diff --git a/java/java-tests/testSrc/com/intellij/psi/TreeIsCorrectAfterDiffReparseTest.java b/java/java-tests/testSrc/com/intellij/psi/TreeIsCorrectAfterDiffReparseTest.java
index b5e1712fbbd6..ef874519d512 100644
--- a/java/java-tests/testSrc/com/intellij/psi/TreeIsCorrectAfterDiffReparseTest.java
+++ b/java/java-tests/testSrc/com/intellij/psi/TreeIsCorrectAfterDiffReparseTest.java
@@ -6,11 +6,12 @@ package com.intellij.psi;
 import com.intellij.openapi.editor.Document;
 import com.intellij.psi.impl.DebugUtil;
 import com.intellij.testFramework.LightCodeInsightTestCase;
+import org.jetbrains.annotations.NonNls;
 
 public class TreeIsCorrectAfterDiffReparseTest extends LightCodeInsightTestCase {
 
   public void testIDEADEV41862() throws Exception {
-    String part1 = "package com.test;\n" +
+    @NonNls String part1 = "package com.test;\n" +
                    "\n" +
                    "\n" +
                    "//------------------------------------------------------------------\n" +
@@ -952,7 +953,7 @@ public class TreeIsCorrectAfterDiffReparseTest extends LightCodeInsightTestCase
                    "\n" +
                    "  ";
 
-    String part2 = "\n" +
+    @NonNls String part2 = "\n" +
                    "  private TransactionStatus getHighestPriorityError(TransactionStatus existingStatus, Message newError) {\n" +
                    "    if(existingStatus == null) {\n" +
                    "      return newError;\n" +
diff --git a/java/testFramework/src/com/intellij/testFramework/fixtures/JavaCodeInsightFixtureTestCase.java b/java/testFramework/src/com/intellij/testFramework/fixtures/JavaCodeInsightFixtureTestCase.java
index 4fc029dcd86c..d811f49e3358 100644
--- a/java/testFramework/src/com/intellij/testFramework/fixtures/JavaCodeInsightFixtureTestCase.java
+++ b/java/testFramework/src/com/intellij/testFramework/fixtures/JavaCodeInsightFixtureTestCase.java
@@ -55,6 +55,14 @@ public abstract class JavaCodeInsightFixtureTestCase extends UsefulTestCase{
     myModule = moduleFixtureBuilder.getFixture().getModule();
   }
 
+  @Override
+  protected void tearDown() throws Exception {
+    myModule = null;
+    myFixture.tearDown();
+    myFixture = null;
+    super.tearDown();
+  }
+
   /**
    * Return relative path to the test data. Path is relative to the
    * {@link com.intellij.openapi.application.PathManager#getHomePath()}
@@ -78,13 +86,6 @@ public abstract class JavaCodeInsightFixtureTestCase extends UsefulTestCase{
 
   protected void tuneFixture(final JavaModuleFixtureBuilder moduleBuilder) throws Exception {}
 
-  @Override
-  protected void tearDown() throws Exception {
-    myModule = null;
-    myFixture.tearDown();
-    myFixture = null;
-    super.tearDown();
-  }
 
   protected Project getProject() {
     return myFixture.getProject();
diff --git a/platform/core-impl/src/com/intellij/openapi/editor/impl/IntervalTreeImpl.java b/platform/core-impl/src/com/intellij/openapi/editor/impl/IntervalTreeImpl.java
index e70292090890..46628def5b91 100644
--- a/platform/core-impl/src/com/intellij/openapi/editor/impl/IntervalTreeImpl.java
+++ b/platform/core-impl/src/com/intellij/openapi/editor/impl/IntervalTreeImpl.java
@@ -764,8 +764,10 @@ public abstract class IntervalTreeImpl<T extends MutableInterval> extends RedBla
 
   // returns true if all markers are valid
   public boolean checkMax(boolean assertInvalid) {
-    if (!VERIFY) return false;
+    return VERIFY && doCheckMax(assertInvalid);
+  }
 
+  protected boolean doCheckMax(boolean assertInvalid) {
     try {
       l.readLock().lock();
 
diff --git a/platform/lang-impl/src/com/intellij/psi/PsiAnchor.java b/platform/lang-impl/src/com/intellij/psi/PsiAnchor.java
index 6529269590fd..c50727ee7fa2 100644
--- a/platform/lang-impl/src/com/intellij/psi/PsiAnchor.java
+++ b/platform/lang-impl/src/com/intellij/psi/PsiAnchor.java
@@ -327,7 +327,7 @@ public abstract class PsiAnchor {
   @Nullable
   public static PsiElement restoreFromStubIndex(PsiFileWithStubSupport fileImpl,
                                                 int index,
-                                                IStubElementType elementType) {
+                                                @NotNull IStubElementType elementType) {
     if (fileImpl == null) return null;
     StubTree tree = fileImpl.getStubTree();
 
diff --git a/platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemImpl.java b/platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemImpl.java
index 4a38c34f6124..c4ddb41a944a 100644
--- a/platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemImpl.java
@@ -139,7 +139,7 @@ public final class LocalFileSystemImpl extends LocalFileSystemBase implements Ap
   }
 
