diff --git a/platform/core-api/src/com/intellij/openapi/options/SchemesManagerFactory.java b/platform/core-api/src/com/intellij/openapi/options/SchemesManagerFactory.java
index a0c0ee7dad62..abd37269985f 100644
--- a/platform/core-api/src/com/intellij/openapi/options/SchemesManagerFactory.java
+++ b/platform/core-api/src/com/intellij/openapi/options/SchemesManagerFactory.java
@@ -25,9 +25,8 @@ public abstract class SchemesManagerFactory {
   public static final ExtensionPointName<ServiceBean> SCHEME_OWNER = ExtensionPointName.create("com.intellij.schemeOwner");
 
   public abstract <T extends Scheme, E extends ExternalizableScheme> SchemesManager<T, E> createSchemesManager(@NotNull String fileSpec,
-                                                                                                               @NotNull SchemeProcessor<E> processor,
-                                                                                                               @NotNull RoamingType roamingType);
-
+                                                                                                               @NotNull SchemeProcessor<E> processor, @NotNull RoamingType roamingType);
+  @NotNull
   public static SchemesManagerFactory getInstance() {
     return ServiceManager.getService(SchemesManagerFactory.class);
   }
diff --git a/platform/core-api/src/com/intellij/openapi/progress/ProgressManager.java b/platform/core-api/src/com/intellij/openapi/progress/ProgressManager.java
index 3f0601ba951b..377bcc520e27 100644
--- a/platform/core-api/src/com/intellij/openapi/progress/ProgressManager.java
+++ b/platform/core-api/src/com/intellij/openapi/progress/ProgressManager.java
@@ -34,6 +34,7 @@ public abstract class ProgressManager extends ProgressIndicatorProvider {
     private static final ProgressManager ourInstance = ServiceManager.getService(ProgressManager.class);
   }
 
+  @NotNull
   public static ProgressManager getInstance() {
     return ProgressManagerHolder.ourInstance;
   }
diff --git a/platform/editor-ui-api/src/com/intellij/openapi/actionSystem/AnAction.java b/platform/editor-ui-api/src/com/intellij/openapi/actionSystem/AnAction.java
index 42da54a61d72..33be4de4b37d 100644
--- a/platform/editor-ui-api/src/com/intellij/openapi/actionSystem/AnAction.java
+++ b/platform/editor-ui-api/src/com/intellij/openapi/actionSystem/AnAction.java
@@ -229,7 +229,7 @@ public abstract class AnAction implements PossiblyDumbAware {
    *
    * @param e Carries information on the invocation place and data available
    */
-  public void update(AnActionEvent e) {
+  public void update(@NotNull AnActionEvent e) {
   }
 
   /**
@@ -268,7 +268,7 @@ public abstract class AnAction implements PossiblyDumbAware {
    *
    * @param e Carries information on the invocation place
    */
-  public abstract void actionPerformed(AnActionEvent e);
+  public abstract void actionPerformed(@NotNull AnActionEvent e);
 
   protected void setShortcutSet(ShortcutSet shortcutSet) {
     myShortcutSet = shortcutSet;
diff --git a/platform/platform-api/src/com/intellij/notification/NotificationGroup.java b/platform/platform-api/src/com/intellij/notification/NotificationGroup.java
index df68daff1584..a1b838676f41 100644
--- a/platform/platform-api/src/com/intellij/notification/NotificationGroup.java
+++ b/platform/platform-api/src/com/intellij/notification/NotificationGroup.java
@@ -54,18 +54,22 @@ public final class NotificationGroup {
     ourRegisteredGroups.put(displayId, this);
   }
 
+  @NotNull
   public static NotificationGroup balloonGroup(@NotNull String displayId) {
     return new NotificationGroup(displayId, NotificationDisplayType.BALLOON, true);
   }
 
+  @NotNull
   public static NotificationGroup logOnlyGroup(@NotNull String displayId) {
     return new NotificationGroup(displayId, NotificationDisplayType.NONE, true);
   }
 
+  @NotNull
   public static NotificationGroup toolWindowGroup(@NotNull String displayId, @NotNull String toolWindowId, final boolean logByDefault) {
     return new NotificationGroup(displayId, NotificationDisplayType.TOOL_WINDOW, logByDefault, toolWindowId);
   }
 
