some methods returning arrays marked notnull

RegExpSupport/src/org/intellij/lang/regexp/RegExpBraceMatcher.java

@@ -23,6 +23,7 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 public class RegExpBraceMatcher implements PairedBraceMatcher {
+  @NotNull
   @Override
   public BracePair[] getPairs() {
     return new BracePair[]{

java/java-analysis-impl/src/com/intellij/codeInsight/guess/GuessManager.java

@@ -31,8 +31,10 @@ public abstract class GuessManager {
     return ServiceManager.getService(project, GuessManager.class);
   }
 
+  @NotNull
   public abstract PsiType[] guessContainerElementType(PsiExpression containerExpr, TextRange rangeToIgnore);
 
+  @NotNull
   public abstract PsiType[] guessTypeToCast(PsiExpression expr);
 
   @NotNull 

java/java-analysis-impl/src/com/intellij/codeInsight/guess/impl/GuessManagerImpl.java

@@ -79,6 +79,7 @@ public class GuessManagerImpl extends GuessManager {
     myProject = project;
   }
 
+  @NotNull
   @Override
   public PsiType[] guessContainerElementType(PsiExpression containerExpr, TextRange rangeToIgnore) {
     HashSet<PsiType> typesSet = new HashSet<>();
@@ -117,6 +118,7 @@ public class GuessManagerImpl extends GuessManager {
     return null;
   }
 
+  @NotNull
   @Override
   public PsiType[] guessTypeToCast(PsiExpression expr) { //TODO : make better guess based on control flow
     LinkedHashSet<PsiType> types = new LinkedHashSet<>();

java/java-analysis-impl/src/com/intellij/codeInspection/RedundantSuppressInspectionBase.java

@@ -115,6 +115,7 @@ public class RedundantSuppressInspectionBase extends GlobalInspectionTool {
   }
 
   @NotNull
+  @Nullable
   public ProblemDescriptor[] checkElement(@NotNull final PsiElement psiElement, @NotNull final InspectionManager manager) {
     final Map<PsiElement, Collection<String>> suppressedScopes = new THashMap<>();
     psiElement.accept(new JavaRecursiveElementWalkingVisitor() {
@@ -296,6 +297,7 @@ public class RedundantSuppressInspectionBase extends GlobalInspectionTool {
     return new GlobalInspectionContextBase(file.getProject());
   }
 
+  @NotNull
   protected InspectionToolWrapper[] getInspectionTools(PsiElement psiElement, @NotNull InspectionManager manager) {
     // todo for what we create modifiable model here?
     return new InspectionProfileModifiableModel(InspectionProjectProfileManager.getInstance(manager.getProject()).getCurrentProfile()).getInspectionTools(psiElement);

java/java-analysis-impl/src/com/intellij/codeInspection/bytecodeAnalysis/NullableMethodAnalysis.java

@@ -18,6 +18,7 @@ package com.intellij.codeInspection.bytecodeAnalysis;
 import com.intellij.codeInspection.bytecodeAnalysis.asm.AnalyzerExt;
 import com.intellij.codeInspection.bytecodeAnalysis.asm.InterpreterExt;
 import com.intellij.codeInspection.bytecodeAnalysis.asm.LiteAnalyzerExt;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.org.objectweb.asm.Opcodes;
 import org.jetbrains.org.objectweb.asm.Type;
 import org.jetbrains.org.objectweb.asm.tree.*;
@@ -165,6 +166,7 @@ class NullableMethodAnalysis {
     return FinalBot;
   }
 
+  @NotNull
   private static int[] mapOrigins(boolean[] origins) {
     int[] originsMapping = new int[origins.length];
     int mapped = 0;

java/java-analysis-impl/src/com/intellij/codeInspection/bytecodeAnalysis/ProjectBytecodeAnalysis.java

@@ -151,6 +151,7 @@ public class ProjectBytecodeAnalysis {
    * @param methodAnnotations inferred annotations
    * @return Psi annotations
    */
+  @NotNull
   private PsiAnnotation[] toPsi(HKey primaryKey, MethodAnnotations methodAnnotations) {
     boolean notNull = methodAnnotations.notNulls.contains(primaryKey);
     boolean nullable = methodAnnotations.nullables.contains(primaryKey);
@@ -201,6 +202,7 @@ public class ProjectBytecodeAnalysis {
    * @param parameterAnnotations inferred parameter annotations
    * @return Psi annotations
    */
+  @NotNull
   private PsiAnnotation[] toPsi(ParameterAnnotations parameterAnnotations) {
     if (parameterAnnotations.notNull) {
       return new PsiAnnotation[]{

java/java-analysis-impl/src/com/intellij/codeInspection/uncheckedWarnings/UncheckedWarningLocalInspectionBase.java

@@ -61,6 +61,7 @@ public class UncheckedWarningLocalInspectionBase extends BaseJavaBatchLocalInspe
     return uncheckedCb;
   }
 
+  @NotNull
   private static LocalQuickFix[] getChangeVariableTypeFixes(@NotNull PsiVariable parameter, @Nullable PsiType itemType, LocalQuickFix[] generifyFixes) {
     if (itemType instanceof PsiMethodReferenceType) return generifyFixes;
     LOG.assertTrue(parameter.isValid());
@@ -148,8 +149,9 @@ public class UncheckedWarningLocalInspectionBase extends BaseJavaBatchLocalInspe
     };
   }
 
+  @NotNull
   protected LocalQuickFix[] createFixes() {
-    return null;
+    return LocalQuickFix.EMPTY_ARRAY;
   }
 
   private static String isMethodCalledOnRawType(PsiElement expression) {

java/java-analysis-impl/src/com/intellij/codeInspection/visibility/VisibilityInspection.java

@@ -223,7 +223,8 @@ public class VisibilityInspection extends GlobalJavaBatchInspectionTool {
     return null;
   }
 
-  private static CommonProblemDescriptor[] createDescriptions(RefElement refElement, String access, 
+  @NotNull
+  private static CommonProblemDescriptor[] createDescriptions(RefElement refElement, String access,
                                                               @NotNull InspectionManager manager,
                                                               @NotNull GlobalInspectionContext globalContext) {
     final PsiElement element = refElement.getElement();
@@ -250,7 +251,7 @@ public class VisibilityInspection extends GlobalJavaBatchInspectionTool {
                                                                      new AcceptSuggestedAccess(globalContext.getRefManager(), access, quickFixName),
                                                                      ProblemHighlightType.GENERIC_ERROR_OR_WARNING, false)};
     }
-    return null;
+    return CommonProblemDescriptor.EMPTY_ARRAY;
   }
 
   int getMinVisibilityLevel(PsiMember member) {

java/java-analysis-impl/src/com/intellij/refactoring/util/duplicates/DuplicatesFinder.java

@@ -43,14 +43,14 @@ import java.util.*;
 public class DuplicatesFinder {
   private static final Logger LOG = Logger.getInstance("#com.intellij.refactoring.util.duplicates.DuplicatesFinder");
   public static final Key<Pair<PsiVariable, PsiType>> PARAMETER = Key.create("PARAMETER");
-  private final PsiElement[] myPattern;
+  @NotNull private final PsiElement[] myPattern;
   private final InputVariables myParameters;
   private final List<? extends PsiVariable> myOutputParameters;
   private final List<PsiElement> myPatternAsList;
   private boolean myMultipleExitPoints;
   @Nullable private final ReturnValue myReturnValue;
 
-  public DuplicatesFinder(PsiElement[] pattern,
+  public DuplicatesFinder(@NotNull PsiElement[] pattern,
                           InputVariables parameters,
                           @Nullable ReturnValue returnValue,
                           @NotNull List<? extends PsiVariable> outputParameters
@@ -102,6 +102,7 @@ public class DuplicatesFinder {
     return myParameters;
   }
 
+  @NotNull
   public PsiElement[] getPattern() {
     return myPattern;
   }
@@ -674,6 +675,7 @@ public class DuplicatesFinder {
     return false;
   }
 
+  @NotNull
   public static PsiElement[] getFilteredChildren(PsiElement element1) {
     PsiElement[] children1 = element1.getChildren();
     ArrayList<PsiElement> array = new ArrayList<>();

java/java-analysis-impl/src/org/jetbrains/java/generate/config/PolicyOptions.java