   @TestOnly
-  public void cleanupForNextTest(Set<VirtualFile> survivors) throws IOException {
+  public void cleanupForNextTest(@NotNull Set<VirtualFile> survivors) throws IOException {
     ApplicationManager.getApplication().runWriteAction(new Runnable() {
       @Override
       public void run() {
diff --git a/platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/AbstractEditorProcessingOnDocumentModificationTest.java b/platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/AbstractEditorProcessingOnDocumentModificationTest.java
index 59b39a0f53c1..c49532ca9315 100644
--- a/platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/AbstractEditorProcessingOnDocumentModificationTest.java
+++ b/platform/platform-tests/testSrc/com/intellij/openapi/editor/impl/AbstractEditorProcessingOnDocumentModificationTest.java
@@ -25,6 +25,7 @@ import com.intellij.openapi.util.Trinity;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.testFramework.LightPlatformCodeInsightTestCase;
 import com.intellij.testFramework.TestFileType;
+import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
 
 import java.io.IOException;
@@ -44,7 +45,7 @@ import java.util.regex.Pattern;
  * @since 11/18/10 7:43 PM
  */
 public abstract class AbstractEditorProcessingOnDocumentModificationTest extends LightPlatformCodeInsightTestCase {
-  protected void init(@NotNull String fileText, @NotNull TestFileType type) throws IOException {
+  protected void init(@NotNull @NonNls String fileText, @NotNull TestFileType type) throws IOException {
     configureFromFileText(getFileName(type), fileText);
   }
 
@@ -52,18 +53,21 @@ public abstract class AbstractEditorProcessingOnDocumentModificationTest extends
     return getTestName(false) + type.getExtension();
   }
 
-  protected static void addFoldRegion(final int startOffset, final int endOffset, final String placeholder) {
+  protected static FoldRegion addFoldRegion(final int startOffset, final int endOffset, final String placeholder) {
+    final FoldRegion[] result = new FoldRegion[1];
     myEditor.getFoldingModel().runBatchFoldingOperation(new Runnable() {
       @Override
       public void run() {
-        myEditor.getFoldingModel().addFoldRegion(startOffset, endOffset, placeholder);
+        result[0] = myEditor.getFoldingModel().addFoldRegion(startOffset, endOffset, placeholder);
       }
     });
+    return result[0];
   }
 
-  protected static void addCollapsedFoldRegion(final int startOffset, final int endOffset, final String placeholder) {
-    addFoldRegion(startOffset, endOffset, placeholder);
+  protected static FoldRegion addCollapsedFoldRegion(final int startOffset, final int endOffset, final String placeholder) {
+    FoldRegion region = addFoldRegion(startOffset, endOffset, placeholder);
     toggleFoldRegionState(getFoldRegion(startOffset), false);
+    return region;
   }
 
   protected static void toggleFoldRegionState(final FoldRegion foldRegion, final boolean expanded) {
@@ -200,10 +204,4 @@ public abstract class AbstractEditorProcessingOnDocumentModificationTest extends
       mapper.rawAdd(visualLine, startOffset, endOffset, startLogicalLine, startLogicalColumn, endLogicalLine, endLogicalColumn, endVisualColumn, foldRegions, tabData);
     }
   }
-
-  public static void main(String[] args) {
-    setupFolding(
-      "FoldRegion +(0:600), FoldRegion +(640:1573), FoldRegion +(8130:8233), FoldRegion +(10189:10257), FoldRegion +(13582:13686), FoldRegion +(22805:22829), FoldRegion +(24069:24147), FoldRegion +(25024:25214), FoldRegion +(28313:28362), FoldRegion -(-1:-1)(invalid), FoldRegion -(-1:-1)(invalid), FoldRegion -(-1:-1)(invalid), FoldRegion -(-1:-1)(invalid)"
-    );
-  }
 }
diff --git a/platform/testFramework/src/com/intellij/testFramework/LightPlatformCodeInsightTestCase.java b/platform/testFramework/src/com/intellij/testFramework/LightPlatformCodeInsightTestCase.java
index 4966c5aca1c7..d2265d4254c4 100644
--- a/platform/testFramework/src/com/intellij/testFramework/LightPlatformCodeInsightTestCase.java
+++ b/platform/testFramework/src/com/intellij/testFramework/LightPlatformCodeInsightTestCase.java
@@ -595,7 +595,7 @@ public abstract class LightPlatformCodeInsightTestCase extends LightPlatformTest
     new CommentByLineCommentHandler().invoke(getProject(), getEditor(), getFile());
   }
   
-  protected static void executeAction(@NotNull final String actionId) {
+  protected static void executeAction(@NonNls @NotNull final String actionId) {
     CommandProcessor.getInstance().executeCommand(getProject(), new Runnable() {
       @Override
       public void run() {
diff --git a/platform/util-rt/src/com/intellij/util/containers/ContainerUtilRt.java b/platform/util-rt/src/com/intellij/util/containers/ContainerUtilRt.java
index 45bfee429047..0b0c8ddddb1e 100644
--- a/platform/util-rt/src/com/intellij/util/containers/ContainerUtilRt.java
+++ b/platform/util-rt/src/com/intellij/util/containers/ContainerUtilRt.java
@@ -86,7 +86,7 @@ public class ContainerUtilRt {
   }
 
   @NotNull
-  public static <T> LinkedList<T> newLinkedList(T... elements) {
+  public static <T> LinkedList<T> newLinkedList(@NotNull T... elements) {
     final LinkedList<T> list = newLinkedList();
     Collections.addAll(list, elements);
     return list;
@@ -103,7 +103,7 @@ public class ContainerUtilRt {
   }
 
   @NotNull
-  public static <T> ArrayList<T> newArrayList(T... elements) {
+  public static <T> ArrayList<T> newArrayList(@NotNull T... elements) {
     ArrayList<T> list = newArrayListWithCapacity(elements.length);
     Collections.addAll(list, elements);
     return list;
@@ -132,7 +132,8 @@ public class ContainerUtilRt {
     return 5 + size + size / 5;
   }
 
