diff --git a/java/execution/openapi/src/com/intellij/execution/filters/ExceptionExFilterFactory.java b/java/execution/openapi/src/com/intellij/execution/filters/ExceptionExFilterFactory.java
index 722fb066ac1b..651bb76c445d 100644
--- a/java/execution/openapi/src/com/intellij/execution/filters/ExceptionExFilterFactory.java
+++ b/java/execution/openapi/src/com/intellij/execution/filters/ExceptionExFilterFactory.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2012 JetBrains s.r.o.
+ * Copyright 2000-2015 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.
@@ -62,10 +62,10 @@ public class ExceptionExFilterFactory implements ExceptionFilterFactory {
     }
 
     @Override
-    public void applyHeavyFilter(final Document copiedFragment,
+    public void applyHeavyFilter(@NotNull final Document copiedFragment,
                                  final int startOffset,
                                  int startLineNumber,
-                                 final Consumer<AdditionalHighlight> consumer) {
+                                 @NotNull final Consumer<AdditionalHighlight> consumer) {
       Map<String, Trinity<TextRange, TextRange, TextRange>> visited = new THashMap<String, Trinity<TextRange, TextRange, TextRange>>();
       final Trinity<TextRange, TextRange, TextRange> emptyInfo = Trinity.create(null, null, null);
 
@@ -110,6 +110,7 @@ public class ExceptionExFilterFactory implements ExceptionFilterFactory {
         int off = startOffset + lineStartOffset;
         final Color color = UIUtil.getInactiveTextColor();
         consumer.consume(new AdditionalHighlight(off + info.first.getStartOffset(), off + info.second.getEndOffset()) {
+          @NotNull
           @Override
           public TextAttributes getTextAttributes(@Nullable TextAttributes source) {
             return new TextAttributes(null, null, color, EffectType.BOLD_DOTTED_LINE, Font.PLAIN);
@@ -118,6 +119,7 @@ public class ExceptionExFilterFactory implements ExceptionFilterFactory {
       }
     }
 
+    @NotNull
     @Override
     public String getUpdateMessage() {
       return "Highlighting try blocks...";
diff --git a/java/idea-ui/src/com/intellij/ide/util/projectWizard/ProjectJdkForModuleStep.java b/java/idea-ui/src/com/intellij/ide/util/projectWizard/ProjectJdkForModuleStep.java
index 533ca0d30619..42f47c9d2344 100644
--- a/java/idea-ui/src/com/intellij/ide/util/projectWizard/ProjectJdkForModuleStep.java
+++ b/java/idea-ui/src/com/intellij/ide/util/projectWizard/ProjectJdkForModuleStep.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2013 JetBrains s.r.o.
+ * Copyright 2000-2015 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.
@@ -32,6 +32,7 @@ import com.intellij.openapi.ui.Messages;
 import com.intellij.openapi.ui.MultiLineLabelUI;
 import com.intellij.util.Consumer;
 import com.intellij.util.ui.UIUtil;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
@@ -47,7 +48,7 @@ import java.awt.event.ActionListener;
  */
 public class ProjectJdkForModuleStep extends ModuleWizardStep {
   private final JdkChooserPanel myJdkChooser;
-  private final JPanel myPanel;
+  @NotNull private final JPanel myPanel;
   private final WizardContext myContext;
   private final SdkType myType;
   private boolean myInitialized = false;
diff --git a/java/idea-ui/src/com/intellij/openapi/projectRoots/ui/SdkEditor.java b/java/idea-ui/src/com/intellij/openapi/projectRoots/ui/SdkEditor.java
index ce4a91952281..17a52d249a70 100644
--- a/java/idea-ui/src/com/intellij/openapi/projectRoots/ui/SdkEditor.java
+++ b/java/idea-ui/src/com/intellij/openapi/projectRoots/ui/SdkEditor.java
@@ -172,7 +172,7 @@ public class SdkEditor implements Configurable, Place.Navigator {
     });
   }
 
