public static boolean isApplicable(@NotNull PsiModifierListOwner modifierListOwner, @NotNull String annotationFQN) {
    VirtualFile file = modifierListOwner.getContainingFile().getVirtualFile();
    return ProjectFileIndex.getInstance(modifierListOwner.getProject()).isInSourceContent(file)
           && AddAnnotationPsiFix.isAvailable(modifierListOwner, annotationFQN);
  }
public static boolean isApplicable(@NotNull PsiModifierListOwner modifierListOwner, @NotNull String annotationFQN)