-  private static <T, C extends Collection<T>> C copy(C collection, @NotNull Iterable<? extends T> elements) {
+  @NotNull
+  private static <T, C extends Collection<T>> C copy(@NotNull C collection, @NotNull Iterable<? extends T> elements) {
     for (T element : elements) {
       collection.add(element);
     }
@@ -145,7 +146,7 @@ public class ContainerUtilRt {
   }
 
   @NotNull
-  public static <T> HashSet<T> newHashSet(T... elements) {
+  public static <T> HashSet<T> newHashSet(@NotNull T... elements) {
     return new com.intellij.util.containers.HashSet<T>(Arrays.asList(elements));
   }
 
@@ -171,7 +172,7 @@ public class ContainerUtilRt {
   }
 
   @NotNull
-  public static <T> LinkedHashSet<T> newLinkedHashSet(T... elements) {
+  public static <T> LinkedHashSet<T> newLinkedHashSet(@NotNull T... elements) {
     return newLinkedHashSet(Arrays.asList(elements));
   }
 
@@ -190,7 +191,7 @@ public class ContainerUtilRt {
   }
 
   @NotNull
-  public static <T> TreeSet<T> newTreeSet(T... elements) {
+  public static <T> TreeSet<T> newTreeSet(@NotNull T... elements) {
     TreeSet<T> set = newTreeSet();
     Collections.addAll(set, elements);
     return set;
@@ -212,48 +213,62 @@ public class ContainerUtilRt {
   }
 
   @NotNull
-  public static <T> Stack<T> newStack(Collection<T> elements) {
+  public static <T> Stack<T> newStack(@NotNull Collection<T> elements) {
     return new Stack<T>(elements);
   }
 
   @NotNull
-  public static <T> Stack<T> newStack(T... initial) {
+  public static <T> Stack<T> newStack(@NotNull T... initial) {
     return new Stack<T>(Arrays.asList(initial));
   }
 
   /**
    * Optimized toArray() as opposed to the {@link java.util.Collections#emptyList()}.
    */
-  private static class EmptyList extends AbstractList<Object> implements RandomAccess {
+  private static class EmptyList<T> extends AbstractList<T> implements RandomAccess {
     private static final EmptyList INSTANCE = new EmptyList();
 
+    @Override
     public int size() {
       return 0;
     }
 
+    @Override
     public boolean contains(Object obj) {
       return false;
     }
 
-    public Object get(int index) {
+    @Override
+    public T get(int index) {
       throw new IndexOutOfBoundsException("Index: " + index);
     }
 
+    @NotNull
     @Override
     public Object[] toArray() {
       return ArrayUtilRt.EMPTY_OBJECT_ARRAY;
     }
 
+    @NotNull
     @Override
-    public <T> T[] toArray(T[] a) {
+    public <T> T[] toArray(@NotNull T[] a) {
+      if (a.length != 0) {
+        a[0] = null;
+      }
       return a;
     }
+
+    @NotNull
+    @Override
+    public Iterator<T> iterator() {
+      return EmptyIterator.getInstance();
+    }
   }
 
   @NotNull
   public static <T> List<T> emptyList() {
-    @SuppressWarnings({"unchecked"}) final List<T> list = (List<T>)EmptyList.INSTANCE;
-    return list;
+    //noinspection unchecked
+    return (List<T>)EmptyList.INSTANCE;
   }
 
   @NotNull
diff --git a/platform/util/src/com/intellij/util/containers/ContainerUtil.java b/platform/util/src/com/intellij/util/containers/ContainerUtil.java
index 03fd44e0fbea..030124122e9f 100644
--- a/platform/util/src/com/intellij/util/containers/ContainerUtil.java
+++ b/platform/util/src/com/intellij/util/containers/ContainerUtil.java
@@ -42,7 +42,7 @@ public class ContainerUtil extends ContainerUtilRt {
   private static final int INSERTION_SORT_THRESHOLD = 10;
 
   @NotNull
-  public static <T> T[] ar(T... elements) {
+  public static <T> T[] ar(@NotNull T... elements) {
     return elements;
   }
 
@@ -97,7 +97,7 @@ public class ContainerUtil extends ContainerUtilRt {
   }
 
   @NotNull
-  public static <T> LinkedList<T> newLinkedList(T... elements) {
+  public static <T> LinkedList<T> newLinkedList(@NotNull T... elements) {
     return ContainerUtilRt.newLinkedList(elements);
   }
 
@@ -112,7 +112,7 @@ public class ContainerUtil extends ContainerUtilRt {
   }
 
   @NotNull
-  public static <E> ArrayList<E> newArrayList(E... array) {
+  public static <E> ArrayList<E> newArrayList(@NotNull E... array) {
     return ContainerUtilRt.newArrayList(array);
   }
 
@@ -159,7 +159,7 @@ public class ContainerUtil extends ContainerUtilRt {
   }
 
   @NotNull
-  public static <T> HashSet<T> newHashSet(T... elements) {
+  public static <T> HashSet<T> newHashSet(@NotNull T... elements) {
     return ContainerUtilRt.newHashSet(elements);
   }
 
@@ -184,7 +184,7 @@ public class ContainerUtil extends ContainerUtilRt {
   }
 
   @NotNull
-  public static <T> LinkedHashSet<T> newLinkedHashSet(T... elements) {
+  public static <T> LinkedHashSet<T> newLinkedHashSet(@NotNull T... elements) {
     return ContainerUtilRt.newLinkedHashSet(elements);
   }
 
