diff --git a/platform/platform-api/src/com/intellij/openapi/vfs/LocalFileOperationsHandler.java b/platform/platform-api/src/com/intellij/openapi/vfs/LocalFileOperationsHandler.java
index 6137dd1321c7..9de3c4b79abc 100644
--- a/platform/platform-api/src/com/intellij/openapi/vfs/LocalFileOperationsHandler.java
+++ b/platform/platform-api/src/com/intellij/openapi/vfs/LocalFileOperationsHandler.java
@@ -16,6 +16,7 @@
 package com.intellij.openapi.vfs;
 
 import com.intellij.util.ThrowableConsumer;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
@@ -35,7 +36,7 @@ public interface LocalFileOperationsHandler {
    * @return true if the handler has performed the deletion, false if the deletion needs to be performed through
    * standard core logic.
    */
-  boolean delete(VirtualFile file) throws IOException;
+  boolean delete(@NotNull VirtualFile file) throws IOException;
 
   /**
    * Intercepts the movement of a file.
@@ -44,7 +45,7 @@ public interface LocalFileOperationsHandler {
    * @return true if the handler has performed the move, false if the move needs to be performed through
    * standard core logic.
    */
-  boolean move(VirtualFile file, VirtualFile toDir) throws IOException;
+  boolean move(@NotNull VirtualFile file, @NotNull VirtualFile toDir) throws IOException;
 
   /**
    * Intercepts the copying of a file.
@@ -55,7 +56,7 @@ public interface LocalFileOperationsHandler {
    * standard core logic.
    */
   @Nullable
-  File copy(VirtualFile file, VirtualFile toDir, final String copyName) throws IOException;
+  File copy(@NotNull VirtualFile file, @NotNull VirtualFile toDir, @NotNull String copyName) throws IOException;
 
   /**
    * Intercepts the renaming of a file.
@@ -64,7 +65,7 @@ public interface LocalFileOperationsHandler {
    * @return true if the handler has performed the rename, false if the rename needs to be performed through
    * standard core logic.
    */
-  boolean rename(VirtualFile file, String newName) throws IOException;
+  boolean rename(@NotNull VirtualFile file, @NotNull String newName) throws IOException;
 
   /**
    * Intercepts the creation of a file.
@@ -73,7 +74,7 @@ public interface LocalFileOperationsHandler {
    * @return true if the handler has performed the file creation, false if the creation needs to be performed through
    * standard core logic.
    */
-  boolean createFile(VirtualFile dir, String name) throws IOException;
+  boolean createFile(@NotNull VirtualFile dir, @NotNull String name) throws IOException;
 
   /**
    * Intercepts the creation of a directory.
@@ -82,7 +83,7 @@ public interface LocalFileOperationsHandler {
    * @return true if the handler has performed the directory creation, false if the creation needs to be performed through
    * standard core logic.
    */
-  boolean createDirectory(VirtualFile dir, String name) throws IOException;
+  boolean createDirectory(@NotNull VirtualFile dir, @NotNull String name) throws IOException;
 
-  void afterDone(final ThrowableConsumer<LocalFileOperationsHandler, IOException> invoker);
+  void afterDone(@NotNull ThrowableConsumer<LocalFileOperationsHandler, IOException> invoker);
 }
diff --git a/platform/platform-api/src/com/intellij/openapi/vfs/LocalFileSystem.java b/platform/platform-api/src/com/intellij/openapi/vfs/LocalFileSystem.java
index 7fcb84ad4dc5..84f83a789d62 100644
--- a/platform/platform-api/src/com/intellij/openapi/vfs/LocalFileSystem.java
+++ b/platform/platform-api/src/com/intellij/openapi/vfs/LocalFileSystem.java
@@ -50,7 +50,9 @@ public abstract class LocalFileSystem extends NewVirtualFileSystem {
   public abstract void refreshFiles(@NotNull Iterable<? extends VirtualFile> files, boolean async, boolean recursive, @Nullable Runnable onFinish);
 
   public interface WatchRequest {
-    @NotNull @SystemIndependent String getRootPath();
+    @NotNull
+    @SystemIndependent
+    String getRootPath();
     boolean isToWatchRecursively();
   }
 
