Lombok is an interesting example, but yes, just with reflection you can already get order-dependent behaviors as the docs note. I've been thinking about giving users more control over this commutativity, but it's not clear to me what it should look like. A strict mode where commutativity is disabled entirely? The ability to disable certain commutative parents?

Code that uses Lombok features which change classes (rather than subclassing them) might have a high degree of similarity to Java, but it's not Java.