@@ -199,7 +199,7 @@ public class ContainerUtil extends ContainerUtilRt {
   }
 
   @NotNull
-  public static <T> THashSet<T> newTroveSet(T... elements) {
+  public static <T> THashSet<T> newTroveSet(@NotNull T... elements) {
     return newTroveSet(Arrays.asList(elements));
   }
 
@@ -236,7 +236,7 @@ public class ContainerUtil extends ContainerUtilRt {
   }
 
   @NotNull
-  public static <T> TreeSet<T> newTreeSet(T... elements) {
+  public static <T> TreeSet<T> newTreeSet(@NotNull T... elements) {
     return ContainerUtilRt.newTreeSet(elements);
   }
 
@@ -250,7 +250,8 @@ public class ContainerUtil extends ContainerUtilRt {
     return new ConcurrentHashMap<K, V>();
   }
 
-  public static <E> List<E> reverse(final List<E> elements) {
+  @NotNull
+  public static <E> List<E> reverse(@NotNull final List<E> elements) {
     return new AbstractList<E>() {
       @Override
       public E get(int index) {
@@ -264,6 +265,7 @@ public class ContainerUtil extends ContainerUtilRt {
     };
   }
 
+  @NotNull
   public static <K, V> Map<K, V> union(@NotNull Map<? extends K, ? extends V> map, @NotNull Map<? extends K, ? extends V> map2) {
     THashMap<K, V> result = new THashMap<K, V>(map.size() + map2.size());
     result.putAll(map);
@@ -271,6 +273,7 @@ public class ContainerUtil extends ContainerUtilRt {
     return result;
   }
 
+  @NotNull
   public static <T> Set<T> union(@NotNull Set<T> set, @NotNull Set<T> set2) {
     THashSet<T> result = new THashSet<T>(set.size() + set2.size());
     result.addAll(set);
@@ -278,24 +281,28 @@ public class ContainerUtil extends ContainerUtilRt {
     return result;
   }
 
-  public static <E> Set<E> immutableSet(final E ... elements) {
+  @NotNull
+  public static <E> Set<E> immutableSet(@NotNull E ... elements) {
     return Collections.unmodifiableSet(new THashSet<E>(Arrays.asList(elements)));
   }
 
-  public static <E> ImmutableList<E> immutableList(E ... array) {
+  @NotNull
+  public static <E> ImmutableList<E> immutableList(@NotNull E ... array) {
     return new ImmutableListBackedByArray<E>(array);
   }
 
-  public static <E> ImmutableList<E> immutableList(List<E> list) {
+  @NotNull
+  public static <E> ImmutableList<E> immutableList(@NotNull List<E> list) {
     return new ImmutableListBackedByList<E>(list);
   }
 
+  @NotNull
   public static <K, V> ImmutableMapBuilder<K, V> immutableMapBuilder() {
     return new ImmutableMapBuilder<K, V>();
   }
 
   public static class ImmutableMapBuilder<K, V> {
-    private THashMap<K, V> myMap = new THashMap<K, V>();
+    private final Map<K, V> myMap = new THashMap<K, V>();
 
     public ImmutableMapBuilder<K, V> put(K key, V value) {
       myMap.put(key, value);
@@ -310,7 +317,7 @@ public class ContainerUtil extends ContainerUtilRt {
   private static class ImmutableListBackedByList<E> extends ImmutableList<E> {
     private final List<E> myStore;
 
-    private ImmutableListBackedByList(List<E> list) {
+    private ImmutableListBackedByList(@NotNull List<E> list) {
       myStore = list;
     }
 
@@ -328,7 +335,7 @@ public class ContainerUtil extends ContainerUtilRt {
   private static class ImmutableListBackedByArray<E> extends ImmutableList<E> {
     private final E[] myStore;
 
-    private ImmutableListBackedByArray(E[] array) {
+    private ImmutableListBackedByArray(@NotNull E[] array) {
       myStore = array;
     }
 
@@ -343,7 +350,8 @@ public class ContainerUtil extends ContainerUtilRt {
     }
   }
 
-  public static <K, V> Map<K, V> intersection(Map<K, V> map1, Map<K, V> map2) {
+  @NotNull
+  public static <K, V> Map<K, V> intersection(@NotNull Map<K, V> map1, @NotNull Map<K, V> map2) {
     final Map<K, V> res = newHashMap();
     final Set<K> keys = newHashSet();
     keys.addAll(map1.keySet());
@@ -351,14 +359,15 @@ public class ContainerUtil extends ContainerUtilRt {
     for (K k : keys) {
       V v1 = map1.get(k);
       V v2 = map2.get(k);
-      if (v1 == v2 || (v1 != null && v1.equals(v2))) {
+      if (v1 == v2 || v1 != null && v1.equals(v2)) {
         res.put(k, v1);
       }
     }
     return res;
   }
 
-  public static <K, V> Map<K,Pair<V,V>> diff(Map<K, V> map1, Map<K, V> map2) {
+  @NotNull
+  public static <K, V> Map<K,Pair<V,V>> diff(@NotNull Map<K, V> map1, @NotNull Map<K, V> map2) {
     final Map<K, Pair<V,V>> res = newHashMap();
     final Set<K> keys = newHashSet();
     keys.addAll(map1.keySet());
@@ -366,53 +375,70 @@ public class ContainerUtil extends ContainerUtilRt {
     for (K k : keys) {
       V v1 = map1.get(k);
       V v2 = map2.get(k);
-      if (!(v1 == v2 || (v1 != null && v1.equals(v2)))) {
+      if (!(v1 == v2 || v1 != null && v1.equals(v2))) {
         res.put(k, Pair.create(v1, v2));
       }
     }
     return res;
   }
 
