void (@NotNull PsiClass aClass) { final PsiReferenceList extendsList = aClass.getExtendsList(); if (extendsList == null) { return; } final PsiJavaCodeReferenceElement[] extendsReferences = extendsList.getReferenceElements(); if (extendsReferences.length > 0) { return; } final PsiReferenceList implementsList = aClass.getImplementsList(); if (implementsList == null) { return; } final PsiJavaCodeReferenceElement[] implementsReferences = implementsList.getReferenceElements(); for (PsiJavaCodeReferenceElement implementsReference : implementsReferences) { checkReference(aClass, implementsReference); } }