diff --git a/src/ol/control/fullscreencontrol.js b/src/ol/control/fullscreencontrol.js
index fbd8b7fa61..b085409540 100644
--- a/src/ol/control/fullscreencontrol.js
+++ b/src/ol/control/fullscreencontrol.js
@@ -114,11 +114,9 @@ ol.control.FullScreen.prototype.handleFullScreen_ = function() {
     goog.dom.fullscreen.exitFullScreen();
   } else {
     var target = map.getTarget();
-    goog.asserts.assert(goog.isDefAndNotNull(target),
-        'target should be defined');
+    goog.asserts.assert(target, 'target should be defined');
     var element = goog.dom.getElement(target);
-    goog.asserts.assert(goog.isDefAndNotNull(element),
-        'element should be defined');
+    goog.asserts.assert(element, 'element should be defined');
     if (this.keys_) {
       goog.dom.fullscreen.requestFullScreenWithKeys(element);
     } else {
diff --git a/src/ol/control/zoomslidercontrol.js b/src/ol/control/zoomslidercontrol.js
index d15c8781d8..a98342bd63 100644
--- a/src/ol/control/zoomslidercontrol.js
+++ b/src/ol/control/zoomslidercontrol.js
@@ -182,7 +182,7 @@ ol.control.ZoomSlider.render = function(mapEvent) {
   if (goog.isNull(mapEvent.frameState)) {
     return;
   }
-  goog.asserts.assert(goog.isDefAndNotNull(mapEvent.frameState.viewState),
+  goog.asserts.assert(mapEvent.frameState.viewState,
       'viewState should be defined');
   if (!this.sliderInitialized_) {
     this.initSlider_();
diff --git a/src/ol/format/esrijsonformat.js b/src/ol/format/esrijsonformat.js
index 74affb0fe7..2863816334 100644
--- a/src/ol/format/esrijsonformat.js
+++ b/src/ol/format/esrijsonformat.js
@@ -60,15 +60,15 @@ ol.format.EsriJSON.readGeometry_ = function(object, opt_options) {
   var type;
   if (goog.isNumber(object.x) && goog.isNumber(object.y)) {
     type = ol.geom.GeometryType.POINT;
-  } else if (goog.isDefAndNotNull(object.points)) {
+  } else if (object.points) {
     type = ol.geom.GeometryType.MULTI_POINT;
-  } else if (goog.isDefAndNotNull(object.paths)) {
+  } else if (object.paths) {
     if (object.paths.length === 1) {
       type = ol.geom.GeometryType.LINE_STRING;
     } else {
       type = ol.geom.GeometryType.MULTI_LINE_STRING;
     }
-  } else if (goog.isDefAndNotNull(object.rings)) {
+  } else if (object.rings) {
     var layout = ol.format.EsriJSON.getGeometryLayout_(object);
     var rings = ol.format.EsriJSON.convertRings_(object.rings, layout);
     object = /** @type {EsriJSONGeometry} */(goog.object.clone(object));
@@ -149,13 +149,13 @@ ol.format.EsriJSON.readPointGeometry_ = function(object) {
   goog.asserts.assert(goog.isNumber(object.x), 'object.x should be number');
   goog.asserts.assert(goog.isNumber(object.y), 'object.y should be number');
   var point;
-  if (goog.isDefAndNotNull(object.m) && goog.isDefAndNotNull(object.z)) {
+  if (object.m !== undefined && object.z !== undefined) {
     point = new ol.geom.Point([object.x, object.y, object.z, object.m],
         ol.geom.GeometryLayout.XYZM);
-  } else if (goog.isDefAndNotNull(object.z)) {
+  } else if (object.z !== undefined) {
     point = new ol.geom.Point([object.x, object.y, object.z],
         ol.geom.GeometryLayout.XYZ);
-  } else if (goog.isDefAndNotNull(object.m)) {
+  } else if (object.m !== undefined) {
     point = new ol.geom.Point([object.x, object.y, object.m],
         ol.geom.GeometryLayout.XYM);
   } else {
@@ -219,8 +219,7 @@ ol.format.EsriJSON.getGeometryLayout_ = function(object) {
  * @return {ol.geom.Geometry} MultiPoint.