-  @NotNull
-  public static <T> List<T> mergeSortedLists(@NotNull List<T> list1, @NotNull List<T> list2, @NotNull Comparator<? super T> comparator, boolean mergeEqualItems){
-    List<T> result = new ArrayList<T>(list1.size() + list2.size());
-
+  public static <T> boolean processSortedListsInOrder(@NotNull List<T> list1,
+                                                      @NotNull List<T> list2,
+                                                      @NotNull Comparator<? super T> comparator,
+                                                      boolean mergeEqualItems,
+                                                      @NotNull Processor<T> processor) {
     int index1 = 0;
     int index2 = 0;
     while (index1 < list1.size() || index2 < list2.size()) {
+      T e;
       if (index1 >= list1.size()) {
-        result.add(list2.get(index2++));
+        e = list2.get(index2++);
       }
       else if (index2 >= list2.size()) {
-        result.add(list1.get(index1++));
+        e = list1.get(index1++);
       }
       else {
         T element1 = list1.get(index1);
         T element2 = list2.get(index2);
         int c = comparator.compare(element1, element2);
-        if (c < 0) {
-          result.add(element1);
+        if (c <= 0) {
+          e = element1;
           index1++;
         }
-        else if (c > 0) {
-          result.add(element2);
-          index2++;
-        }
         else {
-          result.add(element1);
-          if (!mergeEqualItems) {
-            result.add(element2);
-          }
-          index1++;
+          e = element2;
           index2++;
         }
+        if (c == 0 && !mergeEqualItems) {
+          if (!processor.process(e)) return false;
+          index2++;
+          e = element2;
+        }
       }
+      if (!processor.process(e)) return false;
     }
 
+    return true;
+  }
+
+  @NotNull
+  public static <T> List<T> mergeSortedLists(@NotNull List<T> list1,
+                                             @NotNull List<T> list2,
+                                             @NotNull Comparator<? super T> comparator,
+                                             boolean mergeEqualItems) {
+    final List<T> result = new ArrayList<T>(list1.size() + list2.size());
+    processSortedListsInOrder(list1, list2, comparator, mergeEqualItems, new Processor<T>() {
+      @Override
+      public boolean process(T t) {
+        result.add(t);
+        return true;
+      }
+    });
     return result;
   }
+
   @NotNull
-  public static <T> List<T> mergeSortedArrays(@NotNull T[] list1, @NotNull T[] list2, @NotNull Comparator<? super T> comparator, boolean mergeEqualItems, @Nullable Processor<? super T> filter){
+  public static <T> List<T> mergeSortedArrays(@NotNull T[] list1, @NotNull T[] list2, @NotNull Comparator<? super T> comparator, boolean mergeEqualItems, @Nullable Processor<? super T> filter) {
     int index1 = 0;
     int index2 = 0;
     List<T> result = new ArrayList<T>(list1.length + list2.length);
@@ -462,7 +488,8 @@ public class ContainerUtil extends ContainerUtilRt {
     return result;
   }
 
-  public static <T> List<T> subList(List<T> list, int from) {
+  @NotNull
+  public static <T> List<T> subList(@NotNull List<T> list, int from) {
     return list.subList(from, list.size());
   }
 
@@ -624,6 +651,7 @@ public class ContainerUtil extends ContainerUtilRt {
   @Nullable
   public static <T> T find(@NotNull Iterable<? extends T> iterable, final T equalTo) {
     return find(iterable, new Condition<T>() {
+      @Override
       public boolean value(final T object) {
         return equalTo == object || equalTo.equals(object);
       }
@@ -764,6 +792,7 @@ public class ContainerUtil extends ContainerUtilRt {
     }
   }
 
+  @NotNull
   public static Map<String, String> stringMap(@NotNull final String... keyValues) {
     final Map<String, String> result = newHashMap();
     for (int i = 0; i < keyValues.length - 1; i+=2) {
@@ -781,14 +810,17 @@ public class ContainerUtil extends ContainerUtilRt {
   @NotNull
   public static <T> Iterator<T> iterate(@NotNull final Enumeration<T> enumeration) {
     return new Iterator<T>() {
+      @Override
       public boolean hasNext() {
         return enumeration.hasMoreElements();
       }
 
+      @Override
       public T next() {
         return enumeration.nextElement();
       }
 
+      @Override
       public void remove() {
         throw new UnsupportedOperationException();
       }
@@ -804,15 +836,18 @@ public class ContainerUtil extends ContainerUtilRt {
   public static <T> Iterable<T> iterate(@NotNull final Collection<? extends T> collection, @NotNull final Condition<? super T> condition) {
     if (collection.isEmpty()) return emptyIterable();
     return new Iterable<T>() {
+      @Override
       public Iterator<T> iterator() {
         return new Iterator<T>() {
           Iterator<? extends T> impl = collection.iterator();
           T next = findNext();
 
+          @Override
           public boolean hasNext() {
             return next != null;
           }
 
+          @Override
           public T next() {
             T result = next;
             next = findNext();
@@ -830,6 +865,7 @@ public class ContainerUtil extends ContainerUtilRt {
             return null;
           }
 
+          @Override
           public void remove() {
             throw new UnsupportedOperationException();
           }
@@ -841,18 +877,22 @@ public class ContainerUtil extends ContainerUtilRt {
   @NotNull
   public static <T> Iterable<T> iterateBackward(@NotNull final List<? extends T> list) {
     return new Iterable<T>() {
+      @Override
       public Iterator<T> iterator() {
         return new Iterator<T>() {
           ListIterator<? extends T> it = list.listIterator(list.size());
 
+          @Override
           public boolean hasNext() {
             return it.hasPrevious();
           }
 