-  protected boolean showTabForType(OrderRootType type) {
+  protected boolean showTabForType(@NotNull OrderRootType type) {
     return ((SdkType) mySdk.getSdkType()).isRootTypeApplicable(type);
   }
 
diff --git a/java/java-impl/src/com/intellij/openapi/projectRoots/impl/JavaSdkImpl.java b/java/java-impl/src/com/intellij/openapi/projectRoots/impl/JavaSdkImpl.java
index 2ac0a1c83bd3..8a5d7631cb94 100644
--- a/java/java-impl/src/com/intellij/openapi/projectRoots/impl/JavaSdkImpl.java
+++ b/java/java-impl/src/com/intellij/openapi/projectRoots/impl/JavaSdkImpl.java
@@ -100,6 +100,7 @@ public class JavaSdkImpl extends JavaSdk {
     });
   }
 
+  @NotNull
   @Override
   public String getPresentableName() {
     return ProjectBundle.message("sdk.java.name");
@@ -116,6 +117,7 @@ public class JavaSdkImpl extends JavaSdk {
     return "reference.project.structure.sdk.java";
   }
 
+  @NotNull
   @Override
   public Icon getIconForAddAction() {
     return AllIcons.General.AddJdk;
@@ -141,7 +143,7 @@ public class JavaSdkImpl extends JavaSdk {
   }
 
   @Override
-  public AdditionalDataConfigurable createAdditionalDataConfigurable(SdkModel sdkModel, SdkModificator sdkModificator) {
+  public AdditionalDataConfigurable createAdditionalDataConfigurable(@NotNull SdkModel sdkModel, @NotNull SdkModificator sdkModificator) {
     return null;
   }
 
@@ -280,6 +282,7 @@ public class JavaSdkImpl extends JavaSdk {
     }
   }
 
+  @NotNull
   @Override
   public FileChooserDescriptor getHomeChooserDescriptor() {
     final FileChooserDescriptor baseDescriptor = super.getHomeChooserDescriptor();
@@ -299,8 +302,9 @@ public class JavaSdkImpl extends JavaSdk {
     return descriptor;
   }
 
+  @NotNull
   @Override
-  public String adjustSelectedSdkHome(String homePath) {
+  public String adjustSelectedSdkHome(@NotNull String homePath) {
     if (SystemInfo.isMac) {
       File home = new File(homePath, "/Home");
       if (home.exists()) return home.getPath();
@@ -621,7 +625,7 @@ public class JavaSdkImpl extends JavaSdk {
   }
 
   @Override
-  public boolean isRootTypeApplicable(OrderRootType type) {
+  public boolean isRootTypeApplicable(@NotNull OrderRootType type) {
     return type == OrderRootType.CLASSES ||
            type == OrderRootType.SOURCES ||
            type == JavadocOrderRootType.getInstance() ||
diff --git a/java/java-impl/src/com/intellij/openapi/vcs/contentAnnotation/VcsContentAnnotationExceptionFilter.java b/java/java-impl/src/com/intellij/openapi/vcs/contentAnnotation/VcsContentAnnotationExceptionFilter.java
index 83e237aa2eff..cb75f56902b0 100644
--- a/java/java-impl/src/com/intellij/openapi/vcs/contentAnnotation/VcsContentAnnotationExceptionFilter.java
+++ b/java/java-impl/src/com/intellij/openapi/vcs/contentAnnotation/VcsContentAnnotationExceptionFilter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2011 JetBrains s.r.o.
+ * Copyright 2000-2015 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.
@@ -71,6 +71,7 @@ public class VcsContentAnnotationExceptionFilter implements Filter, FilterMixin
       super(start, end);
     }
 
+    @NotNull
     @Override
     public TextAttributes getTextAttributes(@Nullable TextAttributes source) {
       EditorColorsScheme globalScheme = EditorColorsManager.getInstance().getGlobalScheme();
@@ -93,10 +94,10 @@ public class VcsContentAnnotationExceptionFilter implements Filter, FilterMixin
   }
 
   @Override
-  public void applyHeavyFilter(final Document copiedFragment,
+  public void applyHeavyFilter(@NotNull final Document copiedFragment,
                                int startOffset,
                                int startLineNumber,
-                               Consumer<AdditionalHighlight> consumer) {
+                               @NotNull Consumer<AdditionalHighlight> consumer) {
     VcsContentAnnotation vcsContentAnnotation = VcsContentAnnotationImpl.getInstance(myProject);
     final LocalChangesCorrector localChangesCorrector = new LocalChangesCorrector(myProject);
     Trinity<PsiClass, PsiFile, String> previousLineResult = null;
@@ -168,6 +169,7 @@ public class VcsContentAnnotationExceptionFilter implements Filter, FilterMixin
     }
   }
 