@@ -15,6 +15,8 @@
  */
 package org.jetbrains.java.generate.config;
 
+import org.jetbrains.annotations.NotNull;
+
 /**
  * Options for the various policies.
  */
@@ -30,6 +32,7 @@ public class PolicyOptions {
      * Gets the options for the the insert new method policy.
      * @return the options for the the insert new method policy.
      */
+    @NotNull
     public static InsertWhere[] getNewMethodOptions() {
         return newMethodOptions;
     }
@@ -38,6 +41,7 @@ public class PolicyOptions {
      * Gets the options for the the conflict resolution policy.
      * @return the options for the the conflict resolution policy.
      */
+    @NotNull
     public static DuplicationPolicy[] getConflictOptions() {
         return conflictOptions;
     }

java/java-analysis-impl/src/org/jetbrains/java/generate/psi/PsiAdapter.java

@@ -18,7 +18,6 @@ package org.jetbrains.java.generate.psi;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.projectRoots.JavaSdkVersion;
 import com.intellij.openapi.projectRoots.JavaVersionService;
-import com.intellij.openapi.projectRoots.JdkVersionUtil;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.*;
 import com.intellij.psi.codeStyle.CodeStyleManager;
@@ -643,6 +642,7 @@ public class PsiAdapter {
      * @param clazz the class
      * @return the names.
      */
+    @NotNull
     public static String[] getImplementsClassnames(PsiClass clazz) {
         PsiClass[] interfaces = clazz.getInterfaces();
 

java/java-impl/src/com/intellij/codeInsight/CodeInsightUtil.java

@@ -202,6 +202,7 @@ public class CodeInsightUtil {
     };
   }
 
+  @NotNull
   public static PsiExpression[] findExpressionOccurrences(PsiElement scope, PsiExpression expr) {
     List<PsiExpression> array = new ArrayList<>();
     addExpressionOccurrences(RefactoringUtil.unparenthesizeExpression(expr), array, scope);
@@ -231,6 +232,7 @@ public class CodeInsightUtil {
     }
   }
 
+  @NotNull
   public static PsiExpression[] findReferenceExpressions(PsiElement scope, PsiElement referee) {
     ArrayList<PsiElement> array = new ArrayList<>();
     if (scope != null) {

java/java-impl/src/com/intellij/codeInsight/ExpectedTypeUtil.java

@@ -29,6 +29,7 @@ import java.util.*;
 public class ExpectedTypeUtil {
   private static final Logger LOG = Logger.getInstance("#com.intellij.codeInsight.ExpectedTypeUtil");
 
+  @NotNull
   public static ExpectedTypeInfo[] intersect(List<ExpectedTypeInfo[]> typeInfos) {
     if (typeInfos.isEmpty()) return ExpectedTypeInfo.EMPTY_ARRAY;
 
@@ -88,6 +89,7 @@ public class ExpectedTypeUtil {
       return myInfos.iterator();
     }
 
+    @NotNull
     public ExpectedTypeInfo[] toArray() {
       return myInfos.toArray(new ExpectedTypeInfo[myInfos.size()]);
     }

java/java-impl/src/com/intellij/codeInsight/ExpectedTypesProvider.java

@@ -155,6 +155,7 @@ public class ExpectedTypesProvider {
     return visitor.getResult();
   }
 
+  @NotNull
   public static PsiType[] processExpectedTypes(@NotNull ExpectedTypeInfo[] infos,
                                                @NotNull PsiTypeVisitor<PsiType> visitor, @NotNull Project project) {
     LinkedHashSet<PsiType> set = new LinkedHashSet<>();

java/java-impl/src/com/intellij/codeInsight/JavaTargetElementEvaluator.java

@@ -280,6 +280,7 @@ public class JavaTargetElementEvaluator extends TargetElementEvaluatorEx2 implem
     return super.acceptImplementationForReference(reference, element);
   }
 
+  @Nullable
   private static PsiClass[] getClassesWithMember(final PsiReference reference, final PsiMember member) {
     return ApplicationManager.getApplication().runReadAction(new Computable<PsiClass[]>() {
       @Override

java/java-impl/src/com/intellij/codeInsight/completion/JavaCompletionSorting.java

@@ -92,6 +92,7 @@ public class JavaCompletionSorting {
     return result.withRelevanceSorter(sorter);
   }
 
+  @NotNull
   private static ExpectedTypeInfo[] getExpectedTypesWithDfa(CompletionParameters parameters, PsiElement position) {
     if (psiElement().beforeLeaf(psiElement().withText(".")).accepts(position)) {
       return ExpectedTypeInfo.EMPTY_ARRAY;

java/java-impl/src/com/intellij/codeInsight/daemon/impl/JavaLineMarkerProvider.java

@@ -315,6 +315,7 @@ public class JavaLineMarkerProvider extends LineMarkerProviderDescriptor {
     return "Java line markers";
   }
 
+  @NotNull
   @Override
   public Option[] getOptions() {
     return new Option[] {myLambdaOption, myOverriddenOption, myImplementedOption, myOverridingOption, myImplementingOption};

java/java-impl/src/com/intellij/codeInsight/daemon/impl/quickfix/AddExceptionToThrowsFix.java

@@ -111,6 +111,7 @@ public class AddExceptionToThrowsFix extends BaseIntentionAction {
     });
   }
 
+  @NotNull
   private static PsiMethod[] getSuperMethods(@NotNull PsiMethod targetMethod) {
     List<PsiMethod> result = new ArrayList<>();
     collectSuperMethods(targetMethod, result);

java/java-impl/src/com/intellij/codeInsight/daemon/impl/quickfix/AddReturnFix.java

@@ -125,6 +125,7 @@ public class AddReturnFix implements IntentionAction {
     return null;
   }
 
+  @NotNull
   private static PsiVariable[] getDeclaredVariables(PsiMethod method) {
     List<PsiVariable> variables = new ArrayList<>();
     PsiStatement[] statements = method.getBody().getStatements();

java/java-impl/src/com/intellij/codeInsight/daemon/impl/quickfix/ChangeMethodSignatureFromUsageFix.java

@@ -255,6 +255,7 @@ public class ChangeMethodSignatureFromUsageFix implements IntentionAction/*, Hig
     return null;
   }
 
+  @Nullable
   protected ParameterInfoImpl[] getNewParametersInfo(PsiExpression[] expressions,
                                                      PsiMethod targetMethod,
                                                      PsiSubstitutor substitutor) {
@@ -263,6 +264,7 @@ public class ChangeMethodSignatureFromUsageFix implements IntentionAction/*, Hig
                                 new HashSet<>());
   }
 
+  @Nullable
   private ParameterInfoImpl[] getNewParametersInfo(PsiExpression[] expressions,
                                                    PsiMethod targetMethod,
                                                    PsiSubstitutor substitutor,

java/java-impl/src/com/intellij/codeInsight/daemon/impl/quickfix/CreateFromUsageUtils.java

@@ -509,6 +509,7 @@ public class CreateFromUsageUtils {
     return result.toArray(new PsiReferenceExpression[result.size()]);
   }
 
+  @NotNull
   static PsiVariable[] guessMatchingVariables(final PsiExpression expression) {
     List<ExpectedTypeInfo[]> typesList = new ArrayList<>();
     List<String> expectedMethodNames = new ArrayList<>();
@@ -616,6 +617,7 @@ public class CreateFromUsageUtils {
     return compareMembers(c1, c2, expression);
   }
 
+  @NotNull
   private static ExpectedTypeInfo[] equalsExpectedTypes(PsiMethodCallExpression methodCall) {
     final PsiType[] argumentTypes = methodCall.getArgumentList().getExpressionTypes();
     if (argumentTypes.length != 1) {

java/java-impl/src/com/intellij/codeInsight/daemon/impl/quickfix/InitializeFinalFieldInConstructorFix.java

@@ -169,6 +169,7 @@ public class InitializeFinalFieldInConstructorFix implements IntentionAction {
     return Collections.emptyList();
   }
 
+  @NotNull
   private static PsiMethodMember[] toPsiMethodMemberArray(@NotNull PsiMethod[] methods) {
     final PsiMethodMember[] result = new PsiMethodMember[methods.length];
     for (int i = 0; i < methods.length; i++) {
@@ -177,6 +178,7 @@ public class InitializeFinalFieldInConstructorFix implements IntentionAction {
     return result;
   }
 