+          @Override
           public T next() {
             return it.previous();
           }
 
+          @Override
           public void remove() {
             it.remove();
           }
@@ -880,6 +920,7 @@ public class ContainerUtil extends ContainerUtilRt {
     }
   }
 
+  @NotNull
   public static <T, A extends T, C extends Collection<T>> C addAll(@NotNull C collection, @NotNull A... elements) {
     //noinspection ManualArrayToCollectionCopy
     for (T element : elements) {
@@ -891,6 +932,7 @@ public class ContainerUtil extends ContainerUtilRt {
   /**
    * Adds all not-null elements from the {@code elements}, ignoring nulls
    */
+  @NotNull
   public static <T, A extends T, C extends Collection<T>> C addAllNotNull(@NotNull C collection, @NotNull A... elements) {
     //noinspection ManualArrayToCollectionCopy
     for (T element : elements) {
@@ -936,6 +978,7 @@ public class ContainerUtil extends ContainerUtilRt {
     final int size = size1 + list2.size();
 
     return new AbstractList<T>() {
+      @Override
       public T get(int index) {
         if (index < size1) {
           return list1.get(index);
@@ -944,6 +987,7 @@ public class ContainerUtil extends ContainerUtilRt {
         return list2.get(index - size1);
       }
 
+      @Override
       public int size() {
         return size;
       }
@@ -953,6 +997,7 @@ public class ContainerUtil extends ContainerUtilRt {
   @NotNull
   public static <T> Iterable<T> concat(@NotNull final Iterable<? extends T>... iterables) {
     return new Iterable<T>() {
+      @Override
       public Iterator<T> iterator() {
         Iterator[] iterators = new Iterator[iterables.length];
         for (int i = 0, iterablesLength = iterables.length; i < iterablesLength; i++) {
@@ -966,6 +1011,7 @@ public class ContainerUtil extends ContainerUtilRt {
   @NotNull
   public static <T> Iterable<T> concat(@NotNull final T[]... iterables) {
     return new Iterable<T>() {
+      @Override
       public Iterator<T> iterator() {
         Iterator[] iterators = new Iterator[iterables.length];
         for (int i = 0, iterablesLength = iterables.length; i < iterablesLength; i++) {
@@ -985,6 +1031,7 @@ public class ContainerUtil extends ContainerUtilRt {
     }
     final int finalSize = size;
     return new AbstractList<T>() {
+      @Override
       public T get(final int index) {
         if (index >= 0 && index < finalSize) {
           int from = 0;
@@ -996,6 +1043,7 @@ public class ContainerUtil extends ContainerUtilRt {
         throw new IndexOutOfBoundsException("index: " + index + "size: " + size());
       }
 
+      @Override
       public int size() {
         return finalSize;
       }
@@ -1039,7 +1087,7 @@ public class ContainerUtil extends ContainerUtilRt {
   }
 
   @Nullable
-  public static <T> T getFirstItem(final Collection<T> items) {
+  public static <T> T getFirstItem(@Nullable Collection<T> items) {
     return getFirstItem(items, null);
   }
 
@@ -1065,14 +1113,17 @@ public class ContainerUtil extends ContainerUtilRt {
     return set;
   }
 
+  @NotNull
   public static <T> T[] toArray(@Nullable Collection<T> c, @NotNull ArrayFactory<T> factory) {
     return c != null ? c.toArray(factory.create(c.size())) : factory.create(0);
   }
 
+  @NotNull
   public static <T> T[] toArray(@NotNull Collection<? extends T> c1, @NotNull Collection<? extends T> c2, @NotNull ArrayFactory<T> factory) {
     return ArrayUtil.mergeCollections(c1, c2, factory);
   }
 
+  @NotNull
   public static <T> T[] mergeCollectionsToArray(@NotNull Collection<? extends T> c1, @NotNull Collection<? extends T> c2, @NotNull ArrayFactory<T> factory) {
     return ArrayUtil.mergeCollections(c1, c2, factory);
   }
@@ -1219,9 +1270,11 @@ public class ContainerUtil extends ContainerUtilRt {
   }
 
   @NotNull
-  public static <T, V> List<V> mapNotNull(@NotNull T[] array, Function<T, V> mapping) {
+  public static <T, V> List<V> mapNotNull(@NotNull T[] array, @NotNull Function<T, V> mapping) {
     return mapNotNull(Arrays.asList(array), mapping);
   }
+
+  @NotNull
   public static <T, V> V[] mapNotNull(@NotNull T[] arr, @NotNull Function<T, V> mapping, @NotNull V[] emptyArray) {
     List<V> result = new ArrayList<V>(arr.length);
     for (T t : arr) {
@@ -1234,7 +1287,7 @@ public class ContainerUtil extends ContainerUtilRt {
   }
 
   @NotNull
-  public static <T, V> List<V> mapNotNull(Iterable<? extends T> iterable, Function<T, V> mapping) {
+  public static <T, V> List<V> mapNotNull(@NotNull Iterable<? extends T> iterable, @NotNull Function<T, V> mapping) {
     List<V> result = new ArrayList<V>();
     for (T t : iterable) {
       final V o = mapping.fun(t);
@@ -1244,8 +1297,9 @@ public class ContainerUtil extends ContainerUtilRt {
     }
     return result;
   }
+
   @NotNull
-  public static <T, V> List<V> mapNotNull(Collection<? extends T> iterable, Function<T, V> mapping) {
+  public static <T, V> List<V> mapNotNull(@NotNull Collection<? extends T> iterable, @NotNull Function<T, V> mapping) {
     List<V> result = new ArrayList<V>(iterable.size());
     for (T t : iterable) {
       final V o = mapping.fun(t);
@@ -1284,7 +1338,7 @@ public class ContainerUtil extends ContainerUtilRt {
   }
 
