ref = ((JoinColumnConfig) joinColumnCfg[i]).getReferencedColumnName();
if (((ref == null) || ref.equals("")) && size > 1)
throw error(field, L.l("referencedColumnName is required when more than one @JoinColumn is specified."));
IdField key = getKey(id.getKeys(), ref);
if (key == null)
throw error(field, L.l("referencedColumnName '{0}' does not match any key column in '{1}'.",
ref, targetType.getName()));
}