+  @NotNull
   private static PsiMethod[] toPsiMethodArray(@NotNull List<PsiMethodMember> methodMembers) {
     final PsiMethod[] result = new PsiMethod[methodMembers.size()];
     int i = 0;
@@ -191,6 +193,7 @@ public class InitializeFinalFieldInConstructorFix implements IntentionAction {
     ApplicationManager.getApplication().runWriteAction(() -> defaultConstructorFix.invoke(project, editor, file));
   }
 
+  @NotNull
   private static PsiMethod[] filterIfFieldAlreadyAssigned(@NotNull PsiField field, @NotNull PsiMethod[] ctors) {
     final List<PsiMethod> result = new ArrayList<>(Arrays.asList(ctors));
     for (PsiReference reference : ReferencesSearch.search(field, new LocalSearchScope(ctors))) {

java/java-impl/src/com/intellij/codeInsight/daemon/impl/quickfix/MethodParameterFix.java

@@ -120,6 +120,7 @@ public class MethodParameterFix extends LocalQuickFixAndIntentionActionOnPsiElem
     return false;
   }
 
+  @NotNull
   private ParameterInfoImpl[] getNewParametersInfo(PsiMethod method) throws IncorrectOperationException {
     List<ParameterInfoImpl> result = new ArrayList<>();
     PsiParameter[] parameters = method.getParameterList().getParameters();

java/java-impl/src/com/intellij/codeInsight/daemon/impl/quickfix/RemoveUnusedParameterFix.java

@@ -88,6 +88,7 @@ public class RemoveUnusedParameterFix extends LocalQuickFixAndIntentionActionOnP
     processor.run();
   }
 
+  @NotNull
   public static ParameterInfoImpl[] getNewParametersInfo(PsiMethod method, PsiParameter parameterToRemove) {
     List<ParameterInfoImpl> result = new ArrayList<>();
     PsiParameter[] parameters = method.getParameterList().getParameters();

java/java-impl/src/com/intellij/codeInsight/daemon/impl/quickfix/RenameWrongRefFix.java

@@ -88,6 +88,7 @@ public class RenameWrongRefFix implements IntentionAction {
     return !CreateFromUsageUtils.isValidReference(myRefExpr, myUnresolvedOnly);
   }
 
+  @NotNull
   private LookupElement[] collectItems() {
     Set<LookupElement> items = new LinkedHashSet<>();
     boolean qualified = myRefExpr.getQualifierExpression() != null;

java/java-impl/src/com/intellij/codeInsight/editorActions/CopyPasteReferenceProcessor.java

@@ -136,6 +136,7 @@ public abstract class CopyPasteReferenceProcessor<TRef extends PsiElement> exten
             qClassName, staticMemberName));
   }
 
+  @NotNull
   protected abstract TRef[] findReferencesToRestore(PsiFile file,
                                                                            RangeMarker bounds,
                                                                            ReferenceData[] referenceData);
@@ -154,7 +155,7 @@ public abstract class CopyPasteReferenceProcessor<TRef extends PsiElement> exten
   protected abstract void restoreReferences(ReferenceData[] referenceData,
                                             TRef[] refs);
 
-  private static void askReferencesToRestore(Project project, PsiElement[] refs,
+  private static void askReferencesToRestore(Project project, @NotNull PsiElement[] refs,
                                       ReferenceData[] referenceData) {
     PsiManager manager = PsiManager.getInstance(project);
 

java/java-impl/src/com/intellij/codeInsight/editorActions/JavaCopyPasteReferenceProcessor.java

@@ -22,6 +22,7 @@ import com.intellij.openapi.editor.RangeMarker;
 import com.intellij.openapi.util.TextRange;
 import com.intellij.psi.*;
 import com.intellij.util.IncorrectOperationException;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
@@ -59,6 +60,7 @@ public class JavaCopyPasteReferenceProcessor extends CopyPasteReferenceProcessor
   }
 
 
+  @NotNull
   @Override
   protected PsiJavaCodeReferenceElement[] findReferencesToRestore(PsiFile file,
                                                                        RangeMarker bounds,

java/java-impl/src/com/intellij/codeInsight/editorActions/ReferenceTransferableData.java

@@ -15,6 +15,8 @@
  */
 package com.intellij.codeInsight.editorActions;
 
+import org.jetbrains.annotations.NotNull;
+
 import java.awt.datatransfer.DataFlavor;
 import java.io.Serializable;
 
@@ -24,7 +26,7 @@ import java.io.Serializable;
 public class ReferenceTransferableData implements TextBlockTransferableData, Cloneable, Serializable {
   private final ReferenceData[] myReferenceDatas;
 
-  public ReferenceTransferableData(final ReferenceData[] referenceDatas) {
+  public ReferenceTransferableData(@NotNull ReferenceData[] referenceDatas) {
     myReferenceDatas = referenceDatas;
   }
 
@@ -65,6 +67,7 @@ public class ReferenceTransferableData implements TextBlockTransferableData, Clo
     return new ReferenceTransferableData(newReferenceData);
   }
 
+  @NotNull
   public ReferenceData[] getData() {
     return myReferenceDatas;
   }

java/java-impl/src/com/intellij/codeInsight/editorActions/RestoreReferencesDialog.java

@@ -27,6 +27,7 @@ import com.intellij.ui.components.JBLabel;
 import com.intellij.ui.components.JBList;
 import com.intellij.util.ui.JBUI;
 import com.intellij.util.ui.UIUtil;
+import org.jetbrains.annotations.NotNull;
 
 import javax.swing.*;
 import java.awt.*;
@@ -97,6 +98,7 @@ class RestoreReferencesDialog extends DialogWrapper {
     return "#com.intellij.codeInsight.editorActions.RestoreReferencesDialog";
   }
 
+  @NotNull
   public Object[] getSelectedElements(){
     return mySelectedElements;
   }

java/java-impl/src/com/intellij/codeInsight/highlighting/JavaBraceMatcher.java

@@ -35,6 +35,7 @@ public class JavaBraceMatcher implements PairedBraceMatcher {
       new BracePair(JavaTokenType.LT, JavaTokenType.GT, false)
   };
 
+  @NotNull
   @Override
   public BracePair[] getPairs() {
     return pairs;

java/java-impl/src/com/intellij/codeInspection/deadCode/UnusedDeclarationInspectionMerger.java

@@ -19,6 +19,7 @@ import com.intellij.codeInspection.ex.InspectionElementsMergerBase;
 import com.intellij.codeInspection.unusedSymbol.UnusedSymbolLocalInspection;
 import com.intellij.openapi.util.WriteExternalException;
 import org.jdom.Element;
+import org.jetbrains.annotations.NotNull;
 
 public class UnusedDeclarationInspectionMerger extends InspectionElementsMergerBase {
   private static final String UNUSED_SYMBOL = "UNUSED_SYMBOL";
@@ -29,6 +30,7 @@ public class UnusedDeclarationInspectionMerger extends InspectionElementsMergerB
     return UnusedDeclarationInspectionBase.SHORT_NAME;
   }
 
+  @NotNull
   @Override
   public String[] getSourceToolNames() {
     return new String[] {UNUSED_SYMBOL, UNUSED_DECLARATION};

java/java-impl/src/com/intellij/codeInspection/inferNullity/InferNullityAnnotationsAction.java

@@ -59,6 +59,7 @@ import com.intellij.ui.TitledSeparator;
 import com.intellij.usageView.UsageInfo;
 import com.intellij.usageView.UsageViewUtil;
 import com.intellij.usages.*;
+import com.intellij.util.ObjectUtils;
 import com.intellij.util.Processor;
 import com.intellij.util.SequentialModalProgressTask;
 import com.intellij.util.containers.ContainerUtil;
@@ -299,9 +300,10 @@ public class InferNullityAnnotationsAction extends BaseAnalysisAction {
   @NotNull
   private Factory<UsageSearcher> rerunFactory(@NotNull final Project project, @NotNull final AnalysisScope scope) {
     return () -> new UsageInfoSearcherAdapter() {
+      @NotNull
       @Override
       protected UsageInfo[] findUsages() {
-        return InferNullityAnnotationsAction.this.findUsages(project, scope, scope.getFileCount());
+        return ObjectUtils.notNull(InferNullityAnnotationsAction.this.findUsages(project, scope, scope.getFileCount()), UsageInfo.EMPTY_ARRAY);
       }
 
