FacetEditorTab#createComponent annotated as @NotNull

platform/lang-api/src/com/intellij/facet/ui/FacetEditorTab.java

@@ -31,6 +31,9 @@ import javax.swing.*;
  * @author nik
  */
 public abstract class FacetEditorTab implements Configurable {
+  @NotNull
+  @Override
+  public abstract JComponent createComponent();
 
   @Override
   @Nullable

platform/lang-impl/src/com/intellij/facet/impl/invalid/InvalidFacetEditor.java

@@ -20,6 +20,7 @@ import com.intellij.facet.ui.FacetEditorTab;
 import com.intellij.icons.AllIcons;
 import com.intellij.openapi.ui.ex.MultiLineLabel;
 import org.jetbrains.annotations.Nls;
+import org.jetbrains.annotations.NotNull;
 
 import javax.swing.*;
 
@@ -51,6 +52,7 @@ public class InvalidFacetEditor extends FacetEditorTab {
     return myIgnoreCheckBox;
   }
 
+  @NotNull
   @Override
   public JComponent createComponent() {
     myIconLabel.setIcon(AllIcons.RunConfigurations.ConfigurationWarning);

plugins/google-app-engine/source/com/intellij/appengine/facet/AppEngineFacetEditor.java

@@ -105,6 +105,7 @@ public class AppEngineFacetEditor extends FacetEditorTab {
     return "Google App Engine";
   }
 
+  @NotNull
   public JComponent createComponent() {
     mySdkEditorPanel.add(BorderLayout.CENTER, mySdkEditor.getMainComponent());
     return myMainPanel;

python/pluginSrc/com/jetbrains/python/facet/PythonSdkEditorTab.java

@@ -23,6 +23,7 @@ import com.intellij.openapi.projectRoots.Sdk;
 import com.intellij.openapi.util.Disposer;
 import com.intellij.util.messages.MessageBusConnection;
 import org.jetbrains.annotations.Nls;
+import org.jetbrains.annotations.NotNull;
 
 import javax.swing.*;
 
@@ -63,6 +64,7 @@ public class PythonSdkEditorTab extends FacetEditorTab {
     return "Python SDK";
   }
 
+  @NotNull
   public JComponent createComponent() {
     return myMainPanel;
   }

python/src/com/jetbrains/python/buildout/BuildoutFacetConfiguration.java

@@ -26,6 +26,7 @@ import com.intellij.openapi.util.JDOMExternalizerUtil;
 import com.intellij.openapi.util.WriteExternalException;
 import org.jdom.Element;
 import org.jetbrains.annotations.Nls;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import javax.swing.*;
@@ -102,6 +103,7 @@ public class BuildoutFacetConfiguration implements FacetConfiguration {
       return "Buildout";
     }
 
+    @NotNull
     @Override
     public JComponent createComponent() {
       return myPanel;