  */
 ol.format.EsriJSON.readMultiPointGeometry_ = function(object) {
-  goog.asserts.assert(goog.isDefAndNotNull(object.points),
-      'object.points should be defined');
+  goog.asserts.assert(object.points, 'object.points should be defined');
   var layout = ol.format.EsriJSON.getGeometryLayout_(object);
   return new ol.geom.MultiPoint(object.points, layout);
 };
@@ -232,7 +231,7 @@ ol.format.EsriJSON.readMultiPointGeometry_ = function(object) {
  * @return {ol.geom.Geometry} MultiPolygon.
  */
 ol.format.EsriJSON.readMultiPolygonGeometry_ = function(object) {
-  goog.asserts.assert(goog.isDefAndNotNull(object.rings));
+  goog.asserts.assert(object.rings);
   goog.asserts.assert(object.rings.length > 1,
       'object.rings should have length larger than 1');
   var layout = ol.format.EsriJSON.getGeometryLayout_(object);
@@ -248,7 +247,7 @@ ol.format.EsriJSON.readMultiPolygonGeometry_ = function(object) {
  * @return {ol.geom.Geometry} Polygon.
  */
 ol.format.EsriJSON.readPolygonGeometry_ = function(object) {
-  goog.asserts.assert(goog.isDefAndNotNull(object.rings));
+  goog.asserts.assert(object.rings);
   var layout = ol.format.EsriJSON.getGeometryLayout_(object);
   return new ol.geom.Polygon(object.rings, layout);
 };
@@ -483,10 +482,9 @@ ol.format.EsriJSON.prototype.readFeatures;
 ol.format.EsriJSON.prototype.readFeatureFromObject = function(
     object, opt_options) {
   var esriJSONFeature = /** @type {EsriJSONFeature} */ (object);
-  goog.asserts.assert(goog.isDefAndNotNull(esriJSONFeature.geometry) ||
-      goog.isDefAndNotNull(esriJSONFeature.compressedGeometry) ||
-      goog.isDefAndNotNull(esriJSONFeature.attributes),
-      'geometry, compressedGeometry or attributes should be defined');
+  goog.asserts.assert(esriJSONFeature.geometry ||
+      esriJSONFeature.attributes,
+      'geometry or attributes should be defined');
   var geometry = ol.format.EsriJSON.readGeometry_(esriJSONFeature.geometry,
       opt_options);
   var feature = new ol.Feature();
@@ -516,7 +514,7 @@ ol.format.EsriJSON.prototype.readFeaturesFromObject = function(
     object, opt_options) {
   var esriJSONObject = /** @type {EsriJSONObject} */ (object);
   var options = opt_options ? opt_options : {};
-  if (goog.isDefAndNotNull(esriJSONObject.features)) {
+  if (esriJSONObject.features) {
     var esriJSONFeatureCollection = /** @type {EsriJSONFeatureCollection} */
         (object);
     /** @type {Array.<ol.Feature>} */
@@ -573,8 +571,7 @@ ol.format.EsriJSON.prototype.readProjection;
  */
 ol.format.EsriJSON.prototype.readProjectionFromObject = function(object) {
   var esriJSONObject = /** @type {EsriJSONObject} */ (object);
-  if (goog.isDefAndNotNull(esriJSONObject.spatialReference) &&
-      goog.isDefAndNotNull(esriJSONObject.spatialReference.wkid)) {
+  if (esriJSONObject.spatialReference && esriJSONObject.spatialReference.wkid) {
     var crs = esriJSONObject.spatialReference.wkid;
     return ol.proj.get('EPSG:' + crs);
   } else {
diff --git a/src/ol/format/featureformat.js b/src/ol/format/featureformat.js
index bb3425e209..6f6f58aa1a 100644
--- a/src/ol/format/featureformat.js
+++ b/src/ol/format/featureformat.js
@@ -67,7 +67,7 @@ ol.format.Feature.prototype.adaptOptions = function(options) {
   if (options) {
     updatedOptions = {
       featureProjection: options.featureProjection,
-      dataProjection: goog.isDefAndNotNull(options.dataProjection) ?
+      dataProjection: options.dataProjection ?
           options.dataProjection : this.defaultDataProjection,
       rightHanded: options.rightHanded
     };
diff --git a/src/ol/format/geojsonformat.js b/src/ol/format/geojsonformat.js
index 317f9600c9..cb6db7aa0c 100644
--- a/src/ol/format/geojsonformat.js
+++ b/src/ol/format/geojsonformat.js
@@ -38,7 +38,7 @@ ol.format.GeoJSON = function(opt_options) {
    * @inheritDoc
    */
   this.defaultDataProjection = ol.proj.get(
-      goog.isDefAndNotNull(options.defaultDataProjection) ?