@@ -73,10 +75,8 @@ public abstract class LocalFileSystem extends NewVirtualFileSystem {
     }
   }
 
-  public void removeWatchedRoot(@Nullable WatchRequest watchRequest) {
-    if (watchRequest != null) {
-      removeWatchedRoots(singleton(watchRequest));
-    }
+  public void removeWatchedRoot(@NotNull WatchRequest watchRequest) {
+    removeWatchedRoots(singleton(watchRequest));
   }
 
   public void removeWatchedRoots(@NotNull Collection<? extends WatchRequest> watchRequests) {
diff --git a/platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemImpl.java b/platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemImpl.java
index ec71a8e10310..b9a8a54702b2 100644
--- a/platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemImpl.java
+++ b/platform/platform-impl/src/com/intellij/openapi/vfs/impl/local/LocalFileSystemImpl.java
@@ -43,13 +43,14 @@ public final class LocalFileSystemImpl extends LocalFileSystemBase implements Di
     private final boolean myWatchRecursively;
     private boolean myDominated;
 
-    WatchRequestImpl(@SystemDependent String rootPath, boolean watchRecursively) {
+    WatchRequestImpl(@SystemDependent @NotNull String rootPath, boolean watchRecursively) {
       myFSRootPath = rootPath;
       myWatchRecursively = watchRecursively;
     }
 
+    @NotNull
     @Override
-    public @NotNull @SystemIndependent String getRootPath() {
+    public @SystemIndependent String getRootPath() {
       return FileUtil.toSystemIndependentName(myFSRootPath);
     }
 
@@ -89,6 +90,7 @@ public final class LocalFileSystemImpl extends LocalFileSystemBase implements Di
     myWatcher.dispose();
   }
 
+  @NotNull
   private List<WatchRequestImpl> normalizeRootsForRefresh() {
     List<WatchRequestImpl> result = new ArrayList<>();
 
@@ -168,14 +170,14 @@ public final class LocalFileSystemImpl extends LocalFileSystemBase implements Di
     return parts;
   }
 
-  private static void visitTree(TreeNode rootNode, Consumer<? super TreeNode> consumer) {
+  private static void visitTree(@NotNull TreeNode rootNode, @NotNull Consumer<? super TreeNode> consumer) {
     for (TreeNode node : rootNode.nodes.values()) {
       consumer.consume(node);
       visitTree(node, consumer);
     }
   }
 
-  private boolean isAlreadyWatched(final WatchRequestImpl request) {
+  private boolean isAlreadyWatched(@NotNull WatchRequestImpl request) {
     if (myNormalizedTree == null) {
       normalizeRootsForRefresh();
     }
@@ -206,7 +208,7 @@ public final class LocalFileSystemImpl extends LocalFileSystemBase implements Di
     }
   }
 
-  private void markPathsDirty(Iterable<String> dirtyPaths) {
+  private void markPathsDirty(@NotNull Iterable<String> dirtyPaths) {
     for (String dirtyPath : dirtyPaths) {
       VirtualFile file = findFileByPathIfCached(dirtyPath);
       if (file instanceof NewVirtualFile) {
@@ -215,7 +217,7 @@ public final class LocalFileSystemImpl extends LocalFileSystemBase implements Di
     }
   }
 
-  private void markFlatDirsDirty(Iterable<String> dirtyPaths) {
+  private void markFlatDirsDirty(@NotNull Iterable<String> dirtyPaths) {
     for (String dirtyPath : dirtyPaths) {
       Pair<NewVirtualFile, NewVirtualFile> pair = VfsImplUtil.findCachedFileByPath(this, dirtyPath);
       if (pair.first != null) {
@@ -230,7 +232,7 @@ public final class LocalFileSystemImpl extends LocalFileSystemBase implements Di
     }
   }
 
-  private void markRecursiveDirsDirty(Iterable<String> dirtyPaths) {
+  private void markRecursiveDirsDirty(@NotNull Iterable<String> dirtyPaths) {
     for (String dirtyPath : dirtyPaths) {
       Pair<NewVirtualFile, NewVirtualFile> pair = VfsImplUtil.findCachedFileByPath(this, dirtyPath);
       if (pair.first != null) {
@@ -270,7 +272,8 @@ public final class LocalFileSystemImpl extends LocalFileSystemBase implements Di
     recursiveRoots = ObjectUtils.notNull(recursiveRoots, Collections.emptyList());
     flatRoots = ObjectUtils.notNull(flatRoots, Collections.emptyList());
 
