[pron]

That's one option. Quasar was configured to run as a runtime agent while the Lombok compiler runs at compile-time, but the Lombok compiler could perhaps indeed be implemented as a Java agent of javac's. This, however, would also require a special configuration of javac, just like all other alternatives. A simpler option is to offer a separate launcher for that compiler (and/or a special build-tool plugin, which is also what Quasar did in its AOT mode).

No matter what, code that wishes to break the guarantees that JDK programs want to make needs to configure that program in some special way so that there's some record, auditable by the application author, saying "this program has been modified in a way that may make it behave not in accordance with its specification".

[sixcorners]

You could do a lot of the lombok things as a runtime agent. I think @ToString, @EqualsAndHashCode, @Synchronized, @Getter(lazy=true), @UtilityClass, @Delegate, and @Cleanup could all be implemented in a runtime agent. Most of the rest could work as a runtime agent too as long as you were willing to type out the method signature (plus maybe a native keyword) for the things you actually want to link against at build time.

I think this would end up being way more difficult to use though and I think it would be perceived to have way more risk compared to lombok as it is now. What do you think?

Also is something wrong with paralleluniverse.co? The root domain seems to go to a gambling site?