+  @NotNull
   @Override
   public String getUpdateMessage() {
     return "Checking recent changes...";
diff --git a/platform/lang-api/src/com/intellij/execution/filters/FilterMixin.java b/platform/lang-api/src/com/intellij/execution/filters/FilterMixin.java
index 059c6f65879f..da8fe5377d9e 100644
--- a/platform/lang-api/src/com/intellij/execution/filters/FilterMixin.java
+++ b/platform/lang-api/src/com/intellij/execution/filters/FilterMixin.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2011 JetBrains s.r.o.
+ * Copyright 2000-2015 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.
@@ -18,6 +18,7 @@ package com.intellij.execution.filters;
 import com.intellij.openapi.editor.Document;
 import com.intellij.openapi.editor.markup.TextAttributes;
 import com.intellij.util.Consumer;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 /**
@@ -28,15 +29,16 @@ import org.jetbrains.annotations.Nullable;
  */
 public interface FilterMixin {
   boolean shouldRunHeavy();
-  void applyHeavyFilter(Document copiedFragment, int startOffset, int startLineNumber, Consumer<AdditionalHighlight> consumer);
+  void applyHeavyFilter(@NotNull Document copiedFragment, int startOffset, int startLineNumber, @NotNull Consumer<AdditionalHighlight> consumer);
 
+  @NotNull
   String getUpdateMessage();
 
   abstract class AdditionalHighlight {
     private final int myStart;
     private final int myEnd;
 
-    public AdditionalHighlight(int start, int end) {
+    protected AdditionalHighlight(int start, int end) {
       myStart = start;
       myEnd = end;
     }
@@ -49,6 +51,7 @@ public interface FilterMixin {
       return myEnd;
     }
 
+    @NotNull
     public abstract TextAttributes getTextAttributes(@Nullable final TextAttributes source);
   }
 }
diff --git a/platform/lang-api/src/com/intellij/openapi/projectRoots/SdkType.java b/platform/lang-api/src/com/intellij/openapi/projectRoots/SdkType.java
index 0411e16894ca..47d5fa15f89d 100644
--- a/platform/lang-api/src/com/intellij/openapi/projectRoots/SdkType.java
+++ b/platform/lang-api/src/com/intellij/openapi/projectRoots/SdkType.java
@@ -71,7 +71,8 @@ public abstract class SdkType implements SdkTypeId {
    * @param homePath the path selected in the file chooser.
    * @return the path to be used as the SDK home.
    */
-  public String adjustSelectedSdkHome(String homePath) {
+  @NotNull
+  public String adjustSelectedSdkHome(@NotNull String homePath) {
     return homePath;
   }
 
@@ -92,7 +93,7 @@ public abstract class SdkType implements SdkTypeId {
 
   public void setupSdkPaths(@NotNull Sdk sdk) {}
 
-  public boolean setupSdkPaths(final Sdk sdk, final SdkModel sdkModel) {
+  public boolean setupSdkPaths(@NotNull Sdk sdk, @NotNull SdkModel sdkModel) {
     setupSdkPaths(sdk);
     return true;
   }
@@ -101,7 +102,7 @@ public abstract class SdkType implements SdkTypeId {
    * @return Configurable object for the sdk's additional data or null if not applicable
    */
   @Nullable
-  public abstract AdditionalDataConfigurable createAdditionalDataConfigurable(SdkModel sdkModel, SdkModificator sdkModificator);
+  public abstract AdditionalDataConfigurable createAdditionalDataConfigurable(@NotNull SdkModel sdkModel, @NotNull SdkModificator sdkModificator);
 
   @Nullable
   public SdkAdditionalData loadAdditionalData(Element additional) {
@@ -120,6 +121,7 @@ public abstract class SdkType implements SdkTypeId {
     return myName;
   }
 
+  @NotNull
   public abstract String getPresentableName();
 
   public Icon getIcon() {
@@ -131,6 +133,7 @@ public abstract class SdkType implements SdkTypeId {
     return "preferences.jdks";
   }
 
+  @NotNull
   public Icon getIconForAddAction() {
     return IconUtil.getAddIcon();
   }
@@ -157,6 +160,7 @@ public abstract class SdkType implements SdkTypeId {
     return getName();
   }
 