+      options.defaultDataProjection ?
           options.defaultDataProjection : 'EPSG:4326');
 
 
diff --git a/src/ol/format/gml/gml3format.js b/src/ol/format/gml/gml3format.js
index a63684dda9..b908744af3 100644
--- a/src/ol/format/gml/gml3format.js
+++ b/src/ol/format/gml/gml3format.js
@@ -804,7 +804,7 @@ ol.format.GML3.prototype.writeSurfaceOrPolygon_ =
   var context = objectStack[objectStack.length - 1];
   goog.asserts.assert(goog.isObject(context), 'context should be an Object');
   var srsName = context['srsName'];
-  if (node.nodeName !== 'PolygonPatch' && goog.isDefAndNotNull(srsName)) {
+  if (node.nodeName !== 'PolygonPatch' && srsName) {
     node.setAttribute('srsName', srsName);
   }
   if (node.nodeName === 'Polygon' || node.nodeName === 'PolygonPatch') {
@@ -834,8 +834,7 @@ ol.format.GML3.prototype.writeCurveOrLineString_ =
   var context = objectStack[objectStack.length - 1];
   goog.asserts.assert(goog.isObject(context), 'context should be an Object');
   var srsName = context['srsName'];
-  if (node.nodeName !== 'LineStringSegment' &&
-      goog.isDefAndNotNull(srsName)) {
+  if (node.nodeName !== 'LineStringSegment' && srsName) {
     node.setAttribute('srsName', srsName);
   }
   if (node.nodeName === 'LineString' ||
diff --git a/src/ol/format/gml/gmlbaseformat.js b/src/ol/format/gml/gmlbaseformat.js
index 8e50f6d1f1..5f7cc9826a 100644
--- a/src/ol/format/gml/gmlbaseformat.js
+++ b/src/ol/format/gml/gmlbaseformat.js
@@ -116,7 +116,7 @@ ol.format.GMLBase.prototype.readFeaturesInternal = function(node, objectStack) {
     var featureType = context['featureType'];
     var featureNS = context['featureNS'];
     var i, ii, prefix = 'p', defaultPrefix = 'p0';
-    if (!featureType && goog.isDefAndNotNull(node.childNodes)) {
+    if (!featureType && node.childNodes) {
       featureType = [], featureNS = {};
       for (i = 0, ii = node.childNodes.length; i < ii; ++i) {
         var child = node.childNodes[i];
diff --git a/src/ol/format/kmlformat.js b/src/ol/format/kmlformat.js
index 79c9d5f2e3..6c870684a1 100644
--- a/src/ol/format/kmlformat.js
+++ b/src/ol/format/kmlformat.js
@@ -394,7 +394,7 @@ ol.format.KML.readFlatCoordinates_ = function(node) {
  */
 ol.format.KML.readStyleUrl_ = function(node) {
   var s = goog.string.trim(ol.xml.getAllTextContent(node, false));
-  if (goog.isDefAndNotNull(node.baseURI)) {
+  if (node.baseURI) {
     return goog.Uri.resolve(node.baseURI, s).toString();
   } else {
     return s;
@@ -410,7 +410,7 @@ ol.format.KML.readStyleUrl_ = function(node) {
  */
 ol.format.KML.readURI_ = function(node) {
   var s = ol.xml.getAllTextContent(node, false);
-  if (goog.isDefAndNotNull(node.baseURI)) {
+  if (node.baseURI) {
     return goog.Uri.resolve(node.baseURI, goog.string.trim(s)).toString();
   } else {
     return goog.string.trim(s);
@@ -980,8 +980,7 @@ ol.format.KML.readPolygon_ = function(node, objectStack) {
   var flatLinearRings = ol.xml.pushParseAndPop(
       /** @type {Array.<Array.<number>>} */ ([null]),
       ol.format.KML.FLAT_LINEAR_RINGS_PARSERS_, node, objectStack);
-  if (goog.isDefAndNotNull(flatLinearRings) &&
-      !goog.isNull(flatLinearRings[0])) {
+  if (flatLinearRings && !goog.isNull(flatLinearRings[0])) {
     var polygon = new ol.geom.Polygon(null);
     var flatCoordinates = flatLinearRings[0];
     var ends = [flatCoordinates.length];
@@ -1721,7 +1720,7 @@ ol.format.KML.prototype.readSharedStyle_ = function(node, objectStack) {