       @Override

java/java-impl/src/com/intellij/codeInspection/java18api/Java8MapApiInspectionMerger.java

@@ -16,6 +16,7 @@
 package com.intellij.codeInspection.java18api;
 
 import com.intellij.codeInspection.ex.InspectionElementsMerger;
+import org.jetbrains.annotations.NotNull;
 
 public class Java8MapApiInspectionMerger extends InspectionElementsMerger {
   private static final String COLLECTION_API_INSPECTION = "Java8CollectionsApi";
@@ -26,6 +27,7 @@ public class Java8MapApiInspectionMerger extends InspectionElementsMerger {
     return Java8MapApiInspection.SHORT_NAME;
   }
 
+  @NotNull
   @Override
   public String[] getSourceToolNames() {
     return new String[] {COLLECTION_API_INSPECTION, REPLACE_MAP_GET_INSPECTION};

java/java-impl/src/com/intellij/codeInspection/uncheckedWarnings/UncheckedWarningLocalInspection.java

@@ -20,6 +20,7 @@ import com.intellij.codeInsight.daemon.impl.quickfix.GenerifyFileFix;
 import com.intellij.codeInspection.LocalQuickFix;
 import com.intellij.openapi.util.Pass;
 import com.intellij.util.ui.JBUI;
+import org.jetbrains.annotations.NotNull;
 
 import javax.swing.*;
 import java.awt.*;
@@ -30,6 +31,7 @@ import java.awt.*;
  */
 public class UncheckedWarningLocalInspection extends UncheckedWarningLocalInspectionBase {
 
+  @NotNull
   @Override
   protected LocalQuickFix[] createFixes() {
     return new LocalQuickFix[]{new GenerifyFileFix()};

java/java-impl/src/com/intellij/ide/util/PackageUtil.java

@@ -282,7 +282,8 @@ public class PackageUtil {
     return psiDirectory;
   }
 
-  private static PsiDirectory[] filterSourceDirectories(PsiDirectory baseDir, Project project, PsiDirectory[] moduleDirectories) {
+  @NotNull
+  private static PsiDirectory[] filterSourceDirectories(PsiDirectory baseDir, Project project, @NotNull PsiDirectory[] moduleDirectories) {
     final ProjectFileIndex fileIndex = ProjectRootManager.getInstance(project).getFileIndex();
     if (fileIndex.isInTestSourceContent(baseDir.getVirtualFile())) {
       List<PsiDirectory> result = new ArrayList<>();
@@ -296,6 +297,7 @@ public class PackageUtil {
     return moduleDirectories;
   }
 
+  @NotNull
   private static PsiDirectory[] getPackageDirectoriesInModule(PsiPackage rootPackage, Module module) {
     return rootPackage.getDirectories(GlobalSearchScope.moduleScope(module));
   }

java/java-impl/src/com/intellij/openapi/roots/impl/ModulePackageIndexImpl.java

@@ -40,11 +40,13 @@ public class ModulePackageIndexImpl extends ModulePackageIndex {
     }
   };
 
+  @NotNull
   @Override
   public Query<VirtualFile> getDirsByPackageName(@NotNull String packageName, boolean includeLibrarySources) {
     return new FilteredQuery<>(myDirectoryIndex.getDirectoriesByPackageName(packageName, includeLibrarySources), myDirCondition);
   }
 
+  @NotNull
   @Override
   public VirtualFile[] getDirectoriesByPackageName(@NotNull String packageName, boolean includeLibrarySources) {
     return getDirsByPackageName(packageName, includeLibrarySources).toArray(VirtualFile.EMPTY_ARRAY);

java/java-impl/src/com/intellij/psi/AbstractQualifiedReference.java

@@ -64,6 +64,7 @@ public abstract class AbstractQualifiedReference<T extends AbstractQualifiedRefe
     return this;
   }
 
+  @NotNull
   protected abstract ResolveResult[] resolveInner();
 
   @Override

java/java-impl/src/com/intellij/psi/filters/getters/ExpectedTypesGetter.java

@@ -22,6 +22,7 @@ import com.intellij.psi.PsiExpression;
 import com.intellij.psi.PsiType;
 import com.intellij.psi.util.PsiTreeUtil;
 import gnu.trove.THashSet;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.Set;
 
@@ -34,6 +35,7 @@ import java.util.Set;
  */
 public class ExpectedTypesGetter {
 
+  @NotNull
   public static PsiType[] getExpectedTypes(final PsiElement context, boolean defaultTypes) {
     PsiExpression expression = PsiTreeUtil.getContextOfType(context, PsiExpression.class, true);
     if(expression == null) return PsiType.EMPTY_ARRAY;
@@ -41,6 +43,7 @@ public class ExpectedTypesGetter {
     return extractTypes(ExpectedTypesProvider.getExpectedTypes(expression, true), defaultTypes);
   }
 
+  @NotNull
   public static PsiType[] extractTypes(ExpectedTypeInfo[] infos, boolean defaultTypes) {
     Set<PsiType> result = new THashSet<>(infos.length);
     for (ExpectedTypeInfo info : infos) {

java/java-impl/src/com/intellij/psi/filters/getters/InstanceOfLeftPartTypeGetter.java

@@ -18,6 +18,7 @@ package com.intellij.psi.filters.getters;
 import com.intellij.psi.*;
 import com.intellij.psi.filters.FilterUtil;
 import com.intellij.psi.util.PsiTreeUtil;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Created by IntelliJ IDEA.
@@ -27,6 +28,7 @@ import com.intellij.psi.util.PsiTreeUtil;
  * To change this template use Options | File Templates.
  */
 public class InstanceOfLeftPartTypeGetter {
+  @NotNull
   public static PsiType[] getLeftTypes(PsiElement context) {
     if((context = FilterUtil.getPreviousElement(context, true)) == null) return PsiType.EMPTY_ARRAY;
     if(!PsiKeyword.INSTANCEOF.equals(context.getText())) return PsiType.EMPTY_ARRAY;

java/java-impl/src/com/intellij/psi/impl/beanProperties/BeanPropertyElement.java

@@ -89,6 +89,7 @@ public class BeanPropertyElement extends FakePsiElement implements PsiMetaOwner,
 
   }
 
+  @NotNull
   @Override
   public Object[] getDependences() {
     return ArrayUtil.EMPTY_OBJECT_ARRAY;

java/java-impl/src/com/intellij/psi/impl/cache/SmartIntToIntArrayMap.java

@@ -19,6 +19,7 @@ import com.intellij.util.ArrayUtil;
 import gnu.trove.TIntArrayList;
 import gnu.trove.TIntIntHashMap;
 import gnu.trove.TIntObjectHashMap;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 /**
@@ -28,6 +29,7 @@ public class SmartIntToIntArrayMap {
   @Nullable TIntObjectHashMap<TIntArrayList> myMultipleValuesMap;
   TIntIntHashMap mySingleValueMap = new TIntIntHashMap(10, 0.9f);
 
+  @NotNull
   public int[] keys() {
     int[] multiKeys = myMultipleValuesMap != null ? myMultipleValuesMap.keys() : ArrayUtil.EMPTY_INT_ARRAY;
     int[] singleKeys = mySingleValueMap.keys();
@@ -95,6 +97,7 @@ public class SmartIntToIntArrayMap {
     }
   }
 
+  @NotNull
   public int[] get(int key) {
     if (mySingleValueMap.containsKey(key)) {
       int id = mySingleValueMap.get(key);
@@ -104,6 +107,7 @@ public class SmartIntToIntArrayMap {
     return getFromMultimap(key);
   }
 
+  @NotNull
   private int[] getFromMultimap(int key) {
     TIntArrayList res = myMultipleValuesMap != null ? myMultipleValuesMap.get(key) : null;
     if (res == null) return ArrayUtil.EMPTY_INT_ARRAY;

java/java-impl/src/com/intellij/psi/impl/migration/MigrationClassImpl.java

@@ -127,6 +127,7 @@ public class MigrationClassImpl extends LightElement implements PsiClass{
       .findClass(CommonClassNames.JAVA_LANG_OBJECT, GlobalSearchScope.allScope(myManager.getProject()));
   }
 