+  @NotNull
   public FileChooserDescriptor getHomeChooserDescriptor() {
     final FileChooserDescriptor descriptor = new FileChooserDescriptor(false, true, false, false, false, false) {
       @Override
@@ -181,6 +185,7 @@ public abstract class SdkType implements SdkTypeId {
   }
 
 
+  @NotNull
   public String getHomeFieldLabel() {
     return ProjectBundle.message("sdk.configure.type.home.path", getPresentableName());
   }
@@ -190,6 +195,7 @@ public abstract class SdkType implements SdkTypeId {
     return null;
   }
 
+  @NotNull
   public static SdkType[] getAllTypes() {
     List<SdkType> allTypes = new ArrayList<SdkType>();
     Collections.addAll(allTypes, ApplicationManager.getApplication().getComponents(SdkType.class));
@@ -197,7 +203,8 @@ public abstract class SdkType implements SdkTypeId {
     return allTypes.toArray(new SdkType[allTypes.size()]);
   }
 
-  public static <T extends SdkType> T findInstance(final Class<T> sdkTypeClass) {
+  @NotNull
+  public static <T extends SdkType> T findInstance(@NotNull Class<T> sdkTypeClass) {
     for (SdkType sdkType : Extensions.getExtensions(EP_NAME)) {
       if (sdkTypeClass.equals(sdkType.getClass())) {
         //noinspection unchecked
@@ -208,7 +215,7 @@ public abstract class SdkType implements SdkTypeId {
     return null;
   }
 
-  public boolean isRootTypeApplicable(final OrderRootType type) {
+  public boolean isRootTypeApplicable(@NotNull OrderRootType type) {
     return true;
   }
 
@@ -232,7 +239,7 @@ public abstract class SdkType implements SdkTypeId {
    * @param sdkCreatedCallback the callback to which the created SDK is passed.
    * @since 12.0
    */
-  public void showCustomCreateUI(SdkModel sdkModel, JComponent parentComponent, Consumer<Sdk> sdkCreatedCallback) {
+  public void showCustomCreateUI(@NotNull SdkModel sdkModel, @NotNull JComponent parentComponent, @NotNull Consumer<Sdk> sdkCreatedCallback) {
   }
 
   /**
@@ -248,7 +255,7 @@ public abstract class SdkType implements SdkTypeId {
     return homeDir != null && homeDir.isValid();
   }
 
-  public String sdkPath(VirtualFile homePath) {
+  public String sdkPath(@NotNull VirtualFile homePath) {
     return homePath.getPath();
   }
 }
diff --git a/platform/lang-api/src/com/intellij/openapi/projectRoots/SimpleJavaSdkType.java b/platform/lang-api/src/com/intellij/openapi/projectRoots/SimpleJavaSdkType.java
index 9db9794a9b9f..dac1d63ce4dd 100644
--- a/platform/lang-api/src/com/intellij/openapi/projectRoots/SimpleJavaSdkType.java
+++ b/platform/lang-api/src/com/intellij/openapi/projectRoots/SimpleJavaSdkType.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2009 JetBrains s.r.o.
+ * Copyright 2000-2015 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.
@@ -45,13 +45,14 @@ public class SimpleJavaSdkType extends SdkType implements JavaSdkType {
     return jdk;
   }
 
+  @NotNull
   @Override
   public String getPresentableName() {
     return ProjectBundle.message("sdk.java.name");
   }
 
   @Override
-  public AdditionalDataConfigurable createAdditionalDataConfigurable(SdkModel sdkModel, SdkModificator sdkModificator) {
+  public AdditionalDataConfigurable createAdditionalDataConfigurable(@NotNull SdkModel sdkModel, @NotNull SdkModificator sdkModificator) {
     return null;
   }
 
diff --git a/platform/lang-api/src/com/intellij/openapi/projectRoots/impl/UnknownSdkType.java b/platform/lang-api/src/com/intellij/openapi/projectRoots/impl/UnknownSdkType.java
index 2b06e87d833d..2dc8266bf5f2 100644
--- a/platform/lang-api/src/com/intellij/openapi/projectRoots/impl/UnknownSdkType.java
+++ b/platform/lang-api/src/com/intellij/openapi/projectRoots/impl/UnknownSdkType.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2009 JetBrains s.r.o.
+ * Copyright 2000-2015 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.
@@ -71,7 +71,7 @@ public class UnknownSdkType extends SdkType{
   }
 
