code: public static boolean hasAnnotation(CtField field, String annotationName) {
          FieldInfo info = field.getFieldInfo();
          AnnotationsAttribute ainfo = (AnnotationsAttribute)
              info.getAttribute(AnnotationsAttribute.invisibleTag);
          AnnotationsAttribute ainfo2 = (AnnotationsAttribute)
              info.getAttribute(AnnotationsAttribute.visibleTag);
          return checkAnnotation(ainfo, ainfo2, annotationName);
      }
docs: Returns true if the given field has an annotation set with the given name, returns false otherwise.