diff --git a/platform/lang-impl/src/com/intellij/find/replaceInProject/ReplaceInProjectManager.java b/platform/lang-impl/src/com/intellij/find/replaceInProject/ReplaceInProjectManager.java
index c0fe923f9e4c..e0ef589cd2ef 100644
--- a/platform/lang-impl/src/com/intellij/find/replaceInProject/ReplaceInProjectManager.java
+++ b/platform/lang-impl/src/com/intellij/find/replaceInProject/ReplaceInProjectManager.java
@@ -58,7 +58,6 @@ import com.intellij.usages.rules.UsageInFile;
 import com.intellij.util.AdapterProcessor;
 import com.intellij.util.Processor;
 import org.jetbrains.annotations.NotNull;
-import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
 import java.util.*;
@@ -491,8 +490,8 @@ public class ReplaceInProjectManager {
     return true;
   }
 
-  private void replaceUsagesUnderCommand(@NotNull final ReplaceContext replaceContext, @Nullable final Set<Usage> usagesSet) {
-    if (usagesSet == null) {
+  private void replaceUsagesUnderCommand(@NotNull final ReplaceContext replaceContext, @NotNull final Set<Usage> usagesSet) {
+    if (usagesSet.isEmpty()) {
       return;
     }
 
diff --git a/platform/structuralsearch/source/com/intellij/structuralsearch/plugin/replace/ui/ReplaceUsageViewContext.java b/platform/structuralsearch/source/com/intellij/structuralsearch/plugin/replace/ui/ReplaceUsageViewContext.java
index 2c43042dc847..f71d1b7fc6ef 100644
--- a/platform/structuralsearch/source/com/intellij/structuralsearch/plugin/replace/ui/ReplaceUsageViewContext.java
+++ b/platform/structuralsearch/source/com/intellij/structuralsearch/plugin/replace/ui/ReplaceUsageViewContext.java
@@ -31,6 +31,7 @@ import com.intellij.usages.Usage;
 import com.intellij.usages.UsageInfo2UsageAdapter;
 import com.intellij.usages.UsageView;
 import com.intellij.util.ObjectUtils;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.*;
 import java.util.stream.Collectors;
@@ -65,7 +66,7 @@ class ReplaceUsageViewContext extends UsageViewContext {
 
     final Runnable previewReplacement = () -> {
       final Set<Usage> selection = myUsageView.getSelectedUsages();
-      if (selection == null || selection.isEmpty()) {
+      if (selection.isEmpty()) {
         return;
       }
       for (Usage usage : selection) {
@@ -85,10 +86,7 @@ class ReplaceUsageViewContext extends UsageViewContext {
     myUsageView.addButtonToLowerPane(previewReplacement, SSRBundle.message("preview.replacement.button"));
   }
 
-  private void replace(Collection<Usage> usages) {
-    if (usages == null) {
-      return;
-    }
+  private void replace(@NotNull Collection<Usage> usages) {
     final Set<Usage> excluded = myUsageView.getExcludedUsages();
     usages = usages.stream().filter(u -> !excluded.contains(u)).filter(u -> isValid((UsageInfo2UsageAdapter)u)).collect(Collectors.toList());
 
diff --git a/platform/usageView/src/com/intellij/usages/UsageView.java b/platform/usageView/src/com/intellij/usages/UsageView.java
index 82fa8851feb7..2e93e9354f3d 100644
--- a/platform/usageView/src/com/intellij/usages/UsageView.java
+++ b/platform/usageView/src/com/intellij/usages/UsageView.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2017 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.
@@ -81,8 +81,7 @@ public interface UsageView extends Disposable {
   @NotNull
   Set<Usage> getExcludedUsages();
 
-  @Nullable
-  Set<Usage> getSelectedUsages();
+  @NotNull Set<Usage> getSelectedUsages();
   @NotNull Set<Usage> getUsages();
   @NotNull List<Usage> getSortedUsages();
 
diff --git a/platform/usageView/src/com/intellij/usages/impl/UsageViewImpl.java b/platform/usageView/src/com/intellij/usages/impl/UsageViewImpl.java
index 11cd89d8eaa7..e7bf59a5ece3 100644
--- a/platform/usageView/src/com/intellij/usages/impl/UsageViewImpl.java
+++ b/platform/usageView/src/com/intellij/usages/impl/UsageViewImpl.java
@@ -1470,12 +1470,12 @@ public class UsageViewImpl implements UsageView {
   }
 
   @Override
-  @Nullable
+  @NotNull
   public Set<Usage> getSelectedUsages() {
     ApplicationManager.getApplication().assertIsDispatchThread();
     TreePath[] selectionPaths = myTree.getSelectionPaths();
     if (selectionPaths == null) {
-      return null;
+      return Collections.emptySet();
     }
 
     Set<Usage> usages = new THashSet<>();
@@ -1679,7 +1679,7 @@ public class UsageViewImpl implements UsageView {
 
       else if (key == USAGES_KEY) {
         final Set<Usage> selectedUsages = getSelectedUsages();
-        sink.put(USAGES_KEY, selectedUsages != null ? selectedUsages.toArray(new Usage[selectedUsages.size()]) : null);
+        sink.put(USAGES_KEY, selectedUsages.toArray(new Usage[selectedUsages.size()]));
       }
 
       else if (key == USAGE_TARGETS_KEY) {