+  @NotNull
   @Override
   public PsiClass[] getInterfaces() {
     return PsiClass.EMPTY_ARRAY;

java/java-impl/src/com/intellij/psi/impl/migration/MigrationPackageImpl.java

@@ -50,6 +50,7 @@ public class MigrationPackageImpl extends PsiPackageImpl implements PsiPackage {
     throw new UnsupportedOperationException();
   }
 
+  @NotNull
   @Override
   public VirtualFile[] occursInPackagePrefixes() {
     return VirtualFile.EMPTY_ARRAY;

java/java-impl/src/com/intellij/psi/impl/source/resolve/reference/impl/providers/JavaClassReference.java

@@ -30,7 +30,6 @@ import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.module.Module;
 import com.intellij.openapi.module.ModuleUtilCore;
 import com.intellij.openapi.project.Project;
-import com.intellij.openapi.util.Condition;
 import com.intellij.openapi.util.Iconable;
 import com.intellij.openapi.util.Key;
 import com.intellij.openapi.util.TextRange;
@@ -268,6 +267,7 @@ public class JavaClassReference extends GenericReference implements PsiJavaRefer
     return context == null ? JavaPsiFacade.getInstance(getElement().getProject()).findPackage("") : context;
   }
 
+  @Nullable
   public String[] getExtendClassNames() {
     return JavaClassReferenceProvider.EXTEND_CLASS_NAMES.getValue(getOptions());
   }

java/java-impl/src/com/intellij/psi/impl/source/resolve/reference/impl/providers/JavaClassReferenceProvider.java

@@ -115,6 +115,7 @@ public class JavaClassReferenceProvider extends GenericReferenceProvider impleme
     return getReferencesByElement(element);
   }
 
+  @NotNull
   public PsiReference[] getReferencesByElement(@NotNull PsiElement element) {
     final int offsetInElement = ElementManipulators.getOffsetInElement(element);
     final String text = ElementManipulators.getValueText(element);

java/java-impl/src/com/intellij/psi/impl/source/resolve/reference/impl/providers/PathListReferenceProvider.java

@@ -39,6 +39,7 @@ public class PathListReferenceProvider extends PsiReferenceProvider {
     return true;
   }
 
+  @NotNull
   public PsiReference[] getReferencesByElement(@NotNull PsiElement element) {
 
     PsiReference[] result = PsiReference.EMPTY_ARRAY;
@@ -75,6 +76,7 @@ public class PathListReferenceProvider extends PsiReferenceProvider {
     return ',';
   }
 
+  @NotNull
   protected PsiReference[] createReferences(@NotNull PsiElement element, String s, int offset, final boolean soft) {
     int contentOffset = StringUtil.findFirst(s, CharFilter.NOT_WHITESPACE_FILTER);
     if (contentOffset >= 0) {

java/java-indexing-api/src/com/intellij/psi/search/searches/AnnotatedElementsSearch.java

@@ -54,6 +54,7 @@ public class AnnotatedElementsSearch extends ExtensibleQueryFactory<PsiModifierL
       return myScope;
     }
 
+    @NotNull
     public Class<? extends PsiModifierListOwner>[] getTypes() {
       return myTypes;
     }

java/java-indexing-impl/src/com/intellij/openapi/roots/impl/ProjectPackageIndexImpl.java

@@ -27,11 +27,13 @@ public class ProjectPackageIndexImpl extends PackageIndex {
     myDirectoryIndex = directoryIndex;
   }
 
+  @NotNull
   @Override
   public VirtualFile[] getDirectoriesByPackageName(@NotNull String packageName, boolean includeLibrarySources) {
     return getDirsByPackageName(packageName, includeLibrarySources).toArray(VirtualFile.EMPTY_ARRAY);
   }
 
+  @NotNull
   @Override
   public Query<VirtualFile> getDirsByPackageName(@NotNull String packageName, boolean includeLibrarySources) {
     return myDirectoryIndex.getDirectoriesByPackageName(packageName, includeLibrarySources);

java/java-psi-api/src/com/intellij/openapi/roots/PackageIndex.java

@@ -37,6 +37,7 @@ public abstract class PackageIndex {
    * @param includeLibrarySources if true, directories under library sources are included in the returned list.
    * @return the list of directories.
    */
+  @NotNull
   public abstract VirtualFile[] getDirectoriesByPackageName(@NotNull String packageName, boolean includeLibrarySources);
 
   /**
@@ -47,5 +48,6 @@ public abstract class PackageIndex {
    * @param includeLibrarySources if true, directories under library sources are included in the returned list.
    * @return the query returning the list of directories.
    */
+  @NotNull
   public abstract Query<VirtualFile> getDirsByPackageName(@NotNull String packageName, boolean includeLibrarySources);
 }

java/java-psi-api/src/com/intellij/psi/HierarchicalMethodSignature.java

@@ -33,6 +33,7 @@ public abstract class HierarchicalMethodSignature extends MethodSignatureBackedB
           getParameterTypes(signature.getMethod()), signature.getTypeParameters());
   }
 
+  @NotNull
   private static PsiType[] getParameterTypes(PsiMethod method) {
     final PsiParameter[] parameters = method.getParameterList().getParameters();
     final PsiType[] paramTypes = PsiType.createArray(parameters.length);

java/java-psi-api/src/com/intellij/psi/LambdaUtil.java

@@ -554,6 +554,7 @@ public class LambdaUtil {
            typeByExpression instanceof PsiLambdaParameterType;
   }
 
+  @NotNull
   public static PsiReturnStatement[] getReturnStatements(PsiLambdaExpression lambdaExpression) {
     final PsiElement body = lambdaExpression.getBody();
     return body instanceof PsiCodeBlock ? PsiUtil.findReturnStatements((PsiCodeBlock)body) : PsiReturnStatement.EMPTY_ARRAY;

java/java-psi-api/src/com/intellij/psi/PsiClass.java

@@ -116,6 +116,7 @@ public interface PsiClass
    *
    * @return the list of interfaces.
    */
+  @NotNull
   PsiClass[] getInterfaces();
 
   /**
@@ -124,7 +125,8 @@ public interface PsiClass
    * @return the list of classes or interfaces. May return zero elements when jdk is
    *         not configured, so no java.lang.Object is found
    */
-  @NotNull PsiClass[] getSupers();
+  @NotNull
+  PsiClass[] getSupers();
 
   /**
    * Returns the list of class types for the classes and interfaces extended or

java/java-psi-api/src/com/intellij/psi/PsiIntersectionType.java

@@ -15,12 +15,10 @@
  */
 package com.intellij.psi;
 
-import com.intellij.openapi.util.Computable;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.search.GlobalSearchScope;
 import com.intellij.psi.util.PsiUtil;
 import com.intellij.psi.util.TypeConversionUtil;
-import com.intellij.util.Function;
 import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NotNull;
 
@@ -50,7 +48,7 @@ public class PsiIntersectionType extends PsiType.Stub {
   }
 
   @NotNull
-  public static PsiType createIntersection(boolean flatten, PsiType... conjuncts) {
+  public static PsiType createIntersection(boolean flatten, @NotNull PsiType... conjuncts) {
     assert conjuncts.length > 0;
     if (flatten) {
       conjuncts = flattenAndRemoveDuplicates(conjuncts);
@@ -59,7 +57,8 @@ public class PsiIntersectionType extends PsiType.Stub {
     return new PsiIntersectionType(conjuncts);
   }
 
-  private static PsiType[] flattenAndRemoveDuplicates(final PsiType[] conjuncts) {
+  @NotNull
+  private static PsiType[] flattenAndRemoveDuplicates(@NotNull PsiType[] conjuncts) {
     try {
       final Set<PsiType> flattenConjuncts = PsiCapturedWildcardType.guard.doPreventingRecursion(conjuncts, true, () -> flatten(conjuncts, ContainerUtil.<PsiType>newLinkedHashSet()));
       if (flattenConjuncts == null) {

java/java-psi-api/src/com/intellij/psi/PsiPackage.java

@@ -90,6 +90,7 @@ public interface PsiPackage extends PsiCheckedRenameElement, NavigationItem, Psi
    *
    * @since 14.1
    */
+  @NotNull
   PsiFile[] getFiles(@NotNull GlobalSearchScope scope);
 