+  @NotNull
   public static NotificationGroup toolWindowGroup(@NotNull String displayId, @NotNull String toolWindowId) {
     return toolWindowGroup(displayId, toolWindowId, true);
   }
@@ -78,10 +82,12 @@ public final class NotificationGroup {
     return createNotification(content, type.toNotificationType());
   }
 
+  @NotNull
   public Notification createNotification(@NotNull final String content, @NotNull final NotificationType type) {
     return createNotification("", content, type, null);
   }
 
+  @NotNull
   public Notification createNotification(@NotNull final String title,
                                          @NotNull final String content,
                                          @NotNull final NotificationType type,
diff --git a/platform/platform-impl/src/com/intellij/ide/ApplicationLoadListener.java b/platform/platform-impl/src/com/intellij/ide/ApplicationLoadListener.java
index f1d11ff938d9..b1432f87e10d 100644
--- a/platform/platform-impl/src/com/intellij/ide/ApplicationLoadListener.java
+++ b/platform/platform-impl/src/com/intellij/ide/ApplicationLoadListener.java
@@ -17,9 +17,10 @@ package com.intellij.ide;
 
 import com.intellij.openapi.application.Application;
 import com.intellij.openapi.extensions.ExtensionPointName;
+import org.jetbrains.annotations.NotNull;
 
 public interface ApplicationLoadListener {
   ExtensionPointName<ApplicationLoadListener> EP_NAME = ExtensionPointName.create("com.intellij.ApplicationLoadListener");
 
-  void beforeApplicationLoaded(Application application);
+  void beforeApplicationLoaded(@NotNull Application application);
 }
diff --git a/platform/platform-impl/src/com/intellij/openapi/components/impl/stores/StateStorageManager.java b/platform/platform-impl/src/com/intellij/openapi/components/impl/stores/StateStorageManager.java
index 68d882d2b204..92560821612b 100644
--- a/platform/platform-impl/src/com/intellij/openapi/components/impl/stores/StateStorageManager.java
+++ b/platform/platform-impl/src/com/intellij/openapi/components/impl/stores/StateStorageManager.java
@@ -42,6 +42,7 @@ public interface StateStorageManager {
   @Nullable
   StateStorage getFileStateStorage(@NotNull String fileSpec);
 
+  @NotNull
   Collection<String> getStorageFileNames();
 
   void clearStateStorage(@NotNull String file);
diff --git a/platform/platform-impl/src/com/intellij/openapi/components/impl/stores/StreamProvider.java b/platform/platform-impl/src/com/intellij/openapi/components/impl/stores/StreamProvider.java
index 0bacfc535af0..cf49b927ad0e 100644
--- a/platform/platform-impl/src/com/intellij/openapi/components/impl/stores/StreamProvider.java
+++ b/platform/platform-impl/src/com/intellij/openapi/components/impl/stores/StreamProvider.java
@@ -12,7 +12,9 @@ import java.util.Collections;
 public abstract class StreamProvider {
   public static final StreamProvider[] EMPTY_ARRAY = new StreamProvider[0];
 
-  public abstract boolean isEnabled();
+  public boolean isEnabled() {
+    return true;
+  }
 
   /**
    * If true, special version file per storage file will keep version of component.
diff --git a/platform/platform-tests/testSrc/com/intellij/openapi/components/impl/ApplicationStoreTest.java b/platform/platform-tests/testSrc/com/intellij/openapi/components/impl/ApplicationStoreTest.java
index c2f768be503d..2d5bcb4537ff 100644
--- a/platform/platform-tests/testSrc/com/intellij/openapi/components/impl/ApplicationStoreTest.java
+++ b/platform/platform-tests/testSrc/com/intellij/openapi/components/impl/ApplicationStoreTest.java
@@ -96,11 +96,6 @@ public class ApplicationStoreTest extends LightPlatformLangTestCase {
   private static class MyStreamProvider extends StreamProvider {
     public final Map<RoamingType, Map<String, String>> data = new THashMap<RoamingType, Map<String, String>>();
 
-    @Override
-    public boolean isEnabled() {
-      return true;
-    }
-
     @Override
     public void saveContent(@NotNull String fileSpec,
                             @NotNull byte[] content,