-    Set<String> recursiveWatches = new HashSet<>(), flatWatches = new HashSet<>();
+    Set<String> recursiveWatches = new HashSet<>();
+    Set<String> flatWatches = new HashSet<>();
     for (LocalFileSystem.WatchRequest watch : watchRequests) {
       (watch.isToWatchRecursively() ? recursiveWatches : flatWatches).add(watch.getRootPath());
     }
@@ -281,8 +284,8 @@ public final class LocalFileSystemImpl extends LocalFileSystemBase implements Di
 
     Set<WatchRequest> result = new HashSet<>();
     synchronized (myLock) {
-      boolean update = doAddRootsToWatch(recursiveRoots, flatRoots, result) |
-                       doRemoveWatchedRoots(watchRequests);
+      boolean update = doAddRootsToWatch(recursiveRoots, flatRoots, result);
+      update |= doRemoveWatchedRoots(watchRequests);
       if (update) {
         myNormalizedTree = null;
         setUpFileWatcher();
@@ -291,14 +294,14 @@ public final class LocalFileSystemImpl extends LocalFileSystemBase implements Di
     return result;
   }
 
-  private boolean doAddRootsToWatch(Collection<String> recursiveRoots, Collection<String> flatRoots, Set<? super WatchRequest> result) {
+  private boolean doAddRootsToWatch(@NotNull Collection<String> recursiveRoots, @NotNull Collection<String> flatRoots, @NotNull Set<? super WatchRequest> result) {
     boolean update = false;
     for (String root : recursiveRoots) update |= watch(root, true, result);
     for (String root : flatRoots) update |= watch(root, false, result);
     return update;
   }
 
-  private boolean watch(String rootPath, boolean recursively, Set<? super WatchRequest> result) {
+  private boolean watch(@NotNull String rootPath, boolean recursively, @NotNull Set<? super WatchRequest> result) {
     int index = rootPath.indexOf(JarFileSystem.JAR_SEPARATOR);
     if (index >= 0) rootPath = rootPath.substring(0, index);
 
@@ -315,7 +318,7 @@ public final class LocalFileSystemImpl extends LocalFileSystemBase implements Di
     return !request.myDominated;
   }
 
-  private boolean doRemoveWatchedRoots(Collection<? extends WatchRequest> watchRequests) {
+  private boolean doRemoveWatchedRoots(@NotNull Collection<? extends WatchRequest> watchRequests) {
     boolean update = false;
 
     for (WatchRequest watchRequest : watchRequests) {
diff --git a/plugins/cvs/cvs-plugin/src/com/intellij/cvsSupport2/application/CvsFileOperationsHandler.java b/plugins/cvs/cvs-plugin/src/com/intellij/cvsSupport2/application/CvsFileOperationsHandler.java
index 73912fe3b5d4..5a596dd4ee30 100644
--- a/plugins/cvs/cvs-plugin/src/com/intellij/cvsSupport2/application/CvsFileOperationsHandler.java
+++ b/plugins/cvs/cvs-plugin/src/com/intellij/cvsSupport2/application/CvsFileOperationsHandler.java
@@ -26,6 +26,7 @@ import com.intellij.openapi.vcs.ProjectLevelVcsManager;
 import com.intellij.openapi.vfs.LocalFileOperationsHandler;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.util.ThrowableConsumer;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.io.File;
@@ -45,11 +46,11 @@ public class CvsFileOperationsHandler implements LocalFileOperationsHandler {
   }
 
   @Override
-  public boolean delete(final VirtualFile file) throws IOException {
+  public boolean delete(@NotNull final VirtualFile file) throws IOException {
     return processDeletedFile(file);
   }
 
-  private boolean processDeletedFile(final VirtualFile file) throws IOException {
+  private boolean processDeletedFile(@NotNull VirtualFile file) throws IOException {
     if (myInternalDelete) return false;
     final AbstractVcs vcs = ProjectLevelVcsManager.getInstance(myProject).getVcsFor(file);
     if (vcs != CvsVcs2.getInstance(myProject)) return false;
@@ -82,18 +83,18 @@ public class CvsFileOperationsHandler implements LocalFileOperationsHandler {
   }
 
