diff --git a/platform/lang-api/src/com/intellij/refactoring/util/CommonRefactoringUtil.java b/platform/lang-api/src/com/intellij/refactoring/util/CommonRefactoringUtil.java
index 7027e44580db..1f798f92bfe5 100644
--- a/platform/lang-api/src/com/intellij/refactoring/util/CommonRefactoringUtil.java
+++ b/platform/lang-api/src/com/intellij/refactoring/util/CommonRefactoringUtil.java
@@ -41,7 +41,6 @@ import org.jetbrains.annotations.Nullable;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.Comparator;
 
 /**
  * @author ven
@@ -75,11 +74,11 @@ public class CommonRefactoringUtil {
     }
   }
 
-  public static void showErrorHint(final Project project,
-                                   @Nullable final Editor editor,
-                                   @Nls final String message,
-                                   @Nls final String title,
-                                   @Nullable final String helpId) {
+  public static void showErrorHint(@NotNull Project project,
+                                   @Nullable Editor editor,
+                                   @NotNull @Nls String message,
+                                   @NotNull @Nls String title,
+                                   @Nullable String helpId) {
     if (ApplicationManager.getApplication().isUnitTestMode()) throw new RefactoringErrorHintException(message);
 
     ApplicationManager.getApplication().invokeLater(() -> {
@@ -92,7 +91,7 @@ public class CommonRefactoringUtil {
     });
   }
 
-  public static String htmlEmphasize(String text) {
+  public static String htmlEmphasize(@NotNull String text) {
     return StringUtil.htmlEmphasize(text);
   }
 
@@ -113,7 +112,7 @@ public class CommonRefactoringUtil {
     return checkReadOnlyStatus(project, Collections.<PsiElement>emptySet(), elements, RefactoringBundle.message("refactoring.cannot.be.performed"), notifyOnFail);
   }
 
-  public static boolean checkReadOnlyStatus(@NotNull PsiElement element, @NotNull Project project, String messagePrefix) {
+  public static boolean checkReadOnlyStatus(@NotNull PsiElement element, @NotNull Project project, @NotNull String messagePrefix) {
     return element.isWritable() || checkReadOnlyStatus(project, Collections.<PsiElement>emptySet(), Collections.singleton(element), messagePrefix, true);
   }
 
@@ -246,11 +245,11 @@ public class CommonRefactoringUtil {
     });
   }
 
-  public static String capitalize(String text) {
+  public static String capitalize(@NotNull String text) {
     return StringUtil.capitalize(text);
   }
 
-  public static boolean isAncestor(final PsiElement resolved, final Collection<? extends PsiElement> scopes) {
+  public static boolean isAncestor(@NotNull PsiElement resolved, @NotNull Collection<? extends PsiElement> scopes) {
     for (final PsiElement scope : scopes) {
       if (PsiTreeUtil.isAncestor(scope, resolved, false)) return true;
     }
diff --git a/platform/lang-impl/src/com/intellij/refactoring/introduce/inplace/AbstractInplaceIntroducer.java b/platform/lang-impl/src/com/intellij/refactoring/introduce/inplace/AbstractInplaceIntroducer.java
index 7fa87d7e4e2e..ca185be22cb5 100644
--- a/platform/lang-impl/src/com/intellij/refactoring/introduce/inplace/AbstractInplaceIntroducer.java
+++ b/platform/lang-impl/src/com/intellij/refactoring/introduce/inplace/AbstractInplaceIntroducer.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2015 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -175,7 +175,7 @@ public abstract class AbstractInplaceIntroducer<V extends PsiNameIdentifierOwner
    * @return the declaration
    */
   @Nullable
-  protected abstract V createFieldToStartTemplateOn(boolean replaceAll, String[] names);
+  protected abstract V createFieldToStartTemplateOn(boolean replaceAll, @NotNull String[] names);
 
   /**
    * Returns the suggested names for the introduced element.
@@ -184,6 +184,7 @@ public abstract class AbstractInplaceIntroducer<V extends PsiNameIdentifierOwner
    * @param variable   introduced element declaration, if already created.
    * @return the suggested names
    */
+  @NotNull
   protected abstract String[] suggestNames(boolean replaceAll, @Nullable V variable);
 
   protected abstract void performIntroduce();
@@ -192,13 +193,15 @@ public abstract class AbstractInplaceIntroducer<V extends PsiNameIdentifierOwner
   public abstract boolean isReplaceAllOccurrences();
   public abstract void setReplaceAllOccurrences(boolean allOccurrences);
   @Override
+  @Nullable
   protected abstract JComponent getComponent();
 
   protected abstract void saveSettings(@NotNull V variable);
   @Override
+  @Nullable
   protected abstract V getVariable();
 
-  public abstract E restoreExpression(PsiFile containingFile, V variable, RangeMarker marker, String exprText);
+  public abstract E restoreExpression(@NotNull PsiFile containingFile, @NotNull V variable, @NotNull RangeMarker marker, @Nullable String exprText);
 
   /**
    * Begins the in-place refactoring operation.
@@ -595,7 +598,7 @@ public abstract class AbstractInplaceIntroducer<V extends PsiNameIdentifierOwner
   protected String getRefactoringId() {
     return null;
   }
-  
+
   @Override
   protected boolean startsOnTheSameElement(RefactoringActionHandler handler, PsiElement element) {
     return super.startsOnTheSameElement(handler, element) || getLocalVariable() == element;