   @Override
-  public AdditionalDataConfigurable createAdditionalDataConfigurable(SdkModel sdkModel, SdkModificator sdkModificator) {
+  public AdditionalDataConfigurable createAdditionalDataConfigurable(@NotNull SdkModel sdkModel, @NotNull SdkModificator sdkModificator) {
     return null;
   }
 
@@ -91,6 +91,7 @@ public class UnknownSdkType extends SdkType{
   public void saveAdditionalData(@NotNull SdkAdditionalData additionalData, @NotNull Element additional) {
   }
 
+  @NotNull
   @Override
   public String getPresentableName() {
     return ProjectBundle.message("sdk.unknown.name");
diff --git a/platform/lang-impl/src/com/intellij/openapi/projectRoots/impl/DependentSdkType.java b/platform/lang-impl/src/com/intellij/openapi/projectRoots/impl/DependentSdkType.java
index 926813fac514..0dd06d060f0e 100644
--- a/platform/lang-impl/src/com/intellij/openapi/projectRoots/impl/DependentSdkType.java
+++ b/platform/lang-impl/src/com/intellij/openapi/projectRoots/impl/DependentSdkType.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2012 JetBrains s.r.o.
+ * Copyright 2000-2015 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.
@@ -24,6 +24,7 @@ import com.intellij.openapi.util.Ref;
 import com.intellij.util.Consumer;
 import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NonNls;
+import org.jetbrains.annotations.NotNull;
 
 import javax.swing.*;
 import java.util.Arrays;
@@ -60,7 +61,7 @@ public abstract class DependentSdkType extends SdkType {
   }
 
   @Override
-  public void showCustomCreateUI(final SdkModel sdkModel, JComponent parentComponent, final Consumer<Sdk> sdkCreatedCallback) {
+  public void showCustomCreateUI(@NotNull final SdkModel sdkModel, @NotNull JComponent parentComponent, @NotNull final Consumer<Sdk> sdkCreatedCallback) {
     if (!checkDependency(sdkModel)) {
       if (Messages.showOkCancelDialog(parentComponent, getUnsatisfiedDependencyMessage(), "Cannot Create SDK", Messages.getWarningIcon()) != Messages.OK) {
         return;
diff --git a/platform/lang-impl/src/com/intellij/openapi/projectRoots/impl/SdkConfigurationUtil.java b/platform/lang-impl/src/com/intellij/openapi/projectRoots/impl/SdkConfigurationUtil.java
index a83adffa083a..f78d871a7280 100644
--- a/platform/lang-impl/src/com/intellij/openapi/projectRoots/impl/SdkConfigurationUtil.java
+++ b/platform/lang-impl/src/com/intellij/openapi/projectRoots/impl/SdkConfigurationUtil.java
@@ -135,8 +135,10 @@ public class SdkConfigurationUtil {
   }
 
   @Nullable
-  public static Sdk setupSdk(final Sdk[] allSdks,
-                             final VirtualFile homeDir, final SdkType sdkType, final boolean silent,
+  public static Sdk setupSdk(@NotNull Sdk[] allSdks,
+                             @NotNull VirtualFile homeDir,
+                             final SdkType sdkType,
+                             final boolean silent,
                              @Nullable final SdkAdditionalData additionalData,
                              @Nullable final String customSdkSuggestedName) {
     final List<Sdk> sdksList = Arrays.asList(allSdks);
diff --git a/platform/lang-impl/src/com/intellij/openapi/roots/ui/configuration/projectRoot/ProjectSdksModel.java b/platform/lang-impl/src/com/intellij/openapi/roots/ui/configuration/projectRoot/ProjectSdksModel.java
index bc464fa20f29..350ed36a7220 100644
--- a/platform/lang-impl/src/com/intellij/openapi/roots/ui/configuration/projectRoot/ProjectSdksModel.java
+++ b/platform/lang-impl/src/com/intellij/openapi/roots/ui/configuration/projectRoot/ProjectSdksModel.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2015 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.
@@ -37,7 +37,9 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
 
