docs: private void ensureJdbcType(FieldDescriptorDef fieldDef, String checkLevel) throws ConstraintException
      {
          if (!fieldDef.hasProperty(PropertyHelper.OJB_PROPERTY_JDBC_TYPE))
          {
              if (!fieldDef.hasProperty(PropertyHelper.OJB_PROPERTY_DEFAULT_JDBC_TYPE))
              {
                  throw new ConstraintException("No jdbc-type specified for the field "+fieldDef.getName()+" in class "+fieldDef.getOwner().getName());
              }
  
              fieldDef.setProperty(PropertyHelper.OJB_PROPERTY_JDBC_TYPE, fieldDef.getProperty(PropertyHelper.OJB_PROPERTY_DEFAULT_JDBC_TYPE));
              if (!fieldDef.hasProperty(PropertyHelper.OJB_PROPERTY_CONVERSION) && fieldDef.hasProperty(PropertyHelper.OJB_PROPERTY_DEFAULT_CONVERSION))
              {
                  fieldDef.setProperty(PropertyHelper.OJB_PROPERTY_CONVERSION, fieldDef.getProperty(PropertyHelper.OJB_PROPERTY_DEFAULT_CONVERSION));
              }
          }
          else
          {
              // we could let XDoclet check the type for field declarations but not for modifications (as we could
              // not specify the empty string anymore)
              String jdbcType = fieldDef.getProperty(PropertyHelper.OJB_PROPERTY_JDBC_TYPE);
  
              if (!_jdbcTypes.containsKey(jdbcType))
              {
                  throw new ConstraintException("The field "+fieldDef.getName()+" in class "+fieldDef.getOwner().getName()+" specifies the invalid jdbc type "+jdbcType);
              }
          }
      }