     var style = ol.format.KML.readStyle_(node, objectStack);
     if (style) {
       var styleUri;
-      if (goog.isDefAndNotNull(node.baseURI)) {
+      if (node.baseURI) {
         styleUri = goog.Uri.resolve(node.baseURI, '#' + id).toString();
       } else {
         styleUri = '#' + id;
@@ -1751,7 +1750,7 @@ ol.format.KML.prototype.readSharedStyleMap_ = function(node, objectStack) {
     return;
   }
   var styleUri;
-  if (goog.isDefAndNotNull(node.baseURI)) {
+  if (node.baseURI) {
     styleUri = goog.Uri.resolve(node.baseURI, '#' + id).toString();
   } else {
     styleUri = '#' + id;
@@ -2267,7 +2266,7 @@ ol.format.KML.writePlacemark_ = function(node, feature, objectStack) {
   var /** @type {ol.xml.NodeStackItem} */ context = {node: node};
 
   // set id
-  if (goog.isDefAndNotNull(feature.getId())) {
+  if (feature.getId()) {
     node.setAttribute('id', feature.getId());
   }
 
diff --git a/src/ol/format/topojsonformat.js b/src/ol/format/topojsonformat.js
index d8a30b34e5..ae275793cd 100644
--- a/src/ol/format/topojsonformat.js
+++ b/src/ol/format/topojsonformat.js
@@ -34,7 +34,7 @@ ol.format.TopoJSON = function(opt_options) {
    * @inheritDoc
    */
   this.defaultDataProjection = ol.proj.get(
-      goog.isDefAndNotNull(options.defaultDataProjection) ?
+      options.defaultDataProjection ?
           options.defaultDataProjection : 'EPSG:4326');
 
 };
diff --git a/src/ol/format/wfsformat.js b/src/ol/format/wfsformat.js
index 19c316a329..63dd77bfb1 100644
--- a/src/ol/format/wfsformat.js
+++ b/src/ol/format/wfsformat.js
@@ -475,7 +475,7 @@ ol.format.WFS.writeProperty_ = function(node, pair, objectStack) {
   var name = ol.xml.createElementNS('http://www.opengis.net/wfs', 'Name');
   node.appendChild(name);
   ol.format.XSD.writeStringTextNode(name, pair.name);
-  if (goog.isDefAndNotNull(pair.value)) {
+  if (pair.value !== undefined && pair.value !== null) {
     var value = ol.xml.createElementNS('http://www.opengis.net/wfs', 'Value');
     node.appendChild(value);
     if (pair.value instanceof ol.geom.Geometry) {
@@ -768,8 +768,8 @@ ol.format.WFS.prototype.readProjectionFromNode = function(node) {
   goog.asserts.assert(node.localName == 'FeatureCollection',
       'localName should be FeatureCollection');
 
-  if (goog.isDefAndNotNull(node.firstElementChild) &&
-      goog.isDefAndNotNull(node.firstElementChild.firstElementChild)) {
+  if (node.firstElementChild &&
+      node.firstElementChild.firstElementChild) {
     node = node.firstElementChild.firstElementChild;
     for (var n = node.firstElementChild; !goog.isNull(n);
         n = n.nextElementSibling) {
diff --git a/src/ol/interaction/drawinteraction.js b/src/ol/interaction/drawinteraction.js
index a1cadd6e08..a0f1ff7c4c 100644
--- a/src/ol/interaction/drawinteraction.js
+++ b/src/ol/interaction/drawinteraction.js
@@ -723,8 +723,7 @@ ol.interaction.Draw.prototype.extend = function(feature) {
   var geometry = feature.getGeometry();
   goog.asserts.assert(this.mode_ == ol.interaction.DrawMode.LINE_STRING,
       'interaction mode must be "line"');
-  goog.asserts.assert(goog.isDefAndNotNull(geometry),
-      'feature must have a geometry');
+  goog.asserts.assert(geometry, 'feature must have a geometry');
   goog.asserts.assert(geometry.getType() == ol.geom.GeometryType.LINE_STRING,
       'feature geometry must be a line string');
   var lineString = /** @type {ol.geom.LineString} */ (geometry);
