diff --git a/platform/core-api/src/com/intellij/openapi/vfs/VirtualFile.java b/platform/core-api/src/com/intellij/openapi/vfs/VirtualFile.java
index 5ac232d80274..0725d7a1ea0e 100644
--- a/platform/core-api/src/com/intellij/openapi/vfs/VirtualFile.java
+++ b/platform/core-api/src/com/intellij/openapi/vfs/VirtualFile.java
@@ -393,7 +393,8 @@ public abstract class VirtualFile extends UserDataHolderBase implements Modifica
    * @return <code>VirtualFile</code> representing the created directory
    * @throws java.io.IOException if directory failed to be created
    */
-  public VirtualFile createChildDirectory(Object requestor, @NonNls String name) throws IOException {
+  @NotNull
+  public VirtualFile createChildDirectory(Object requestor, @NotNull @NonNls String name) throws IOException {
     if (!isDirectory()) {
       throw new IOException(VfsBundle.message("directory.create.wrong.parent.error"));
     }
@@ -423,6 +424,7 @@ public abstract class VirtualFile extends UserDataHolderBase implements Modifica
    * @return <code>VirtualFile</code> representing the created file
    * @throws IOException if file failed to be created
    */
+  @NotNull
   public VirtualFile createChildData(Object requestor, @NotNull @NonNls String name) throws IOException {
     if (!isDirectory()) {
       throw new IOException(VfsBundle.message("file.create.wrong.parent.error"));
diff --git a/platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/impl/VirtualFileSystemEntry.java b/platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/impl/VirtualFileSystemEntry.java
index 48bfc01c0fa2..faf3819dfe69 100644
--- a/platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/impl/VirtualFileSystemEntry.java
+++ b/platform/platform-impl/src/com/intellij/openapi/vfs/newvfs/impl/VirtualFileSystemEntry.java
@@ -322,13 +322,13 @@ public abstract class VirtualFileSystemEntry extends NewVirtualFile {
 
   @Override
   @NotNull
-  public VirtualFile createChildDirectory(final Object requestor, final String name) throws IOException {
+  public VirtualFile createChildDirectory(final Object requestor, @NotNull final String name) throws IOException {
     validateName(name);
     return ourPersistence.createChildDirectory(requestor, this, name);
   }
 
-  private static void validateName(String name) throws IOException {
-    if (name == null || name.isEmpty()) throw new IOException("File name cannot be empty");
+  private static void validateName(@NotNull String name) throws IOException {
+    if (name.isEmpty()) throw new IOException("File name cannot be empty");
     if (name.indexOf('/') >= 0 || name.indexOf(File.separatorChar) >= 0) {
       throw new IOException("File name cannot contain file path separators: '" + name + "'");
     }
diff --git a/platform/testFramework/src/com/intellij/mock/Mock.java b/platform/testFramework/src/com/intellij/mock/Mock.java
index f0ca6a19e745..575bc0991c3e 100644
--- a/platform/testFramework/src/com/intellij/mock/Mock.java
+++ b/platform/testFramework/src/com/intellij/mock/Mock.java
@@ -494,14 +494,16 @@ public class Mock {
       return new VirtualFile[0];
     }
 
+    @NotNull
     @Override
-    public VirtualFile createChildDirectory(Object requestor, String name) throws IOException {
-      return null;
+    public VirtualFile createChildDirectory(Object requestor, @NotNull String name) throws IOException {
+      throw new IOException(name);
     }
 
+    @NotNull
     @Override
     public VirtualFile createChildData(Object requestor, @NotNull String name) throws IOException {
-      return null;
+      throw new IOException(name);
     }
 
     @Override
diff --git a/platform/testFramework/src/com/intellij/mock/MockVirtualFile.java b/platform/testFramework/src/com/intellij/mock/MockVirtualFile.java
index 9f31bbb9b10f..cd06c19af81d 100644
--- a/platform/testFramework/src/com/intellij/mock/MockVirtualFile.java
+++ b/platform/testFramework/src/com/intellij/mock/MockVirtualFile.java
@@ -72,6 +72,7 @@ public class MockVirtualFile extends VirtualFile {
     myParent = parent;
   }
 
+  @NotNull
   @Override
   public VirtualFile createChildData(final Object requestor, @NotNull @NonNls final String name) {
     final MockVirtualFile file = new MockVirtualFile(name);
diff --git a/platform/testFramework/src/com/intellij/testFramework/fixtures/impl/TempDirTestFixtureImpl.java b/platform/testFramework/src/com/intellij/testFramework/fixtures/impl/TempDirTestFixtureImpl.java
index 7493cb17bde0..dfdaf2e0acf1 100644
--- a/platform/testFramework/src/com/intellij/testFramework/fixtures/impl/TempDirTestFixtureImpl.java
+++ b/platform/testFramework/src/com/intellij/testFramework/fixtures/impl/TempDirTestFixtureImpl.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2009 JetBrains s.r.o.
+ * Copyright 2000-2014 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.
@@ -166,11 +166,13 @@ public class TempDirTestFixtureImpl extends BaseFixture implements TempDirTestFi
     return null;
   }
 
+  @NotNull
   protected File createTempDirectory() {
     try {
       if (myTempDir == null) {
-        File th = getTempHome();
-        myTempDir = th != null ? FileUtil.createTempDirectory(th, "unitTest", null,false) : FileUtil.createTempDirectory("unitTest", null,false);
+        File tempHome = getTempHome();
+        myTempDir = tempHome == null ? FileUtil.createTempDirectory("unitTest", null, false) :
+                    FileUtil.createTempDirectory(tempHome, "unitTest", null, false);
         myFilesToDelete.add(myTempDir);
       }
       return myTempDir;
diff --git a/plugins/properties/src/com/intellij/lang/properties/editor/ResourceBundleAsVirtualFile.java b/plugins/properties/src/com/intellij/lang/properties/editor/ResourceBundleAsVirtualFile.java
index f61c3b87e80b..2f799368084c 100644
--- a/plugins/properties/src/com/intellij/lang/properties/editor/ResourceBundleAsVirtualFile.java
+++ b/plugins/properties/src/com/intellij/lang/properties/editor/ResourceBundleAsVirtualFile.java
@@ -104,11 +104,13 @@ public class ResourceBundleAsVirtualFile extends VirtualFile {
     return EMPTY_ARRAY;
   }
 
+  @NotNull
   @Override
-  public VirtualFile createChildDirectory(Object requestor, String name) throws IOException {
+  public VirtualFile createChildDirectory(Object requestor, @NotNull String name) throws IOException {
     throw new UnsupportedOperationException();
   }
 
+  @NotNull
   @Override
   public VirtualFile createChildData(Object requestor, @NotNull String name) throws IOException {
     throw new UnsupportedOperationException();