   /**
@@ -114,6 +115,7 @@ public interface PsiPackage extends PsiCheckedRenameElement, NavigationItem, Psi
    *
    * @return the array of virtual files for the source roots.
    */
+  @NotNull
   VirtualFile[] occursInPackagePrefixes();
 
   @Override

java/java-psi-api/src/com/intellij/psi/PsiTypeParameterList.java

@@ -15,6 +15,8 @@
  */
 package com.intellij.psi;
 
+import org.jetbrains.annotations.NotNull;
+
 /**
  * Represents a list of generic type parameters for a class or method.
  *
@@ -26,6 +28,7 @@ public interface PsiTypeParameterList extends PsiElement {
    *
    * @return the array of type parameters.
    */
+  @NotNull
   PsiTypeParameter[] getTypeParameters();
 
   /**

java/java-psi-api/src/com/intellij/psi/infos/MethodCandidateInfo.java

@@ -436,6 +436,7 @@ public class MethodCandidateInfo extends CandidateInfo{
     }
   }
 
+  @Nullable
   public PsiType[] getArgumentTypes() {
     return myArgumentTypes;
   }

java/java-psi-api/src/com/intellij/psi/javadoc/PsiDocTag.java

@@ -47,6 +47,7 @@ public interface PsiDocTag extends PsiElement, PsiNamedElement {
   /**
    * Returns the list of all elements representing the contents of a tag.
    */
+  @NotNull
   PsiElement[] getDataElements();
 
   /**

java/java-psi-api/src/com/intellij/psi/util/PsiTypesUtil.java

@@ -334,8 +334,9 @@ public class PsiTypesUtil {
     return parameterType;
   }
 
+  @NotNull
   public static PsiTypeParameter[] filterUnusedTypeParameters(final PsiType superReturnTypeInBaseClassType,
-                                                              final PsiTypeParameter[] typeParameters) {
+                                                              @NotNull PsiTypeParameter[] typeParameters) {
     if (typeParameters.length == 0) return typeParameters;
 
     final Set<PsiTypeParameter> usedParameters = new HashSet<>();

java/java-psi-impl/src/com/intellij/core/CorePackageIndex.java

@@ -49,11 +49,13 @@ public class CorePackageIndex extends PackageIndex {
     return result;
   }
 
+  @NotNull
   @Override
   public VirtualFile[] getDirectoriesByPackageName(@NotNull String packageName, boolean includeLibrarySources) {
     return getDirsByPackageName(packageName, includeLibrarySources).toArray(VirtualFile.EMPTY_ARRAY);
   }
 
+  @NotNull
   @Override
   public Query<VirtualFile> getDirsByPackageName(@NotNull String packageName, boolean includeLibrarySources) {
     return new CollectionQuery<>(findDirectoriesByPackageName(packageName));

java/java-psi-impl/src/com/intellij/psi/PsiDiamondTypeImpl.java

@@ -409,6 +409,7 @@ public class PsiDiamondTypeImpl extends PsiDiamondType {
     }
   }
 
+  @NotNull
   private static PsiTypeParameter[] getAllTypeParams(PsiTypeParameterListOwner listOwner, PsiClass containingClass) {
     Set<PsiTypeParameter> params = new LinkedHashSet<>();
     Collections.addAll(params, containingClass.getTypeParameters());

java/java-psi-impl/src/com/intellij/psi/controlFlow/CompositeInstructionClientVisitor.java

@@ -16,6 +16,8 @@
 
 package com.intellij.psi.controlFlow;
 
+import org.jetbrains.annotations.NotNull;
+
 class CompositeInstructionClientVisitor extends InstructionClientVisitor<Object[]> {
   private final InstructionClientVisitor[] myVisitors;
 
@@ -24,6 +26,7 @@ class CompositeInstructionClientVisitor extends InstructionClientVisitor<Object[
   }
 
   @Override
+  @NotNull
   public Object[] getResult() {
     Object[] result = new Object[myVisitors.length];
     for (int i = 0; i < myVisitors.length; i++) {

java/java-psi-impl/src/com/intellij/psi/controlFlow/ControlFlowUtil.java

@@ -343,6 +343,7 @@ public class ControlFlowUtil {
     return array;
   }
 
+  @NotNull
   public static PsiVariable[] getOutputVariables(ControlFlow flow, int start, int end, int[] exitPoints) {
     Collection<PsiVariable> writtenVariables = getWrittenVariables(flow, start, end, false);
     ArrayList<PsiVariable> array = new ArrayList<>();
@@ -1008,6 +1009,7 @@ public class ControlFlowUtil {
     return visitor.getResult().booleanValue();
   }
 
+  @NotNull
   public static Object[] getAllWorldProblemsAtOnce(final ControlFlow flow) {
     InstructionClientVisitor[] visitors = {
       new ReturnPresentClientVisitor(flow),
@@ -2044,6 +2046,7 @@ public class ControlFlowUtil {
       }
     }
 
+    @NotNull
     int[] getNextOffsets(int offset) {
       return nextOffsets[offset] != null ? nextOffsets[offset] : ArrayUtil.EMPTY_INT_ARRAY;
     }

java/java-psi-impl/src/com/intellij/psi/controlFlow/DefUseUtil.java

@@ -454,6 +454,7 @@ public class DefUseUtil {
   }
 
 
+  @NotNull
   private static IntArrayList[] getBackwardTraces(final List<Instruction> instructions) {
     final IntArrayList[] states = new IntArrayList[instructions.size()];
     for (int i = 0; i < states.length; i++) {

java/java-psi-impl/src/com/intellij/psi/controlFlow/ReturnInstruction.java

@@ -49,6 +49,7 @@ public class ReturnInstruction extends GoToInstruction {
     }
   }
 
+  @NotNull
   public int[] getPossibleReturnOffsets() {
     return offset == 0 ?
         new int[]{

java/java-psi-impl/src/com/intellij/psi/impl/PsiImplUtil.java

@@ -331,6 +331,7 @@ public class PsiImplUtil {
   }
 
   /** @deprecated use {@link AnnotationTargetUtil#getTargetsForLocation(PsiAnnotationOwner)} (to be removed ion IDEA 17) */
+  @NotNull
   public static PsiAnnotation.TargetType[] getTargetsForLocation(@Nullable PsiAnnotationOwner owner) {
     return AnnotationTargetUtil.getTargetsForLocation(owner);
   }
@@ -560,6 +561,7 @@ public class PsiImplUtil {
     return null;
   }
 
+  @NotNull
   public static PsiStatement[] getChildStatements(@NotNull CompositeElement psiCodeBlock) {
     ApplicationManager.getApplication().assertReadAccessAllowed();
     // no lock is needed because all chameleons are expanded already
@@ -713,6 +715,7 @@ public class PsiImplUtil {
     return multiResolveImpl(manager.getProject(), psiFile, element, incompleteCode, resolver);
   }
 
+  @NotNull
   public static <T extends PsiJavaCodeReferenceElement> JavaResolveResult[] multiResolveImpl(@NotNull Project project,
                                                                                              @NotNull PsiFile psiFile,
                                                                                              @NotNull T element,

java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsClassImpl.java

@@ -126,6 +126,7 @@ public class ClsClassImpl extends ClsMemberImpl<PsiClassStub<?>> implements PsiE
     return PsiClassImplUtil.getSuperClass(this);
   }
 
+  @NotNull
   @Override
   public PsiClass[] getInterfaces() {
     return PsiClassImplUtil.getInterfaces(this);

java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsDocTagImpl.java

@@ -100,6 +100,7 @@ class ClsDocTagImpl extends ClsElementImpl implements PsiDocTag {
     return myNameElement;
   }
 
+  @NotNull
   @Override
   public PsiElement[] getDataElements() {
     return PsiElement.EMPTY_ARRAY;

java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsTypeParameterImpl.java

@@ -247,6 +247,7 @@ public class ClsTypeParameterImpl extends ClsRepositoryPsiElement<PsiTypeParamet
     return PsiClassImplUtil.getSuperClass(this);
   }
 
+  @NotNull
   @Override
   public PsiClass[] getInterfaces() {
     return PsiClassImplUtil.getInterfaces(this);

java/java-psi-impl/src/com/intellij/psi/impl/compiled/ClsTypeParametersListImpl.java

