diff --git a/platform/core-api/src/com/intellij/lang/LanguageExtension.java b/platform/core-api/src/com/intellij/lang/LanguageExtension.java
index 495a8301cfff..d4a385f1ab25 100644
--- a/platform/core-api/src/com/intellij/lang/LanguageExtension.java
+++ b/platform/core-api/src/com/intellij/lang/LanguageExtension.java
@@ -29,7 +29,7 @@ import java.util.List;
 
 public class LanguageExtension<T> extends KeyedExtensionCollector<T, Language> {
   private final T myDefaultImplementation;
-  private final /* non static!!! */ Key<T> IN_LANGUAGE_CACHE = new Key<T>("EXTENSIONS_IN_LANGUAGE");
+  private final /* non static!!! */ Key<T> IN_LANGUAGE_CACHE;
 
   public LanguageExtension(@NonNls final String epName) {
     this(epName, null);
@@ -38,6 +38,7 @@ public class LanguageExtension<T> extends KeyedExtensionCollector<T, Language> {
   public LanguageExtension(@NonNls final String epName, @Nullable final T defaultImplementation) {
     super(epName);
     myDefaultImplementation = defaultImplementation;
+    IN_LANGUAGE_CACHE = Key.create("EXTENSIONS_IN_LANGUAGE_"+epName);
   }
 
   @Override
@@ -59,8 +60,8 @@ public class LanguageExtension<T> extends KeyedExtensionCollector<T, Language> {
     else {
       result = extensions.get(0);
     }
-    if (result == null) return result;
-    l.putUserDataIfAbsent(IN_LANGUAGE_CACHE, result);
+    if (result == null) return null;
+    result = l.putUserDataIfAbsent(IN_LANGUAGE_CACHE, result);
     return result;
   }
 
diff --git a/platform/util/src/com/intellij/openapi/util/Disposer.java b/platform/util/src/com/intellij/openapi/util/Disposer.java
index fe05052fc5fe..65ab06fd114c 100644
--- a/platform/util/src/com/intellij/openapi/util/Disposer.java
+++ b/platform/util/src/com/intellij/openapi/util/Disposer.java
@@ -42,10 +42,12 @@ public class Disposer {
   }
 
   private static final ObjectTreeAction<Disposable> ourDisposeAction = new ObjectTreeAction<Disposable>() {
+    @Override
     public void execute(final Disposable each) {
       each.dispose();
     }
 
+    @Override
     public void beforeTreeExecution(final Disposable parent) {
       if (parent instanceof Disposable.Parent) {
         ((Disposable.Parent)parent).beforeTreeDispose();
@@ -61,6 +63,7 @@ public class Disposer {
   @NotNull
   public static Disposable newDisposable() {
     return new Disposable() {
+      @Override
       public void dispose() {
       }
     };
@@ -81,6 +84,7 @@ public class Disposer {
       assert get(key) == null;
       ourKeyDisposables.put(key, child);
       register(child, new Disposable() {
+        @Override
         public void dispose() {
           ourKeyDisposables.remove(key);
         }
diff --git a/platform/util/src/com/intellij/openapi/util/NotNullLazyKey.java b/platform/util/src/com/intellij/openapi/util/NotNullLazyKey.java
index cf4ac7892e91..d561e5ee4971 100644
--- a/platform/util/src/com/intellij/openapi/util/NotNullLazyKey.java
+++ b/platform/util/src/com/intellij/openapi/util/NotNullLazyKey.java
@@ -25,7 +25,7 @@ import com.intellij.util.NotNullFunction;
 public class NotNullLazyKey<T,H extends UserDataHolder> extends Key<T>{
   private final NotNullFunction<H,T> myFunction;
 
-  private NotNullLazyKey(@NonNls String name, final NotNullFunction<H, T> function) {
+  private NotNullLazyKey(@NotNull @NonNls String name, @NotNull NotNullFunction<H, T> function) {
     super(name);
     myFunction = function;
   }