 /**
  * @author anna
@@ -238,13 +240,13 @@ public class ProjectSdksModel implements SdkModel {
     }
   }
 
-  public void createAddActions(DefaultActionGroup group, final JComponent parent, final Consumer<Sdk> updateTree) {
+  public void createAddActions(@NotNull DefaultActionGroup group, @NotNull JComponent parent, @NotNull Consumer<Sdk> updateTree) {
     createAddActions(group, parent, updateTree, null);
   }
 
-  public void createAddActions(DefaultActionGroup group,
-                               final JComponent parent,
-                               final Consumer<Sdk> updateTree,
+  public void createAddActions(@NotNull DefaultActionGroup group,
+                               @NotNull final JComponent parent,
+                               @NotNull final Consumer<Sdk> updateTree,
                                @Nullable Condition<SdkTypeId> filter) {
     final SdkType[] types = SdkType.getAllTypes();
     for (final SdkType type : types) {
@@ -259,7 +261,7 @@ public class ProjectSdksModel implements SdkModel {
     }
   }
 
-  public void doAdd(JComponent parent, final SdkType type, final Consumer<Sdk> callback) {
+  public void doAdd(@NotNull JComponent parent, @NotNull final SdkType type, @NotNull final Consumer<Sdk> callback) {
     myModified = true;
     if (type.supportsCustomCreateUI()) {
       type.showCustomCreateUI(this, parent, new Consumer<Sdk>() {
diff --git a/platform/util/src/com/intellij/util/xmlb/XmlSerializer.java b/platform/util/src/com/intellij/util/xmlb/XmlSerializer.java
index e13c122d9aa3..4d45fed53452 100644
--- a/platform/util/src/com/intellij/util/xmlb/XmlSerializer.java
+++ b/platform/util/src/com/intellij/util/xmlb/XmlSerializer.java
@@ -63,7 +63,7 @@ public class XmlSerializer {
 
   @Nullable
   @SuppressWarnings({"unchecked"})
-  public static <T> T deserialize(Element element, Class<T> aClass) throws XmlSerializationException {
+  public static <T> T deserialize(@NotNull Element element, @NotNull Class<T> aClass) throws XmlSerializationException {
     try {
       return (T)XmlSerializerImpl.getBinding(aClass).deserialize(null, element);
     }
diff --git a/plugins/devkit/src/projectRoots/IdeaJdk.java b/plugins/devkit/src/projectRoots/IdeaJdk.java
index b4b268ca339c..1fc41ca634ea 100644
--- a/plugins/devkit/src/projectRoots/IdeaJdk.java
+++ b/plugins/devkit/src/projectRoots/IdeaJdk.java
@@ -80,6 +80,7 @@ public class IdeaJdk extends JavaDependentSdkType implements JavaSdkType {
     return "reference.project.structure.sdk.idea";
   }
 
+  @NotNull
   public Icon getIconForAddAction() {
     return ADD_SDK;
   }
@@ -88,8 +89,9 @@ public class IdeaJdk extends JavaDependentSdkType implements JavaSdkType {
     return PathManager.getHomePath().replace(File.separatorChar, '/');
   }
 
+  @NotNull
   @Override
-  public String adjustSelectedSdkHome(String homePath) {
+  public String adjustSelectedSdkHome(@NotNull String homePath) {
     if (SystemInfo.isMac) {
       File home = new File(homePath, "Contents");
       if (home.exists()) return home.getPath();
@@ -209,7 +211,7 @@ public class IdeaJdk extends JavaDependentSdkType implements JavaSdkType {
   }
 
 
-  public boolean setupSdkPaths(final Sdk sdk, SdkModel sdkModel) {
+  public boolean setupSdkPaths(@NotNull final Sdk sdk, @NotNull SdkModel sdkModel) {
     final Sandbox additionalData = (Sandbox)sdk.getSdkAdditionalData();
     if (additionalData != null) {
       additionalData.cleanupWatchedRoots();
@@ -418,7 +420,7 @@ public class IdeaJdk extends JavaDependentSdkType implements JavaSdkType {
     return wasSmthAdded;
   }
 
-  public AdditionalDataConfigurable createAdditionalDataConfigurable(final SdkModel sdkModel, SdkModificator sdkModificator) {
+  public AdditionalDataConfigurable createAdditionalDataConfigurable(@NotNull final SdkModel sdkModel, @NotNull SdkModificator sdkModificator) {
     return new IdeaJdkConfigurable(sdkModel, sdkModificator);
   }
 