@@ -61,6 +61,7 @@ public class ClsTypeParametersListImpl extends ClsRepositoryPsiElement<PsiTypePa
     }
   }
 
+  @NotNull
   @Override
   public PsiTypeParameter[] getTypeParameters() {
     return getStub().getChildrenByType(JavaStubElementTypes.TYPE_PARAMETER, PsiTypeParameter.ARRAY_FACTORY);

java/java-psi-impl/src/com/intellij/psi/impl/file/PsiPackageImpl.java

@@ -101,6 +101,7 @@ public class PsiPackageImpl extends PsiPackageBase implements PsiPackage, Querya
     PsiPackageImplementationHelper.getInstance().handleQualifiedNameChange(this, newQualifiedName);
   }
 
+  @NotNull
   @Override
   public VirtualFile[] occursInPackagePrefixes() {
     return PsiPackageImplementationHelper.getInstance().occursInPackagePrefixes(this);
@@ -162,6 +163,7 @@ public class PsiPackageImpl extends PsiPackageBase implements PsiPackage, Querya
     return getFacade().getClasses(this, scope);
   }
 
+  @NotNull
   @Override
   public PsiFile[] getFiles(@NotNull GlobalSearchScope scope) {
     return getFacade().getPackageFiles(this, scope);
@@ -213,6 +215,7 @@ public class PsiPackageImpl extends PsiPackageBase implements PsiPackage, Querya
     return classes;
   }
 
+  @NotNull
   private PsiClass[] getCachedClassInDumbMode(final String name, GlobalSearchScope scope) {
     Map<GlobalSearchScope, Map<String, PsiClass[]>> scopeMap = SoftReference.dereference(myDumbModeFullCache);
     if (scopeMap == null) {

java/java-psi-impl/src/com/intellij/psi/impl/light/AbstractLightClass.java

@@ -149,6 +149,7 @@ public abstract class AbstractLightClass extends LightElement implements PsiClas
     return getDelegate().getSuperClass();
   }
 
+  @NotNull
   @Override
   public PsiClass[] getInterfaces() {
     return getDelegate().getInterfaces();

java/java-psi-impl/src/com/intellij/psi/impl/light/LightModifierList.java

@@ -135,6 +135,7 @@ public class LightModifierList extends LightElement implements PsiModifierList {
     return buffer.toString();
   }
 
+  @NotNull
   public String[] getModifiers() {
     return ArrayUtil.toStringArray(myModifiers);
   }

java/java-psi-impl/src/com/intellij/psi/impl/light/LightPsiClassBase.java

@@ -106,6 +106,7 @@ public abstract class LightPsiClassBase extends LightElement implements PsiClass
     return PsiClassImplUtil.getSuperClass(this);
   }
 
+  @NotNull
   @Override
   public PsiClass[] getInterfaces() {
     return PsiClassImplUtil.getInterfaces(this);

java/java-psi-impl/src/com/intellij/psi/impl/light/LightTypeParameterListBuilder.java

@@ -48,6 +48,7 @@ public class LightTypeParameterListBuilder extends LightElement implements PsiTy
     }
   }
 
+  @NotNull
   @Override
   public PsiTypeParameter[] getTypeParameters() {
     if (cached == null) {

java/java-psi-impl/src/com/intellij/psi/impl/source/ClassInnerStuffCache.java

@@ -44,6 +44,7 @@ public class ClassInnerStuffCache {
     myClass = aClass;
   }
 
+  @NotNull
   private static <T> T[] copy(T[] value) {
     return value.length == 0 ? value : value.clone();
   }

java/java-psi-impl/src/com/intellij/psi/impl/source/PsiClassImpl.java

@@ -218,6 +218,7 @@ public class PsiClassImpl extends JavaStubPsiElement<PsiClassStub<?>> implements
     return PsiClassImplUtil.getSuperClass(this);
   }
 
+  @NotNull
   @Override
   public PsiClass[] getInterfaces() {
     return PsiClassImplUtil.getInterfaces(this);

java/java-psi-impl/src/com/intellij/psi/impl/source/PsiClassReferenceType.java

@@ -53,6 +53,7 @@ public class PsiClassReferenceType extends PsiClassType.Stub {
     myReference = reference;
   }
 
+  @NotNull
   private static PsiAnnotation[] collectAnnotations(PsiJavaCodeReferenceElement reference) {
     List<PsiAnnotation> result = null;
     for (PsiElement child = reference.getFirstChild(); child != null; child = child.getNextSibling()) {

java/java-psi-impl/src/com/intellij/psi/impl/source/javadoc/PsiDocMethodOrFieldRef.java

@@ -135,12 +135,14 @@ public class PsiDocMethodOrFieldRef extends CompositePsiElement implements PsiDo
     return null;
   }
 
+  @NotNull
   public static PsiVariable[] getAllVariables(PsiElement scope, PsiElement place) {
     final SmartList<PsiVariable> result = new SmartList<>();
     scope.processDeclarations(new FilterScopeProcessor<>(ElementClassFilter.VARIABLE, result), ResolveState.initial(), null, place);
     return result.toArray(new PsiVariable[result.size()]);
   }
 
+  @NotNull
   public static PsiMethod[] getAllMethods(PsiElement scope, PsiElement place) {
     final SmartList<PsiMethod> result = new SmartList<>();
     scope.processDeclarations(new FilterScopeProcessor<>(ElementClassFilter.METHOD, result), ResolveState.initial(), null, place);

java/java-psi-impl/src/com/intellij/psi/impl/source/javadoc/PsiDocTagImpl.java

@@ -57,6 +57,7 @@ public class PsiDocTagImpl extends CompositePsiElement implements PsiDocTag, Con
     return (PsiDocTagValue)findPsiChildByType(TAG_VALUE_BIT_SET);
   }
 
+  @NotNull
   @Override
   public PsiElement[] getDataElements() {
     return getChildrenAsPsiElements(VALUE_BIT_SET, PsiElement.ARRAY_FACTORY);

java/java-psi-impl/src/com/intellij/psi/impl/source/javadoc/PsiInlineDocTagImpl.java

@@ -59,11 +59,13 @@ public class PsiInlineDocTagImpl extends CompositePsiElement implements PsiInlin
     return findPsiChildByType(DOC_TAG_NAME);
   }
 
+  @NotNull
   @Override
   public PsiElement[] getDataElements() {
     return getChildrenAsPsiElements(VALUE_BIT_SET, PsiElement.ARRAY_FACTORY);
   }
 
+  @NotNull
   public PsiElement[] getDataElementsIgnoreWhitespaces() {
     return getChildrenAsPsiElements(VALUE_NO_WHITESPACE_BIT_SET, PsiElement.ARRAY_FACTORY);
   }

java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/StaticImportResolveProcessor.java

@@ -99,6 +99,7 @@ public class StaticImportResolveProcessor extends BaseScopeProcessor implements
     return super.getHint(hintKey);
   }
 
+  @NotNull
   public JavaResolveResult[] getResults() {
     if (myResults.size() + myFieldResults.size() + myClassResult.size() > 1) {
       filterInvalid(myResults);

java/java-psi-impl/src/com/intellij/psi/impl/source/tree/java/PsiTypeParameterImpl.java

@@ -292,6 +292,7 @@ public class PsiTypeParameterImpl extends JavaStubPsiElement<PsiTypeParameterStu
     return PsiClassImplUtil.getSuperClass(this);
   }
 
+  @NotNull
   @Override
   public PsiClass[] getInterfaces() {
     return PsiClassImplUtil.getInterfaces(this);

java/java-psi-impl/src/com/intellij/psi/impl/source/tree/java/PsiTypeParameterListImpl.java

@@ -39,6 +39,7 @@ public class PsiTypeParameterListImpl extends JavaStubPsiElement<PsiTypeParamete
     super(node);
   }
 