   @NotNull
-  public static <T> Set<T> set(T ... items) {
+  public static <T> Set<T> set(@NotNull T ... items) {
     return addAll(newHashSet(items));
   }
   
@@ -1297,6 +1351,7 @@ public class ContainerUtil extends ContainerUtilRt {
   public static <T> void add(final T element, @NotNull final Collection<T> result, @NotNull final Disposable parentDisposable) {
     if (result.add(element)) {
       Disposer.register(parentDisposable, new Disposable() {
+        @Override
         public void dispose() {
           result.remove(element);
         }
@@ -1361,6 +1416,7 @@ public class ContainerUtil extends ContainerUtilRt {
     return false;
   }
 
+  @NotNull
   public static <T> List<T> unfold(@Nullable T t, @NotNull NullableFunction<T, T> next) {
     if (t == null) return Collections.emptyList();
 
@@ -1473,10 +1529,10 @@ public class ContainerUtil extends ContainerUtilRt {
    * Merge sorted points, which are sorted by x and with equal x by y.
    * Result is put to x1 y1.
    */
-  public static void mergeSortedArrays(TIntArrayList x1,
-                                       TIntArrayList y1,
-                                       TIntArrayList x2,
-                                       TIntArrayList y2) {
+  public static void mergeSortedArrays(@NotNull TIntArrayList x1,
+                                       @NotNull TIntArrayList y1,
+                                       @NotNull TIntArrayList x2,
+                                       @NotNull TIntArrayList y2) {
     TIntArrayList newX = new TIntArrayList();
     TIntArrayList newY = new TIntArrayList();
 
@@ -1484,12 +1540,12 @@ public class ContainerUtil extends ContainerUtilRt {
     int j = 0;
 
     while (i < x1.size() && j < x2.size()) {
-      if (x1.get(i) < x2.get(j) || (x1.get(i) == x2.get(j) && y1.get(i) < y2.get(j))) {
+      if (x1.get(i) < x2.get(j) || x1.get(i) == x2.get(j) && y1.get(i) < y2.get(j)) {
         newX.add(x1.get(i));
         newY.add(y1.get(i));
         i++;
       }
-      else if (x1.get(i) > x2.get(j) || (x1.get(i) == x2.get(j) && y1.get(i) > y2.get(j))) {
+      else if (x1.get(i) > x2.get(j) || x1.get(i) == x2.get(j) && y1.get(i) > y2.get(j)) {
         newX.add(x2.get(j));
         newY.add(y2.get(j));
         j++;
@@ -1523,72 +1579,91 @@ public class ContainerUtil extends ContainerUtilRt {
   @NotNull
   public static <T> Set<T> singleton(final T o, @NotNull final TObjectHashingStrategy<T> strategy) {
     return new Set<T>() {
+      @Override
       public int size() {
         return 1;
       }
 
+      @Override
       public boolean isEmpty() {
         return false;
       }
 
+      @Override
       public boolean contains(Object elem) {
         return strategy.equals(o, (T)elem);
       }
 
+      @NotNull
+      @Override
       public Iterator<T> iterator() {
         return new Iterator<T>() {
           boolean atEnd;
 
+          @Override
           public boolean hasNext() {
             return !atEnd;
           }
 
+          @Override
           public T next() {
             if (atEnd) throw new NoSuchElementException();
             atEnd = true;
             return o;
           }
 
+          @Override
           public void remove() {
             throw new IncorrectOperationException();
           }
         };
       }
 
+      @NotNull
+      @Override
       public Object[] toArray() {
         return new Object[]{o};
       }
 
+      @NotNull
+      @Override
       public <T> T[] toArray(T[] a) {
         assert a.length == 1;
         a[0] = (T)o;
         return a;
       }
 
+      @Override
       public boolean add(T t) {
         throw new IncorrectOperationException();
       }
 
+      @Override
       public boolean remove(Object o) {
         throw new IncorrectOperationException();
       }
 
+      @Override
       public boolean containsAll(Collection<?> c) {
         return false;
       }
 
+      @Override
       public boolean addAll(Collection<? extends T> c) {
         throw new IncorrectOperationException();
       }
 
+      @Override
       public boolean retainAll(Collection<?> c) {
         throw new IncorrectOperationException();
       }
 
+      @Override
       public boolean removeAll(Collection<?> c) {
         throw new IncorrectOperationException();
       }
 
+      @Override
       public void clear() {
         throw new IncorrectOperationException();
       }
@@ -1599,6 +1674,7 @@ public class ContainerUtil extends ContainerUtilRt {
   public static <E> List<E> flatten(@NotNull Collection<E>[] collections) {
     return flatten(Arrays.asList(collections));
   }
+
   @NotNull
   public static <E> List<E> flatten(@NotNull Iterable<? extends Collection<E>> collections) {
     List<E> result = new ArrayList<E>();
@@ -1609,7 +1685,8 @@ public class ContainerUtil extends ContainerUtilRt {
     return result;
   }
 
-  public static <K,V> V[] convert(K[] from, V[] to, Function<K,V> fun) {
+  @NotNull
+  public static <K,V> V[] convert(@NotNull K[] from, @NotNull V[] to, @NotNull Function<K,V> fun) {
     if (to.length < from.length) {
       to = (V[])Array.newInstance(to.getClass().getComponentType(), from.length);
     }
@@ -1619,7 +1696,7 @@ public class ContainerUtil extends ContainerUtilRt {
     return to;
   }
 
