Hm, does this actually compile? It seems like it would reference the field AuxId.ALL which isn't actually defined...
Instead of aux_id and aux_id_default_main, maybe just have one:
```python
aux_id = JType("AuxId") \
        .op(read='AuxId.readByte(bb)',
            write='$name.writeByte(bb)',
            default='AuxId.MAIN')
```
(we don't need an AuxId that has a default of "ALL")