diff --git a/src/ol/map.js b/src/ol/map.js
index 5ababe54b6..f57a488922 100644
--- a/src/ol/map.js
+++ b/src/ol/map.js
@@ -1151,7 +1151,7 @@ ol.Map.prototype.isDef = function() {
     return false;
   }
   var size = this.getSize();
-  if (!goog.isDefAndNotNull(size) || size[0] <= 0 || size[1] <= 0) {
+  if (!size || size[0] <= 0 || size[1] <= 0) {
     return false;
   }
   var view = this.getView();
diff --git a/src/ol/overlay.js b/src/ol/overlay.js
index 7e60413223..1d85f00566 100644
--- a/src/ol/overlay.js
+++ b/src/ol/overlay.js
@@ -372,8 +372,7 @@ ol.Overlay.prototype.panIntoView_ = function() {
 
   var mapRect = this.getRect_(map.getTargetElement(), map.getSize());
   var element = this.getElement();
-  goog.asserts.assert(goog.isDefAndNotNull(element),
-      'element should be defined');
+  goog.asserts.assert(element, 'element should be defined');
   var overlayRect = this.getRect_(element,
       [ol.dom.outerWidth(element), ol.dom.outerHeight(element)]);
 
@@ -428,8 +427,7 @@ ol.Overlay.prototype.panIntoView_ = function() {
  * @private
  */
 ol.Overlay.prototype.getRect_ = function(element, size) {
-  goog.asserts.assert(goog.isDefAndNotNull(element),
-      'element should be defined');
+  goog.asserts.assert(element, 'element should be defined');
   goog.asserts.assert(size !== undefined, 'size should be defined');
 
   var offset = goog.style.getPageOffset(element);
diff --git a/src/ol/render/box.js b/src/ol/render/box.js
index 13b2ac4044..59bc2aae9a 100644
--- a/src/ol/render/box.js
+++ b/src/ol/render/box.js
@@ -96,8 +96,7 @@ ol.render.Box.prototype.disposeInternal = function() {
  */
 ol.render.Box.prototype.handleMapPostCompose_ = function(event) {
   var geometry = this.geometry_;
-  goog.asserts.assert(goog.isDefAndNotNull(geometry),
-      'geometry should be defined');
+  goog.asserts.assert(geometry, 'geometry should be defined');
   var style = this.style_;
   goog.asserts.assert(!goog.isNull(style), 'style should not be null');
   // use drawAsync(Infinity) to draw above everything
diff --git a/src/ol/render/canvas/canvasimmediate.js b/src/ol/render/canvas/canvasimmediate.js
index 6f30e5820f..7706ab0227 100644
--- a/src/ol/render/canvas/canvasimmediate.js
+++ b/src/ol/render/canvas/canvasimmediate.js
@@ -480,7 +480,7 @@ ol.render.canvas.Immediate.prototype.drawCircleGeometry =
  */
 ol.render.canvas.Immediate.prototype.drawFeature = function(feature, style) {
   var geometry = style.getGeometryFunction()(feature);
-  if (!goog.isDefAndNotNull(geometry) ||
+  if (!geometry ||
       !ol.extent.intersects(this.extent_, geometry.getExtent())) {
     return;
   }
@@ -874,7 +874,7 @@ ol.render.canvas.Immediate.prototype.setFillStrokeStyle =
     this.strokeState_ = {
       lineCap: strokeStyleLineCap !== undefined ?
           strokeStyleLineCap : ol.render.canvas.defaultLineCap,
-      lineDash: goog.isDefAndNotNull(strokeStyleLineDash) ?
+      lineDash: strokeStyleLineDash ?
           strokeStyleLineDash : ol.render.canvas.defaultLineDash,
       lineJoin: strokeStyleLineJoin !== undefined ?
           strokeStyleLineJoin : ol.render.canvas.defaultLineJoin,
@@ -963,7 +963,7 @@ ol.render.canvas.Immediate.prototype.setTextStyle = function(textStyle) {
       this.textStrokeState_ = {
         lineCap: textStrokeStyleLineCap !== undefined ?
             textStrokeStyleLineCap : ol.render.canvas.defaultLineCap,
-        lineDash: goog.isDefAndNotNull(textStrokeStyleLineDash) ?