@@ -465,6 +467,7 @@ public class IdeaJdk extends JavaDependentSdkType implements JavaSdkType {
     return sandbox;
   }
 
+  @NotNull
   public String getPresentableName() {
     return DevKitBundle.message("sdk.title");
   }
@@ -481,7 +484,7 @@ public class IdeaJdk extends JavaDependentSdkType implements JavaSdkType {
   }
 
   @Override
-  public boolean isRootTypeApplicable(OrderRootType type) {
+  public boolean isRootTypeApplicable(@NotNull OrderRootType type) {
     return type == OrderRootType.CLASSES ||
            type == OrderRootType.SOURCES ||
            type == JavadocOrderRootType.getInstance() ||
diff --git a/python/src/com/jetbrains/python/sdk/PythonSdkType.java b/python/src/com/jetbrains/python/sdk/PythonSdkType.java
index 1126170d92bb..3cf06f947ad1 100644
--- a/python/src/com/jetbrains/python/sdk/PythonSdkType.java
+++ b/python/src/com/jetbrains/python/sdk/PythonSdkType.java
@@ -135,6 +135,7 @@ public class PythonSdkType extends SdkType {
     return "reference.project.structure.sdk.python";
   }
 
+  @NotNull
   public Icon getIconForAddAction() {
     return PythonFileType.INSTANCE.getIcon();
   }
@@ -264,6 +265,7 @@ public class PythonSdkType extends SdkType {
     return isRemote(findSdkByPath(sdkPath));
   }
 
+  @NotNull
   @Override
   public FileChooserDescriptor getHomeChooserDescriptor() {
     final boolean isWindows = SystemInfo.isWindows;
@@ -302,7 +304,7 @@ public class PythonSdkType extends SdkType {
     return true;
   }
 
-  public void showCustomCreateUI(SdkModel sdkModel, final JComponent parentComponent, final Consumer<Sdk> sdkCreatedCallback) {
+  public void showCustomCreateUI(@NotNull SdkModel sdkModel, @NotNull final JComponent parentComponent, @NotNull final Consumer<Sdk> sdkCreatedCallback) {
     Project project = CommonDataKeys.PROJECT.getData(DataManager.getInstance().getDataContext(parentComponent));
     final PointerInfo pointerInfo = MouseInfo.getPointerInfo();
     if (pointerInfo == null) return;
@@ -456,7 +458,7 @@ public class PythonSdkType extends SdkType {
   }
 
   @Nullable
-  public AdditionalDataConfigurable createAdditionalDataConfigurable(final SdkModel sdkModel, final SdkModificator sdkModificator) {
+  public AdditionalDataConfigurable createAdditionalDataConfigurable(@NotNull final SdkModel sdkModel, @NotNull final SdkModificator sdkModificator) {
     return null;
   }
 
@@ -482,13 +484,14 @@ public class PythonSdkType extends SdkType {
     return path.contains(SKELETON_DIR_NAME);
   }
 
+  @NotNull
   @NonNls
   public String getPresentableName() {
     return "Python SDK";
   }
 
   @Override
-  public String sdkPath(VirtualFile homePath) {
+  public String sdkPath(@NotNull VirtualFile homePath) {
     String path = super.sdkPath(homePath);
     PythonSdkFlavor flavor = PythonSdkFlavor.getFlavor(path);
     if (flavor != null) {
@@ -520,7 +523,7 @@ public class PythonSdkType extends SdkType {
   }
 
   @Override
-  public boolean setupSdkPaths(Sdk sdk, SdkModel sdkModel) {
+  public boolean setupSdkPaths(@NotNull Sdk sdk, @NotNull SdkModel sdkModel) {
     return true;  // run setupSdkPaths only once (from PythonSdkDetailsStep). Skip this from showCustomCreateUI
   }
 
@@ -934,7 +937,7 @@ public class PythonSdkType extends SdkType {
     return LanguageLevel.getDefault();
   }
 
-  public boolean isRootTypeApplicable(final OrderRootType type) {
+  public boolean isRootTypeApplicable(@NotNull final OrderRootType type) {
     return type == OrderRootType.CLASSES;
   }