   @Override
-  public boolean move(final VirtualFile file, final VirtualFile toDir) throws IOException {
+  public boolean move(@NotNull final VirtualFile file, @NotNull final VirtualFile toDir) throws IOException {
     return doMoveRename(file, toDir, file.getName());
   }
 
   @Override
   @Nullable
-  public File copy(final VirtualFile file, final VirtualFile toDir, final String copyName) {
+  public File copy(@NotNull final VirtualFile file, @NotNull final VirtualFile toDir, @NotNull final String copyName) {
     return null;
   }
 
   @Override
-  public boolean rename(final VirtualFile file, final String newName) throws IOException {
+  public boolean rename(@NotNull final VirtualFile file, @NotNull final String newName) throws IOException {
     return doMoveRename(file, file.getParent(), newName);
   }
 
@@ -129,15 +130,15 @@ public class CvsFileOperationsHandler implements LocalFileOperationsHandler {
   }
 
   @Override
-  public boolean createFile(final VirtualFile dir, final String name) {
+  public boolean createFile(@NotNull final VirtualFile dir, @NotNull final String name) {
     return false;
   }
 
   @Override
-  public boolean createDirectory(final VirtualFile dir, final String name) {
+  public boolean createDirectory(@NotNull final VirtualFile dir, @NotNull final String name) {
     return false;
   }
 
   @Override
-  public void afterDone(final ThrowableConsumer<LocalFileOperationsHandler, IOException> invoker) {}
+  public void afterDone(@NotNull final ThrowableConsumer<LocalFileOperationsHandler, IOException> invoker) {}
 }
diff --git a/plugins/svn4idea/src/org/jetbrains/idea/svn/SvnFileSystemListener.java b/plugins/svn4idea/src/org/jetbrains/idea/svn/SvnFileSystemListener.java
index ddc9d6c27309..6ecfe6cb4bd8 100644
--- a/plugins/svn4idea/src/org/jetbrains/idea/svn/SvnFileSystemListener.java
+++ b/plugins/svn4idea/src/org/jetbrains/idea/svn/SvnFileSystemListener.java
@@ -57,7 +57,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
     @Nullable private final File myCopyFrom;
     private final boolean myRecursive;
 
-    AddedFileInfo(final VirtualFile dir, final String name, @Nullable final File copyFrom, boolean recursive) {
+    AddedFileInfo(@NotNull VirtualFile dir, @NotNull String name, @Nullable final File copyFrom, boolean recursive) {
       myDir = dir;
       myName = name;
       myCopyFrom = copyFrom;
@@ -70,7 +70,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
     private final File mySrc;
     private final File myDst;
 
-    private MovedFileInfo(final Project project, final File src, final File dst) {
+    private MovedFileInfo(@NotNull Project project, @NotNull File src, @NotNull File dst) {
       myProject = project;
       mySrc = src;
       myDst = dst;
@@ -114,6 +114,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
     return e instanceof SvnBindException && ((SvnBindException)e).contains(ErrorCode.ENTRY_EXISTS) ? createMoveTargetExistsError(e) : e;
   }
 
+  @NotNull
   private static VcsException createMoveTargetExistsError(@NotNull Exception e) {
     return new VcsException(Arrays.asList("Target of move operation is already under version control.",
                                           "Subversion move had not been performed. ", e.getMessage()));
@@ -121,7 +122,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
 
   @Override
   @Nullable
-  public File copy(final VirtualFile file, final VirtualFile toDir, final String copyName) {
+  public File copy(@NotNull final VirtualFile file, @NotNull final VirtualFile toDir, @NotNull final String copyName) {
     startOperation(file);
 
     SvnVcs vcs = getVCS(toDir);
@@ -158,7 +159,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
     return null;
   }
 