-  public static <T> boolean containsIdentity(Iterable<T> list, T element) {
+  public static <T> boolean containsIdentity(@NotNull Iterable<T> list, T element) {
     for (T t : list) {
       if (t == element) {
         return true;
@@ -1628,7 +1705,7 @@ public class ContainerUtil extends ContainerUtilRt {
     return false;
   }
 
-  public static <T> int indexOfIdentity(List<T> list, T element) {
+  public static <T> int indexOfIdentity(@NotNull List<T> list, T element) {
     for (int i = 0, listSize = list.size(); i < listSize; i++) {
       if (list.get(i) == element) {
         return i;
@@ -1638,7 +1715,7 @@ public class ContainerUtil extends ContainerUtilRt {
 
   }
 
-  public static <T> boolean equalsIdentity(List<T> list1, List<T> list2) {
+  public static <T> boolean equalsIdentity(@NotNull List<T> list1, @NotNull List<T> list2) {
     int listSize = list1.size();
     if (list2.size() != listSize) {
       return false;
@@ -1653,7 +1730,7 @@ public class ContainerUtil extends ContainerUtilRt {
 
   }
 
-  public static <T> int indexOf(List<T> list, Condition<T> condition) {
+  public static <T> int indexOf(@NotNull List<T> list, @NotNull Condition<T> condition) {
     for (int i = 0, listSize = list.size(); i < listSize; i++) {
       T t = list.get(i);
       if (condition.value(t)) {
@@ -1663,7 +1740,8 @@ public class ContainerUtil extends ContainerUtilRt {
     return -1;
   }
 
-  public static <A,B> Map<B,A> reverseMap(Map<A,B> map) {
+  @NotNull
+  public static <A,B> Map<B,A> reverseMap(@NotNull Map<A,B> map) {
     final Map<B,A> result = newHashMap();
     for (A a : map.keySet()) {
       result.put(map.get(a), a);
@@ -1671,7 +1749,7 @@ public class ContainerUtil extends ContainerUtilRt {
     return result;
   }
 
-  public static <T> boolean processRecursively(final T root, final PairProcessor<T, List<T>> processor) {
+  public static <T> boolean processRecursively(final T root, @NotNull PairProcessor<T, List<T>> processor) {
     final LinkedList<T> list = new LinkedList<T>();
     list.add(root);
     while (!list.isEmpty()) {
@@ -1699,12 +1777,12 @@ public class ContainerUtil extends ContainerUtilRt {
   }
 
   @NotNull
-  public static <T> Stack<T> newStack(Collection<T> initial) {
+  public static <T> Stack<T> newStack(@NotNull Collection<T> initial) {
     return ContainerUtilRt.newStack(initial);
   }
 
   @NotNull
-  public static <T> Stack<T> newStack(T... initial) {
+  public static <T> Stack<T> newStack(@NotNull T... initial) {
     return ContainerUtilRt.newStack(initial);
   }
 
@@ -1718,6 +1796,10 @@ public class ContainerUtil extends ContainerUtilRt {
     return ContainerUtilRt.createEmptyCOWList();
   }
 
+  public static <T> List<T> createLockFreeCopyOnWriteList(@NotNull Collection<? extends T> c) {
+    return new CopyOnWriteArrayList<T>(c);
+  }
+
   public static <T> void addIfNotNull(@Nullable T element, @NotNull Collection<T> result) {
     ContainerUtilRt.addIfNotNull(element, result);
   }
diff --git a/platform/util/src/com/intellij/util/containers/UnsafeWeakList.java b/platform/util/src/com/intellij/util/containers/UnsafeWeakList.java
index 57d8ed8fc2a9..cca415694f6e 100644
--- a/platform/util/src/com/intellij/util/containers/UnsafeWeakList.java
+++ b/platform/util/src/com/intellij/util/containers/UnsafeWeakList.java
@@ -41,10 +41,12 @@ public class UnsafeWeakList<T> extends AbstractList<T> {
     myArray = array;
   }
 
+  @Override
   public T get(int index) {
     return myArray.get(index);
   }
 
+  @Override
   public boolean add(T element) {
     tryReduceCapacity(-1);
     myArray.add(element);
@@ -63,24 +65,33 @@ public class UnsafeWeakList<T> extends AbstractList<T> {
     return true;
   }
 
+  @Override
   public void add(int index, T element) {
     tryReduceCapacity(-1);
     myArray.add(index, element);
   }
 
+  @Override
   public T remove(int index) {
     tryReduceCapacity(-1);
     return myArray.remove(index);
   }
 
+  @NotNull
+  @Override
   public Iterator<T> iterator() {
     return new MyIterator();
   }
 
+  @Override
   public int size() {
     return myArray.size();
   }
 
+  public void clear(int index) {
+    myArray.removeReference(index);
+  }
+
   public List<T> toStrongList() {
     List<T> result = new ArrayList<T>(myArray.size());
     myArray.toStrongCollection(result);
@@ -134,10 +145,12 @@ public class UnsafeWeakList<T> extends AbstractList<T> {
       }
     }
 
+    @Override
     public boolean hasNext() {
       return myNextElement != null;
     }
 
+    @Override
     public T next() {
       if (modCount != myModCount) throw new ConcurrentModificationException();
       if (myNextElement == null) throw new NoSuchElementException();
@@ -147,6 +160,7 @@ public class UnsafeWeakList<T> extends AbstractList<T> {
       return element;
     }
 
+    @Override
     public void remove() {
       if (myCurrentIndex == -1) throw new IllegalStateException();
       myArray.remove(myCurrentIndex);