diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ControlFlowAnalyzer.java b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ControlFlowAnalyzer.java
index bd225a84bb91..b86abc4faa02 100644
--- a/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ControlFlowAnalyzer.java
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/dataFlow/ControlFlowAnalyzer.java
@@ -1510,11 +1510,11 @@ public class ControlFlowAnalyzer extends JavaElementVisitor {
   }
 
   @Nullable
-  public static PsiAnnotation findContractAnnotation(PsiMethod method) {
+  public static PsiAnnotation findContractAnnotation(@NotNull PsiMethod method) {
     return AnnotationUtil.findAnnotationInHierarchy(method, Collections.singleton(ORG_JETBRAINS_ANNOTATIONS_CONTRACT));
   }
 
-  public static boolean isPure(PsiMethod method) {
+  public static boolean isPure(@NotNull PsiMethod method) {
     PsiAnnotation anno = findContractAnnotation(method);
     return anno != null && Boolean.TRUE.equals(AnnotationUtil.getBooleanAttributeValue(anno, "pure"));
   }
diff --git a/java/java-psi-api/src/com/intellij/codeInsight/AnnotationUtil.java b/java/java-psi-api/src/com/intellij/codeInsight/AnnotationUtil.java
index f4455aaa6d02..32553945cfc0 100644
--- a/java/java-psi-api/src/com/intellij/codeInsight/AnnotationUtil.java
+++ b/java/java-psi-api/src/com/intellij/codeInsight/AnnotationUtil.java
@@ -192,7 +192,7 @@ public class AnnotationUtil {
   }
 
   @Nullable
-  public static PsiAnnotation findAnnotationInHierarchy(final PsiModifierListOwner listOwner, @NotNull Set<String> annotationNames) {
+  public static PsiAnnotation findAnnotationInHierarchy(@NotNull final PsiModifierListOwner listOwner, @NotNull Set<String> annotationNames) {
     PsiAnnotation directAnnotation = findAnnotation(listOwner, annotationNames);
     if (directAnnotation != null) return directAnnotation;