-  private boolean sameRoot(final SvnVcs vcs, final VirtualFile srcDir, final VirtualFile dstDir) {
+  private boolean sameRoot(@NotNull SvnVcs vcs, @NotNull VirtualFile srcDir, @NotNull VirtualFile dstDir) {
     final UUIDHelper helper = new UUIDHelper(vcs);
     final String srcUUID = helper.getRepositoryUUID(vcs.getProject(), srcDir);
     final String dstUUID = helper.getRepositoryUUID(vcs.getProject(), dstDir);
@@ -169,7 +170,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
   private class UUIDHelper {
     private final SvnVcs myVcs;
 
-    private UUIDHelper(final SvnVcs vcs) {
+    private UUIDHelper(@NotNull SvnVcs vcs) {
       myVcs = vcs;
     }
 
@@ -177,7 +178,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
      * passed dir must be under VC control (it is assumed)
      */
     @Nullable
-    public String getRepositoryUUID(final Project project, final VirtualFile dir) {
+    public String getRepositoryUUID(@NotNull Project project, @NotNull VirtualFile dir) {
       try {
         final Info info1 = new RepeatSvnActionThroughBusy() {
           @Override
@@ -206,7 +207,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
   }
 
   @Override
-  public boolean move(VirtualFile file, VirtualFile toDir) {
+  public boolean move(@NotNull VirtualFile file, @NotNull VirtualFile toDir) {
     startOperation(file);
 
     File srcFile = getIOFile(file);
@@ -237,7 +238,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
   }
 
   @Override
-  public boolean rename(VirtualFile file, String newName) {
+  public boolean rename(@NotNull VirtualFile file, @NotNull String newName) {
     startOperation(file);
 
     File srcFile = getIOFile(file);
@@ -254,7 +255,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
     return false;
   }
 
-  private boolean doMove(@NotNull SvnVcs vcs, final File src, final File dst) {
+  private boolean doMove(@NotNull SvnVcs vcs, @NotNull File src, @NotNull File dst) {
     try {
       final boolean isUndo = isUndo(vcs);
       final String list = isUndo ? null : SvnChangelistListener.getCurrentMapping(vcs, src);
@@ -399,14 +400,14 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
 
 
   @Override
-  public boolean createFile(VirtualFile dir, String name) {
+  public boolean createFile(@NotNull VirtualFile dir, @NotNull String name) {
     startOperation(dir);
 
     return createItem(dir, name, false, false);
   }
 
   @Override
-  public boolean createDirectory(VirtualFile dir, String name) {
+  public boolean createDirectory(@NotNull VirtualFile dir, @NotNull String name) {
     startOperation(dir);
 
     return createItem(dir, name, true, false);
@@ -427,7 +428,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
    * deleted: do nothing, return true (strange)
    */
   @Override
-  public boolean delete(VirtualFile file) {
+  public boolean delete(@NotNull VirtualFile file) {
     startOperation(file);
 
     final SvnVcs vcs = getVCS(file);
@@ -965,7 +966,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
   }
 
   @Nullable
-  private static SvnVcs getVCS(VirtualFile file) {
+  private static SvnVcs getVCS(@NotNull VirtualFile file) {
     Project[] projects = ProjectManager.getInstance().getOpenProjects();
     for (Project project : projects) {
       AbstractVcs vcs = ProjectLevelVcsManager.getInstance(project).getVcsFor(file);
@@ -977,7 +978,8 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
   }
 
 
-  private static File getIOFile(VirtualFile vf) {
+  @NotNull
+  private static File getIOFile(@NotNull VirtualFile vf) {
     return virtualToIoFile(vf).getAbsoluteFile();
   }
 
@@ -996,10 +998,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
     }
   }
 
-  private static boolean isUndo(SvnVcs vcs) {
-    if (vcs == null || vcs.getProject() == null) {
-      return false;
-    }
+  private static boolean isUndo(@NotNull SvnVcs vcs) {
     Project p = vcs.getProject();
     return UndoManager.getInstance(p).isUndoInProgress();
   }
@@ -1015,7 +1014,7 @@ public class SvnFileSystemListener implements LocalFileOperationsHandler, Dispos
   }
 
   @Override
-  public void afterDone(final ThrowableConsumer<LocalFileOperationsHandler, IOException> invoker) {
+  public void afterDone(@NotNull final ThrowableConsumer<LocalFileOperationsHandler, IOException> invoker) {
     if (!myIsInCommand && myGuessedProject != null) {
       commandFinished(myGuessedProject);
       myGuessedProject = null;