diff --git a/platform/lang-api/src/com/intellij/psi/util/PsiTreeUtil.java b/platform/lang-api/src/com/intellij/psi/util/PsiTreeUtil.java
index 0ac05c043156..ff6393c01359 100644
--- a/platform/lang-api/src/com/intellij/psi/util/PsiTreeUtil.java
+++ b/platform/lang-api/src/com/intellij/psi/util/PsiTreeUtil.java
@@ -30,6 +30,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 
 public class PsiTreeUtil {
@@ -465,6 +466,25 @@ public class PsiTreeUtil {
     return processor.toArray();
   }
 
+  @NotNull
+  public static <T extends PsiElement> Collection<T> collectElementsOfType(@Nullable PsiElement element, final @NotNull Class<T> ... classes)  {
+    PsiElementProcessor.CollectFilteredElements<T> processor = new PsiElementProcessor.CollectFilteredElements<T>(new PsiElementFilter() {
+
+      @Override
+      public boolean isAccepted(PsiElement element) {
+        for (Class<T> clazz: classes) {
+          if (clazz.isInstance(element)) {
+            return true;
+          }
+        }
+
+        return false;
+      }
+    });
+    processElements(element, processor);
+    return processor.getCollection();
+  }
+
   public static boolean processElements(@Nullable PsiElement element, @NotNull PsiElementProcessor processor) {
     if (element == null) return true;
     if (!processor.execute(element)) return false;
@@ -740,5 +760,5 @@ public class PsiTreeUtil {
     }
     throw new AssertionError(descendant + " is not a descendant of " + ancestor);
   }
-  
+
 }
diff --git a/platform/util/src/com/intellij/util/containers/CollectionFactory.java b/platform/util/src/com/intellij/util/containers/CollectionFactory.java
index f182b4ab5cb9..66c858f4b8e9 100644
--- a/platform/util/src/com/intellij/util/containers/CollectionFactory.java
+++ b/platform/util/src/com/intellij/util/containers/CollectionFactory.java
@@ -15,6 +15,9 @@
  */
 package com.intellij.util.containers;
 
+import com.google.common.collect.Lists;
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
 import gnu.trove.THashMap;
 import gnu.trove.THashSet;
 import org.jetbrains.annotations.NotNull;
@@ -50,7 +53,7 @@ public class CollectionFactory {
   }
 
   public static <T> ArrayList<T> arrayList() {
-    return new ArrayList<T>();
+    return Lists.newArrayList();
   }
 
   public static <T> ArrayList<T> arrayList(T... elements) {
@@ -80,19 +83,19 @@ public class CollectionFactory {
     return new Stack<T>();
   }
 
-  public static <T> HashSet<T> hashSet() {
-    return new HashSet<T>();
+  public static <T> Set<T> hashSet() {
+    return Sets.newHashSet();
   }
 
-  public static <T, V> HashMap<T, V> hashMap() {
-    return new HashMap<T,V>();
+  public static <T, V> Map<T, V> hashMap() {
+    return Maps.newHashMap();
   }
 
   public static <T, V> LinkedHashMap<T, V> linkedMap() {
-    return new LinkedHashMap<T,V>();
+    return Maps.newLinkedHashMap();
   }
 
   public static <T> LinkedHashSet<T> linkedHashSet() {
-    return new LinkedHashSet<T>();
+    return Sets.newLinkedHashSet();
   }
 }
diff --git a/platform/util/util.iml b/platform/util/util.iml
index 8006db04d27a..d74a166efbe6 100644
--- a/platform/util/util.iml
+++ b/platform/util/util.iml
@@ -17,6 +17,7 @@
     <orderEntry type="library" name="OroMatcher" level="project" />
     <orderEntry type="module" module-name="annotations" exported="" />
     <orderEntry type="library" name="commons-lang" level="project" />
+    <orderEntry type="library" name="Guava" level="project" />
   </component>
   <component name="copyright">
     <Base>
diff --git a/xml/impl/src/com/intellij/ide/structureView/impl/xml/XmlTagTreeElement.java b/xml/impl/src/com/intellij/ide/structureView/impl/xml/XmlTagTreeElement.java
index b14f957f07db..d9430f6a9d8c 100644
--- a/xml/impl/src/com/intellij/ide/structureView/impl/xml/XmlTagTreeElement.java
+++ b/xml/impl/src/com/intellij/ide/structureView/impl/xml/XmlTagTreeElement.java
@@ -20,6 +20,7 @@ import com.intellij.psi.xml.XmlAttribute;
 import com.intellij.psi.xml.XmlTag;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.Collection;
 
@@ -86,7 +87,8 @@ public class XmlTagTreeElement extends AbstractXmlTagTreeElement<XmlTag>{
     return buffer.toString();
   }
 
-  private static String toCanonicalForm(String id) {
+  @Nullable
+  private static String toCanonicalForm(@Nullable String id) {
     if (id != null) {
       id = id.trim();
       if (id.length() == 0) id = null;