code: public static String getRepeatedFieldType(Field field) {
          FieldType type = field.getType();
          if (type instanceof ScalarFieldType) {
              ScalarFieldType scalarFieldType = (ScalarFieldType) type;
              return LIST + "<" + ScalarFieldTypeUtil.getWrapperType(scalarFieldType) + ">";
          }
          if (type instanceof UserType) {
              UserType userType = (UserType) type;
              return LIST + "<" + UserTypeUtil.getCanonicalName(userType) + ">";
          }
          throw new IllegalArgumentException(field.toString());
      }
docs: Returns a java field type for proto repeated field.