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by zebraman 2835 days ago
Personally, I wonder why class-loading is not possible. In the end either a class exists in the closed-world that existed when the project was compiled, or it does not. Of course you cannot change the JDBC connector after it was compiled!

Maybe they could add a whitelist of "known" entry-points for class loading, as to avoid going through a list of 10,000 inner classes that existed at compile time but nobody will ever instance by name.
2 comments
chii 2834 days ago
> Of course you cannot change the JDBC connector after it was compiled!

no, but you can add, dynamically at run time (such as from a user supplied file) a new implementation of the interface. And because as part of the JDBC interface, a connector is able to register itself too (via classloading magic).

JDBC is just an example of a common plugin architecture for extensible software. But perhaps one way to make this work with AOT is to bring along the AOT compiler, and AOT the connector jar when it is being loaded, and treat that binary same as any dynamically linked library!

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jcelerier 2835 days ago
> In the end either a class exists in the closed-world that existed when the project was compiled, or it does not

uh ? no, new classes are added at runtime all the time - at least in C++, dynamic loading of plug-ins is extremely common

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zebraman 2835 days ago
What I'm saying is that it breaks when you do a Class.forName(...), while if such class is known to exist at compile time, it is the same as a switch statement on the class name that returns a new object of the same type; and that second form would be a valid operation.
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jcelerier 2835 days ago
> What I'm saying is that it breaks when you do a Class.forName(...),

but you don't do this. you register the classes according to what is on your file system and you load one that matches your criterions or you ask your user to choose one in a UI of some kind.

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repolfx 2834 days ago
SubstrateVM does support that pattern.

What people are talking about is different. It's when the app genuinely loads plugins that weren't available at compile time, or generates bytecode on the fly.

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