+        lineDash: textStrokeStyleLineDash ?
             textStrokeStyleLineDash : ol.render.canvas.defaultLineDash,
         lineJoin: textStrokeStyleLineJoin !== undefined ?
             textStrokeStyleLineJoin : ol.render.canvas.defaultLineJoin,
diff --git a/src/ol/render/canvas/canvasreplay.js b/src/ol/render/canvas/canvasreplay.js
index 7948cc3edb..51e8e693ef 100644
--- a/src/ol/render/canvas/canvasreplay.js
+++ b/src/ol/render/canvas/canvasreplay.js
@@ -259,7 +259,7 @@ ol.render.canvas.Replay.prototype.replay_ = function(
         feature = /** @type {ol.Feature} */ (instruction[1]);
         var featureUid = goog.getUid(feature).toString();
         if (skippedFeaturesHash[featureUid] !== undefined ||
-            !goog.isDefAndNotNull(feature.getGeometry())) {
+            !feature.getGeometry()) {
           i = /** @type {number} */ (instruction[2]);
         } else if (opt_hitExtent !== undefined && !ol.extent.intersects(
             /** @type {Array<number>} */ (opt_hitExtent),
@@ -1728,7 +1728,7 @@ ol.render.canvas.TextReplay.prototype.setTextStyle = function(textStyle) {
       var textStrokeStyleMiterLimit = textStrokeStyle.getMiterLimit();
       var lineCap = textStrokeStyleLineCap !== undefined ?
           textStrokeStyleLineCap : ol.render.canvas.defaultLineCap;
-      var lineDash = goog.isDefAndNotNull(textStrokeStyleLineDash) ?
+      var lineDash = textStrokeStyleLineDash ?
           textStrokeStyleLineDash.slice() : ol.render.canvas.defaultLineDash;
       var lineJoin = textStrokeStyleLineJoin !== undefined ?
           textStrokeStyleLineJoin : ol.render.canvas.defaultLineJoin;
diff --git a/src/ol/render/webgl/webglimmediate.js b/src/ol/render/webgl/webglimmediate.js
index ae38988c94..d337ae5214 100644
--- a/src/ol/render/webgl/webglimmediate.js
+++ b/src/ol/render/webgl/webglimmediate.js
@@ -126,7 +126,7 @@ ol.render.webgl.Immediate.prototype.drawCircleGeometry =
  */
 ol.render.webgl.Immediate.prototype.drawFeature = function(feature, style) {
   var geometry = style.getGeometryFunction()(feature);
-  if (!goog.isDefAndNotNull(geometry) ||
+  if (!geometry ||
       !ol.extent.intersects(this.extent_, geometry.getExtent())) {
     return;
   }
diff --git a/src/ol/render/webgl/webglreplay.js b/src/ol/render/webgl/webglreplay.js
index 3bffb7c0b4..07d4090171 100644
--- a/src/ol/render/webgl/webglreplay.js
+++ b/src/ol/render/webgl/webglreplay.js
@@ -821,7 +821,7 @@ ol.render.webgl.ImageReplay.prototype.drawHitDetectionReplayOneByOne_ =
       featureUid = goog.getUid(feature).toString();
 
       if (skippedFeaturesHash[featureUid] === undefined &&
-          goog.isDefAndNotNull(feature.getGeometry()) &&
+          feature.getGeometry() &&
           (opt_hitExtent === undefined || ol.extent.intersects(
               /** @type {Array<number>} */ (opt_hitExtent),
               feature.getGeometry().getExtent()))) {
diff --git a/src/ol/source/tilearcgisrestsource.js b/src/ol/source/tilearcgisrestsource.js
index 663574695c..97b031056c 100644
--- a/src/ol/source/tilearcgisrestsource.js
+++ b/src/ol/source/tilearcgisrestsource.js
@@ -56,7 +56,7 @@ ol.source.TileArcGISRest = function(opt_options) {
    * @private
    * @type {!Array.<string>}
    */
-  this.urls_ = goog.isDefAndNotNull(urls) ? urls : [];
+  this.urls_ = urls || [];
 
   /**
    * @private
@@ -184,7 +184,7 @@ ol.source.TileArcGISRest.prototype.setUrl = function(url) {
  * @api stable
  */
 ol.source.TileArcGISRest.prototype.setUrls = function(urls) {
-  this.urls_ = goog.isDefAndNotNull(urls) ? urls : [];
+  this.urls_ = urls || [];
   this.changed();
 };