 ol.style.Style.prototype.getName = function() {
   return this.name_;
@@ -255,7 +255,7 @@ ol.style.Style.prototype.getName = function() {
 
 
 /**
- * @return {?string}
+ * @return {string|undefined}
  */
 ol.style.Style.prototype.getTitle = function() {
   return this.title_;