+  @NotNull
   @Override
   public PsiTypeParameter[] getTypeParameters() {
     return getStubOrPsiChildren(JavaStubElementTypes.TYPE_PARAMETER, PsiTypeParameter.ARRAY_FACTORY);

java/java-tests/testSrc/com/intellij/codeInspection/RedundantSuppressTest.java

@@ -43,6 +43,7 @@ public class RedundantSuppressTest extends InspectionTestCase {
       new GlobalInspectionToolWrapper(new UnusedDeclarationInspection())};
 
     myWrapper = new GlobalInspectionToolWrapper(new RedundantSuppressInspection() {
+      @NotNull
       @Override
       protected InspectionToolWrapper[] getInspectionTools(PsiElement psiElement, @NotNull InspectionManager manager) {
         return myInspectionToolWrappers;

json/src/com/intellij/json/JsonBraceMatcher.java

@@ -16,6 +16,7 @@ public class JsonBraceMatcher implements PairedBraceMatcher {
     new BracePair(JsonElementTypes.L_CURLY, JsonElementTypes.R_CURLY, true)
   };
 
+  @NotNull
   @Override
   public BracePair[] getPairs() {
     return PAIRS;

lib/annotations/trove4j/gnu/trove/annotations.xml

@@ -53,6 +53,9 @@
   <item name='gnu.trove.TIntHashingStrategy'>
     <annotation name='java.lang.FunctionalInterface'/>
   </item>
+  <item name='gnu.trove.TIntObjectHashMap int[] keys()'>
+    <annotation name='org.jetbrains.annotations.NotNull'/>
+  </item>
   <item name='gnu.trove.TIntProcedure'>
     <annotation name='java.lang.FunctionalInterface'/>
   </item>

platform/analysis-api/src/com/intellij/codeInspection/InspectionToolProvider.java

@@ -16,6 +16,7 @@
 package com.intellij.codeInspection;
 
 import com.intellij.openapi.extensions.ExtensionPointName;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Plugin's ApplicationComponent or extension that implements this interface will be automatically queried for inspection tool classes.
@@ -27,5 +28,6 @@ public interface InspectionToolProvider {
    * Query method for inspection tools provided by a plugin.
    * @return classes that extend {@link InspectionProfileEntry}
    */
+  @NotNull
   Class[] getInspectionClasses();
 }

platform/analysis-api/src/com/intellij/codeInspection/ex/InspectionElementsMerger.java

@@ -18,6 +18,7 @@ package com.intellij.codeInspection.ex;
 import com.intellij.openapi.extensions.ExtensionPointName;
 import com.intellij.openapi.extensions.Extensions;
 import com.intellij.util.ArrayUtilRt;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.HashMap;
@@ -49,6 +50,7 @@ public abstract class InspectionElementsMerger {
   /**
    * @return the shortNames of the merged inspections
    */
+  @NotNull
   public abstract String[] getSourceToolNames();
 
   /**
@@ -56,6 +58,7 @@ public abstract class InspectionElementsMerger {
    * If this returns an empty string array, the result of getSourceToolNames() is used instead.
    * @return the suppressIds of the merged inspections.
    */
+  @NotNull
   public String[] getSuppressIds() {
     return ArrayUtilRt.EMPTY_STRING_ARRAY;
   }

platform/analysis-api/src/com/intellij/psi/search/scope/packageSet/NamedScopesHolder.java

@@ -81,6 +81,7 @@ public abstract class NamedScopesHolder implements PersistentStateComponent<Elem
     return scopes.toArray(new NamedScope[scopes.size()]);
   }
 
+  @NotNull
   public NamedScope[] getEditableScopes(){
     return myScopes.toArray(new NamedScope[myScopes.size()]);
   }

platform/analysis-impl/src/com/intellij/codeInspection/ex/ExternalAnnotatorBatchInspection.java

@@ -42,6 +42,7 @@ public interface ExternalAnnotatorBatchInspection extends PairedUnfairLocalInspe
   /**
    * To be invoked during batch run
    */
+  @NotNull
   default ProblemDescriptor[] checkFile(@NotNull PsiFile file,
                                         @NotNull GlobalInspectionContext context,
                                         @NotNull InspectionManager manager) {

platform/analysis-impl/src/com/intellij/codeInspection/ex/InspectionElementsMergerBase.java

@@ -19,6 +19,7 @@ import com.intellij.lang.annotation.HighlightSeverity;
 import com.intellij.openapi.util.JDOMUtil;
 import com.intellij.openapi.util.WriteExternalException;
 import org.jdom.Element;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.*;
 
@@ -164,6 +165,7 @@ public abstract class InspectionElementsMergerBase extends InspectionElementsMer
       return myMerger.getMergedToolName();
     }
 
+    @NotNull
     @Override
     public String[] getSourceToolNames() {
       return myMerger.getSourceToolNames();

platform/analysis-impl/src/com/intellij/codeInspection/ex/InspectionProfileImpl.java

@@ -594,6 +594,7 @@ public class InspectionProfileImpl extends NewInspectionProfile {
         return merger.getMergedToolName();
       }
 
+      @NotNull
       @Override
       public String[] getSourceToolNames() {
         return merger.getSourceToolNames();

platform/analysis-impl/src/com/intellij/psi/impl/source/resolve/reference/impl/providers/FileReference.java

@@ -527,6 +527,7 @@ public class FileReference implements PsiFileReference, FileReferenceOwner, PsiP
     }
   }
 
+  @NotNull
   protected static FileReferenceHelper[] getHelpers() {
     return FileReferenceHelperRegistrar.getHelpers();
   }

platform/analysis-impl/src/com/intellij/psi/impl/source/resolve/reference/impl/providers/FileReferenceCompletion.java

@@ -16,6 +16,7 @@
 package com.intellij.psi.impl.source.resolve.reference.impl.providers;
 
 import com.intellij.openapi.components.ServiceManager;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * @author yole
@@ -25,5 +26,6 @@ public abstract class FileReferenceCompletion {
     return ServiceManager.getService(FileReferenceCompletion.class);
   }
 
+  @NotNull
   public abstract Object[] getFileReferenceCompletionVariants(FileReference reference);
 }

platform/analysis-impl/src/com/intellij/psi/impl/source/resolve/reference/impl/providers/FileReferenceHelperRegistrar.java

@@ -17,7 +17,6 @@ package com.intellij.psi.impl.source.resolve.reference.impl.providers;
 
 import com.intellij.openapi.extensions.Extensions;
 import com.intellij.openapi.project.Project;
-import com.intellij.openapi.util.Condition;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.psi.PsiFileSystemItem;
 import com.intellij.util.containers.ContainerUtil;
@@ -33,6 +32,7 @@ public class FileReferenceHelperRegistrar {
   private FileReferenceHelperRegistrar() {
   }
 
+  @NotNull
   public static FileReferenceHelper[] getHelpers() {
     return Extensions.getExtensions(FileReferenceHelper.EP_NAME);
   }

platform/core-api/src/com/intellij/codeInsight/PsiEquivalenceUtil.java

@@ -116,6 +116,7 @@ public class PsiEquivalenceUtil {
     return areElementsEquivalent(element1, element2, null, false);
   }
 
+  @NotNull
   public static PsiElement[] getFilteredChildren(@NotNull final PsiElement element,
                                                  @Nullable Condition<PsiElement> isElementSignificantCondition,
                                                  boolean areCommentsSignificant) {

platform/core-api/src/com/intellij/codeInsight/controlflow/ControlFlow.java

@@ -15,9 +15,12 @@
  */
 package com.intellij.codeInsight.controlflow;
 
+import org.jetbrains.annotations.NotNull;
+
 /**
  * @author oleg
  */
 public interface ControlFlow {
+  @NotNull
   Instruction[] getInstructions();
 }

platform/core-api/src/com/intellij/lang/CompositeLanguage.java

@@ -47,6 +47,7 @@ public class CompositeLanguage extends Language {
     return myFilters.remove(filter);
   }
 
+  @NotNull
   public Language[] getLanguageExtensionsForFile(final PsiFile psi) {
     final List<Language> extensions = new ArrayList<>(1);
     for (LanguageFilter filter : myFilters) {

platform/core-api/src/com/intellij/lang/MetaLanguage.java

@@ -32,6 +32,7 @@ public abstract class MetaLanguage extends Language {
     super(ID);
   }
 
+  @NotNull
   public static MetaLanguage[] all() {
     return Extensions.getExtensions(EP_NAME);
   }

platform/core-api/src/com/intellij/openapi/fileTypes/FileTypeRegistry.java

@@ -40,6 +40,7 @@ public abstract class FileTypeRegistry {
    *
    * @return The list of file types.
    */
+  @NotNull
   public abstract FileType[] getRegisteredFileTypes();
 
   /**